Last updated: December 1, 2019

Project Ultimate 83 GTI
Videos # 100 to 149 (Sept 2015 - May 2017)

 

The timeline story of the whole project in videos from beginning to end

 

Part 100 (The effort to repair, re-texture and re-color all of the various plastic parts (midnight blue and black) continued with vengeance over the past 10 days, with the biggest successes being the completion of the major dash components. I also got deep into the effort to restore the fender flares which need a lot of work. Finally I also received the Danfoss 400W 12V A/C compressor (which translates into 1500BTUs which is only a small fraction of what a crank driven A/C compressor is capable of putting out but should be sufficient for my needs) and I also started to order a few of the other components that will be necessary to complete the whole A/C system) - September 20, 2015

 

Part 101 (After gluing in the missing chunks plastic, then using SEM plastic filler to fill the extra holes and deep nicks and scratches, and then SEM plastic fine finishing putty, I sprayed the original GTI fender flares/liners with SEM high build flexible primer and sanded them, repeating this process until the surfaces of all of the fenders were smooth and defect free. Then I applied SEM flexible texture coating and then used 400 grit sandpaper to flatten the texture until the VW OEM texture appearance was achieved. I then shot the fenders in Parasol semi-gloss black plastic paint 3 times - they finally look mint again!

I had 2 sets of the rear hatch side shelves - neither set was perfect, each with their cracks and other damage from 3 decades of hard use, so I chose the 2 best examples and started the process of removing the old carpet, gluing in extra supporting plastic material underneath to re-enforce the units, and then used a heat gun to soften the plastic and bend each unit carefully back into correct shape (they warp over the years). Then the process of prepping, filling, sanding and painting using a combination of the SEM plastic repair products, and finally the careful process of measuring & creating a template for the carpet, and then cutting out the carpet, painting it midnight blue, and then gluing it together (after again masking off the non-glue areas). It all worked out nicely in the end but took a lot more time and effort than I had anticipated) - September 30, 2015

 

Part 102 (I have made more progress designing and building the 12V air conditioning system using 2 Perma-cool 1.5x7x14" oil coolers, 2 12V waterproof fans, and a bunch of custom fittings.

A problem I had when testing the engine was that I had mounted a small K&N crankcase breather filter on the end of the plastic OEM breather vent on the front of the ABA block which was not adequate to keep oil from splashing into the filter and then dripping all over the engine and garage floor. The not-so-simple solution was to design a 1.25" stainless steel vent tube that winds its way around all of the obstacles at the front of the engine to the side where the K&N filter can sit vertically above the engine block - with a slope in the vent tube that allows the oil that gets into the tube to drain back into the block.

I also put a lot of time into sorting out the mounting of the 6.5" Hertz woofers into the door frames and figuring out how to modify the window regulators to avoid an interference, plus got well underway with the hole punching process to create 'grills' in the door cards - plus I solved a problem with old warped particle board support by wetting/steaming/pressing/drying the door cards, etc. ...) - October 9, 2015

 

Part 103 (I have both of my door cards drying for a week after wetting the particle board and pressing them flat again so I have taken the time to fire up the motor and start the process of fine tuning the software parameters. It turns out that the canned demo parameters for typical American V8 engines are far too rich for a highly sprung 2.1L 4 cylinder like my highly modified VW ABA engine which seems to need very little fuel at startup or idle ....) - October 15, 2015

 

Part 104 (Over the past week I spent time researching what others have done to program around the needs of individual throttle bodies (ITBs), comparing their work to my own, and there are a number of different approaches that people use: some folks bail on the idea of trying to use the manifold absolute pressure (MAP) sensor as a primary input control to the fuel table and just rely on the throttle position sensor (TPS) called Alpha-N, some elect to use a hybrid approach of MAP and TPS, cutting over at a specific RPM or TPS set-point, but after a lot of study and review of my data logs from prior engine test sessions I decided that with a few changes to my setup I could stick with a pure MAP/speed density fueling strategy. Here's how I have approached things (keeping in mind that I have matched my ITBs with race cams which also add complexity to the tuning challenges as they kill low end vacuum ...).

The closed-loop control (CLC) system in the Holley ECU is very fast and accurate so when the fuel tables or sensors aren't perfect in a particular situation the CLC will almost always fix the problem ...

I realized that one of the things I was fighting was my idle air control (IAC) valve control circuit - when the IAC was open more than 5% to help increase idle RPM, it reduced the MAP sensor's ability to sense the MAP at the throttle bodies - I have a common vacuum plenum that the IAC attaches to at one end and 4 separate -4AN vacuum sense lines running to each ITB - when the IAC opens up it pulls the plenum MAP close to atmospheric, essentially overwhelming the tiny vacuum signals from the ITBs. So I re-calibrated my idle by manually opening up the ITB blades, forcing the IAC to run at 1-3% opening to control the idle when warm, not the prior 12-15% setting. This dropped my warm idle MAP signal from 70-72kPA to 63-65kPA which improves my ability to control fuel flow in and around idle/part throttle. I now have close to 40kPA of MAP range to program with ...

I was also able to move my closed-loop control (CLC) sensitivity factor to the max '5' setting in the ECU, allowing it to nearly instantly correct for any errors in the air-fuel ratio (AFR) being sensed by the wide-band O2 sensor in the exhaust system - this max sensitively setting does not appear to create any instability which is a risk in setting it too high - but I will keep an eye on things in the data logging tables once I get the GTI on the road to see if there are any conditions where I may need to back off on the closed-loop sensitivity. One worry is that I have long, large diameter race headers with the O2 sensor mounted in the collector so there is a time delay from the injection of fuel to the sensing of the AFR ...

I managed to find several happy settings this week: the right IAC 'return to idle' settings - allowing the engine to gently and consistently return to idle smoothly and quickly without over or under-shooting; the right acceleration enrichment (AE vs TPS rate of change) table entries to keep my AFR stable when blipping the throttle - resulting in incredibly quick and satisfying throttle response; and finally my cranking/startup fueling strategy - again, I have continued to lean out all of my fuel tables and now when the engine is warm I only need a tiny fuel prime 'squirt' before cranking and 2.5lbs/hr of cranking fuel, which is pretty much the same as my warm idle fuel setting (which shows how efficient these engines are). And I also found good IAC 'parked' settings to give the cranking engine just enough air when the engine is cold or warm to kick it over cleanly and start without over-revving too high or stumbling before climbing up to the idle rpm set-point.

My fuel tables are now dialed in as close as I need to hit the road and do the rest of the tuning in real-world conditions: my MAP vs RPM fuel tables look quite non-linear as my ITBs and race cams require - the fuel needs are almost flat at low rpm and all MAP settings up to 90kPA, then a steep ramp up of fuel flow up to 101kPA/full throttle - at higher RPM when the ITBs and race cams come into their own, everything transitions to a more linear relationship with MAP signals from 60-101kPA building fuel flow at a more linear rate. Since I can't fully load down the engine on engine stands in my garage, completing these tables will have to wait for the street ...

I found that the Holley ECU doesn't like to try and learn/correct the AFR when the fuel tables are too far off the mark - when-ever I tested the fuel table at a new rpm/MAP range I often had to manually correct (usually lean out) that area of the table before the ECU would jump in and start to correct/learn - this occurred even though I had CLC and learn parameters set to +/-100% offset ranges: if the engine revs to a range where the AFR is way-off the engine will not want to stay there and will hesitate/hunt around for an RPM/MAP point that it likes.
) - October 25, 2015

 

Part 105 (The speaker grills for the door cards were completed successfully, the audio system components are all now together and ready to be installed, the remote mounted Lithium battery was installed and tested with updated battery cables, the final A/C system components arrived and are now ready to be put together and tested out, and most importantly, I got a new Lexan curved cold air intake box made up and tested that looks great under the hood ...) - November 5, 2015

 

Part 106 (Background: as a young electrical engineer 30 years ago I designed power supplies and battery charging systems for mobile devices ...

I was very excited to be able to use the latest greatest automotive grade Lithium ion ferrous phosphate battery technology from Lithium Pros as they are vasty superior to lead acid batteries in several ways: very flat discharge curve (the battery voltage stays high); high high cranking amps without voltage drop (cranking at 12.8V, not 10-11v); very fast charging (all of the available energy from the alternator is immediately stored); many times greater cycle life; deep discharge capability (you can use all of the capacity without damage); and light weight.

But the negatives are: poor performance in sub-zero temperatures; and a less than ideal match to standard automotive alternators that put out 14.4V when Lithium batteries don't want to be charged at more than 3.4V/cell = 13.6V. On-board battery management systems try to shunt the additional voltage and excess current thru internal discharge resistors and it sort-of works but the ideal situation would be an intelligent computer controlled alternator regulator that can rapidly charge the Lithium battery and then back off ... enter my latest project idea ...

I built a circuit that allows full alternator voltage up to 13.6V and then limits it to 13.8V - it does this under ECU control by monitoring the battery voltage and then spoofing the alternator into thinking that it has reached 14.5V by outputting higher than actual voltage back to the alternator 'sense' wire. It uses a charge pump circuit to get 16v to the op amps, and the PWM output of the ECU to send signals to the circuit to increase or decrease the Vsense line. It works perfectly and now I have a charging system that won't limit the life expectancy of the $1200 battery I have.

And I completed the associated battery charge/discharge ECU monitoring circuit which consists of a 75mV/200A shunt in series with the battery and a bi-directional differential voltage amplifier/monitor that puts out a 0-5V signal to the ECU (2.5V = 0 amps, 0V = 66 amps charging, 5V = 66 amps load) ...

I also received my midnight blue headliner material from SMS - it is a perfect match to the VW OEM fabric and is nicely foam backed ...) - November 17, 2015

 

Part 107 (I completed the fabrication and installation of the A/C vents in the center of the dash, fabricated the mounts and modified the dash plastic to allow for the Holley digital dash unit, did the re-wiring to install the Lithium battery current monitor and alternator voltage regulation in ECU command, dismantled the car rotisserie, purchased and setup the EZcarlift, took the car out for its first drive down the lane and in the process damaged both the Wilwood brake callipers and VW Snowflake wheels, repaired all of the damage, did a 4 corner weighing of the car (1540lbs, 70/30 weight distribution) and calculated the approx final weight and distribution: 1800lbs and 66/34 distribution). A lot of progress - my back and hands are worn out and need a rest!) - November 28, 2015

 

Part 108 (I cut the coils to set the correct ride height for the front and rear suspension, plasti-dipped the fresh-cut ends, put in a nylon washer in the top of the front strut bearings under the top nut and washer to take up some slight slack (to avoid the potential for rattling when the suspension is unloaded), confirmed proper ride height after lowering the car onto its wheels, did a basic front wheel alignment, determined that the problem with the steering 'clunk' when changing direction was related to the pinion gear moving up about 0.050" against the pinion gear cover, took apart the steering column, removed the U joints, pulled off the pinion cover, realized that there was really nothing under the cover to positively hold the pinion in place and keep it from moving up and down, machined the pinion cover to accept a friction fit brass shim/bearing surface, machined a matching brass shim of the correct thickness to eliminate the ability for the pinion gear to move vertically (without binding), pressed it into the cover, put the R&P back to together (not easy when the engine and brake servo are in the way), put the steering column back together, adjusted everything, verified that the pinion gear wasn't binding against my new shim but was snug, lowered the car onto its wheels and verified that the direction changing 'clunk' had been successfully eliminated when under load. I am very happy now as the steering is super responsive with the Quaife close-ratio R&P, and that the system has zero play in it and is smooth and very precise now) - December 1, 2015

 

Part 109 (I had to re-route the rear brake lines to solve an interference fit with the 14" VW Snowflake wheels, plus solve a repeat brake fluid leak from one of the master cylinder to rear proportioning vale lines by making and installing a new metric bubble flare to SAE inverted flare line. After flushing the system again the brakes are solid and there are no more fluid leaks!

I decided to mount the GM brake vacuum servo pump on its rubber vibration isolator mounts to a custom stainless steel bracket that I made up and attached to the rain tray holes that originally held the ignition coil. I ran some tests using an adjustable vacuum switch to prove that the brake pressure could be electronically controlled. I then ordered another GM/Holley MAP sensor so that my engine ECU can be used as a master controller of the brake assist vacuum - using a potentiometer that I can turn as I drive I will be able to adjust the brake pedal pressure at will now.

I also received my digital level and Longacre steering toe measurement plates and did a full front/rear alignment (front: 1/8" toe out, -1.3 degrees camber; rear 1/8" tow in, -1.0 degrees camber) and I installed the 3mm spacers for the front wheels and ordered 15mm spacers for the rear axle/brake assemblies, plus matching 40mm 12.9 grade M10x1.5 Allen bolts. I also ordered new longer wheel lugs (M12x1.5x25 and M12x1.5x30 R13 ball seat) for the VW snowflake wheels and an additional set of matching 60 degree conical seat lugs for my lightweight Enkie Racing RP01 wheels and Hoosier racing slicks) - December 11, 2015

 

Part 110 (I was hunting down the few remaining fluid leaks and so it was time to investigate why my Mocal Laminova oil to coolant intercooler was leaking oil. I contacted the SEM Laminova engineering firm in Sweden that makes the unit under contract for Mocal and they said 'Where did you get those brackets? They aren't from us and they are mounted incorrectly. The brackets must be positioned outside of the flanges, not on the inside.' Well, Mocal supplied the brackets but they did not fit on the outside as the ID was too small so I assumed that they needed to be sandwiched in-between the flanges and the body. Wrong assumption. So I machined them to fit, and put everything back together, put coolant and oil back into the system, and, fingers crossed, that will solve that leak. So far, so good.

I built a stainless brace/bracket that triangulates the steering column lower mounting point to the brake assembly/vehicle frame and it has removed about 80% of the flex inherent in the OEM design. I also machined a collar for the top of the steering column that keeps it in place and eliminates any up/down movement. I think I am finished 'tuning' the steering system now - I hope that it will be nice and crisp/precise when driving on the road ....

I received my Lella Autosport 15mm rear axle spacers which are very nice indeed. When using them in conjunction with my 3mm wheel spacers it now looks like my front and rear wheel/tire offsets are identical - I still need to drop the vehicle onto the pavement to verify but I am waiting for the proper bolts as the ones which Lella supplied are about 5mm too long (and the nice 40mm long socket head 12.9 grade bolts I sourced were fine thread and unlike the rear rotor mounting bolts which are (m10x1.25mm) fine thread, the axles mount with std pitch (m10x1.5mm thread) bolts. Me bad. New ones on order now ...) - December 25, 2015

 

Part 111 (For the last few weeks I have been working on the rear wiring and lights, starting by building a new rear wiring harness with all new connectors and LED lights (see prior posts for p/ns), plus I worked on coloring the Hella replacement tail light assemblies to be a hybrid of a US and Euro Spec look to them (I am also building aluminum/carbon fiber bumpers that will be a hybrid of US and Euro Spec look to them - shaped like the US bumpers but scaled a bit smaller and closer to the body). I got the powered radio antenna installed in the back, plus sorted out the backup camera mounting and wiring, although I blew up the camera by connecting it to 12V when it needed 3.3V. I also got the 12.9 grade rear axle mounting bolts installed with the Lella AutoSport 15mm spacers) - January 17, 2015

 

Part 112 (I finally got to the point where I had all of the parts necessary to assemble and bench test the electrical A/C system. I used low temperature aluminum/copper solder (500 degree F) and I didn't really do a very good job on the receiver/drier connectors as I didn't apply the massive amounts of flux that that particular solder requires - so I had to re-solder a few places and still need to chase down a few remaining leaks (I have ordered Harris Al-Cor brazing wire and will re-do all of the connectors and I may also switch over to flex lines ...). All of the copper compression fittings are leak-free but another set of leaks occurred after 24 hours at the NPT teflon tape fittings as the POE oil in the system actually dissolves teflon tape - so I replaced the white tape with yellow gas spec tape and it seems to hold better (we'll see ...). The system was charged up with R134a refrigerant and it came to life. It will need tuning to bring out its maximum potential: the oil coolers I am currently using as the evaporator and condenser cores aren't very thermally efficient when used in an A/C system and so I will look more into finding small A/C cores that will fit my application, plus I need to determine the ideal R134a charge load - I added too much at one point in my testing and the performance dropped almost to zero (I think the low side pressure should be around 25psi and it was up to 40psi). With a medium-high fan setting I saw about an 8 degree F drop in air temperature coming thru the evaporator and I'd like to see more like 10-15 degrees drop (this compares to commercial systems that are >4x more powerful and can drop the air temperatures from 80+ degrees F to below 50 degrees F).

I thought I should provide some basic automotive A/C background info and relate that to this project: A typical crank/belt driven automotive A/C compressor is capable of 10-20000 BTU/hr output capability. Due to the law of thermodynamics heat/energy removal (a thermal transfer process) isn't a watt for watt 1:1 relationship. e.g 1 watt of energy input into the compressor translates into approx 2 watts of energy removal from the air. For my tiny little Danfoss BD250GH compressor, which draws around 10-15 amps at 12.5V, or up to 200W, it provides up to 400W of energy removal, or around 1300 BTU/hr. I could upgrade my compressor to 2 other available units (http://www.seanhylandmotorsport.com/blog/12-v-air-conditioning-compressor-how-can-you-decide-if-one-is-right-for-you/) that consume 20-31+ amps of power for between 3000-6000 BTU/hr of cooling capacity in a package that is roughly the same weight and size (7-10lbs) as my Danfoss compressor (with easier to manage automotive A/C fittings pre-installed - but the compressors have less complex electronics that can't speed up and down the compressor as energy demands change - you are limited to turning them on/off). Air weighs 0.04Kg/cu-ft and the fan I am testing with is around 150cfm, which means that the mk1 golf with its approx 80cu-ft of interior volume would have its air exchanged every 30 seconds and in that case my little compressor is removing around 3-4 degrees C of temperature from that volume of air. Dry air has a specific heat factor of 1000J/kg-C (in other words, it takes 1000J to raise the temperature of 1 Kg of air 1 degree C and 1W = 1J/s). My fan is moving 150cfm or 2.5cf/s, or .1Kg/s or 100W per 1 degree C of cooling = 300-400W of cooling, so my system is pretty much running as expected. If I slow the fan speed down 70% to an equivalent to a 'low' blower setting I can then expect the air temperature drop to be around 10 degrees C. And that is with a small Danfoss compressor. You have to remember that the sun radiates a huge amount of energy into the car interior while driving and when a car's interior is hot it requires a huge input of cooling to bring the temperature back down, and that is why 3000+ BTU/hr is a better starting point for a 12V electrically powered A/C system. I think I can make my little 1300 BTU/hr system work effectively but I might end up changing to the larger compressor in the end. This is a big science fair project and so I am learning and experimenting along the way. Fun stuff!

I received my p/n 191501639A rear axle bearing dust shields and they fit) - January 24, 2015

 

Part 113 (My 33 year old plastic front grill was beaten up and needed to be sanded down with 600/1000/2000/3000 grit wet sandpaper, and then masked off and painted with the red GTI edge stripes, plus the GTI badges needed to be color matched. The grill cleaning and sanding went really well, but my initial attempts at using a hard rubber roller to paint on the Parasol red plastic paint were a near complete failure as the paint dried on the roller very quickly (there is a lot of powerful solvent in the paint that evaporates super fast) plus the solvent in the paint which helps bite into the plastic also tends to dissolve the prior layers of paint when disturbed by a roller or brush - but isn't a problem when spray painting. I ended up destroying 2 rear GTI badges before giving up and finding NOS GTI badges on ebay and then masked off and spray painted the red stripe on the grill. That worked out, but the masking was very tricky/time consuming, plus some of the paint found its way under and around the masking so it took another 4-5 hours of wet sanding and touching up the stripe with a fine model spray gun ... in the end it was all worth it as the grill looks awesome now. Plus I successfully hand painted the front GTI badge with the same red paint and then carefully block sanded it down smooth to match the grill stripe (it was a bit off and now everything matches 100%). I am really happy with the look now.

I then took all of my new parts for the electrical A/C system and put them on the prototype system: new #6 A/C barrier hose and fittings for the drier/filter unit, lots of temperature sensors to bench test the system, and more air boxes to fine tune the performance and help squeeze every last drop of performance and efficiency from this system (given that it is a bit marginal re. cooling capacity). In the end the amount of R134a refrigerant charge that provided the best performance was 35psi on the low side with the compressor running at max speed (4,400rpm at 13.5amps/13.3V). This provided close to 7 degrees C of air cooling across the evaporator at an equivalent to a 'low' blower setting in the car and a little over 4 degrees C of air cooling at an equivalent of a 'medium/high' blower setting (150cfm - enough to change the air in the cabin every 30 seconds). The performance #s are solid: 160W of electrical energy providing approx 400W of cooling (1,400BTU/hr). Since I have a small racing alternator I cannot afford more than about 15amps of continuous current draw at idle, so if this proves to be too little cooling the next step up in compressors is closer to 2x in both current draw and cooling, and is also 2x more expensive ($1,200 vs $600). I'll install this system and if it is not sufficient for my summer needs and I am not at the edge of my alternator capacity I might upgrade to a larger compressor .... we'll see - February 8, 2016

 

Part 114 (I fabricated an aluminum bracket out of 1/8" material using my new sheet metal brake to mount my Hella air horns (the same ones I had on my old GTI back in the day) - they fit perfectly beside the water pump housing. I then mounted the HID high voltage transformers under the radiator area, and also figured out how best to mount the MAP sensor that I will be using to measure and control the brake servo vacuum. I also finished cleaning up the trunk area where I had ground off the wiring metal tabs (that I won't be needing), filling, sanding, priming, base coating and clear coating it all. finally, I got started on the ash tray which required sanding and filling, then texturing and painting before I can fabricate an aluminum panel for the inside of it to mount 6 rocker switches (Ignition on, engine start, engine kill, A/C on, NO2 enable, NO2 purge) and 5 potentiometers (A/C level, Seat Heater 1/2, Brake Servo Vac, blower speed) - February 17, 2016

 

Part 115 (I ordered and installed some OEM rear license plate mounting h/w and finally mounted my original GTI license plate on the back of the GTI. A milestone!

I managed to cut/punch/nibble/bend an aluminum bracket to mount the 6 switches and 5 pots in the ash tray, plus design and print to a durable label with all of the panel info. It barely fits but it does fit and looks the part (I am happy about how it turned out). I'll have to wire up a 15 circuit Molex connector to it and then from there to the ECU next ...

I found an excellent electric A/C compressor from Boyard in China that is a 2.5x capacity step-up from my Danfoss compressor that I had bench tested. Here are the differences:

Danfoss BD250GH: 2.5cc cylinder volume, 2500-4400rpm, max 12amps@13.5V (162W) to produce approx 350W of cooling (1200BTU/hr - a COP efficiency of 2.1), 11.6lbs with controller, results in a drop in air temperature of around 5 degrees C at mid-range blower fan settings. Variable speed so current consumption can be reduced.

Boyard JVB075Z12 : 7.5cc cylinder volume, 2500-3700rpm, 25amps@13.5V (340W) to produce approx 850W watts of cooling (2900BTU/hr [higher COP efficiency of 2.5] of cooling at 3300rpm (so at 3700rpm it will produce closer to 3250BTU/hr at 30amps), 16lbs with controller, should result in a temperature drop of closer to 15 degrees C in comparison to the Danfoss unit at 3700rpm.

I am waiting for new A/C connectors as I will switch completely over to #6 and #8 reduced barrier A/C hose and fittings given the larger capacity of this unit. As a variable speed compressor the current draw can also be substantially reduced as required - my ECU will control the compressor speed based on cooling system demands) - March 2, 2016

 

Part 116 (I got the ash tray control panel wired up, test mounted, and built a wiring harness to connect it to the ECU, then I completed the wiring and installation of all lights in the rear of the car, and then built and installed a front-to-rear wiring harness that runs inside the frame of the car, then I connected the wiring harness into the electrical panel and ECU at the front of the car, and also sorted out all of the dash and stalk wiring components that I will use (a mix of old and new), plus I got fairly far into building the wheel well audio and battery system Lexan mounting solution. Finally, I machined and installed the #6 and #8 A/C fittings onto the new Boyard A/C compressor and then assembled and bench tested the system: was a big improvement over the prior Danfoss compressor, putting out >800W of cooling power (almost 3000BTU/hr), vs. 350W for the Danfoss unit. This translates into an 8-10 degree C temperature drop across the evaporator at a medium to high blower speed setting which will make it an effective A/C solution for outside temperatures of up to 30 degrees C or more, at a typical 15-25amp current draw) - March 27, 2016

 

Part 117 (The complete audio system was setup and tested (a combination of vintage and state of the art components) - it was a success. The Lithium battery and audio system was then installed in the car while the dash was prepared by fabricating a mounting bracket for the Concord tape deck, plus the ash tray control console stops were fabricated and installed. The A/C system was bench tested for current consumption at different compressor speeds, and another A/C compressor controller was ordered that has a shorter 5s startup delay so I can duty cycle the compressor to achieve even lower cooling capacity. Mounting brackets were fabricated/welded up/painted for the A/C compressor and controller unit and everything was test mounted - again, a success. Finally, the A/C condenser was assembled with water proof fans and was mounted under the car) - April 14, 2016

 

Part 118 (Major wiring is now complete. Yes, after a lot of work the wiring job is coming to a close. Blame it on my desire for complexity and computer control over all aspects of the car, but it is almost entirely done now - some of the final wiring will have to wait for the rest of the interior to go in, etc.) - May 3, 2016

 

Part 119 (The final countdown to project completion begins! ... I think I have around 100 hours left to go and a number of those items include things that can be done after road licensing/certification and shakedown testing (putting decals on, finishing my 2/3rd size carbon fiber/aluminum bumpers, some interior trim, etc.).

Over the past 2 weeks I machined up a smaller steering column collar, and installed it along with a new top column bearing assembly and ignition switch, put weatherpack connectors on the seat heaters, sorted out all of the h/w and plastic bits needed t put the seats together (and ordered a few missing parts), got the sunroof sorted out as well by refinishing the parts and ordering several new items (the wind deflector and levers, new cable assemblies), epoxied on quick connect o-ring fittings to all of the A/C components, got the front and rear cameras installed and connected to the rear view mirror, and fabricated a transition air box for the evaporator to blower motor ...) - May 20, 2016

 

Part 120 (The big day finally arrived today with the completion of the installation, vacuum testing, R134a refrigerant charging, and system performance verification. The system gets nicely cold, frosting up the TXV thermal expansion valve and lines running to the Evaporator, plus the Evaporator itself gets frosty on some of its surfaces. The air temperature drops up to 8 degrees C flowing thru the Evaporator, and I expect that the total air temperature drop will be more than 10 degrees C as the rain tray area gets chilly from all of the cold A/C components there and that has an indirect impact on the air flowing thru that area on its way to the Evaporator. We'll see once the GTI is on the road in June ...) - May 25, 2016

 

Part 121 (While I was attempting to put the seats together I found out that the recline mechanism on the driver seat was jammed for some reason and it turned out that the upholstery guy (who shall remain unnamed) ruined the mechanism by drilling holes and installing sheet metal screws into the cross tube and shaft inside it - the shaft was jammed/damaged and needed to be replaced. And it turned out after stripping the seats down to see what was going on that the welds from the tube ends to the side frames were broken as well. It was a big job to design and fabricate a full repair but in the end the seat is stronger and straighter than ever and I am very happy with the final result now.

The sunroof system is now installed, complete with new silicon rubber rear drain tubes, new spring retainers, cable/lifters, headliner, and a new wind deflector) - June 7, 2016

 

Part 122 (Headliner - Wow! This was a much more involved task than I had envisioned. 2 weeks of thrashing and it is finally complete. One of the challenges is getting the foam backed headliner material (from SMS Automotive Fabrics) to be cemented flat, straight, etc. over such a large area, another is all of the sunroof interface issues, and in my particular situation the metal bosses that the sunroof mechanism screws into are lose and require vice-grips to hold from the under side when attaching the mechanism from the top so there is no way to put the sunroof in AFTER the headliner is in, so I had gymnastics getting the headliner flowing correctly into the sunroof opening and then attaching the trim - the video explains it all. In the end it is 100% to my satisfaction - it just took about 20 hours longer than I had budgeted ... The dash is going in starting this weekend ... (I am on a roll now)) - June 24, 2016

 

Part 123 (The dash is 'in' - minus the speaker wiring and final lower console assembly which will have to wait until the doors and carpet is in - everything fits well and works correctly and I get decent airflow thru my 'custom' centre air vents which is great. I have a small amp remote control dial placed below the ash tray that allows me to quickly adjust things like subwoofer volume and it 'just' fits and looks subtle enough. I now have to rebuild my paint booth this weekend and re-base/clear the front fenders (one of them had a small rust bubble and they both needed more clear coats for final wet sanding), and re-clearing the doors (again, I am not happy with the slight waviness from prior wet sanding so want to get them dead flat), plus I damaged the rear lower valence near the muffler by lowering the car onto my heater which needs fixing ... then I can get the doors assembled and mounted and all of the glass into the car, etc.) - June 29, 2016

 

Part 124 (I built a temporary paint booth in my garage to re-paint my doors and front fenders as they needed to be 'improved' somewhat - and I am very happy with the results (almost no dust in the air so the painting was clean). I also did some touch-up bodywork/painting on the chassis where there were a few solvent bubbles (thankfully only on the drip rail) plus I repaired the damage to the lower rear valence and fixed one rust blister on the inner lip of one of the rear fenders. While I had the temporary paint booth setup in the garage for the doors and fenders I took advantage of the setup and used it to apply Parasol Varikote vinyl dye to the door cards after masking off the chrome and red striping. Once the doors are polished I can then assemble them ...) - July 4, 2016

 

Part 125 (The door cards were completed after some bloopers, all the body panels were installed and gapped, fender flairs and spoiler attached, the decal stripes were applied, and the carbon/aluminum custom bumpers were partially completed) - July 17, 2016

 

Part 126 (I got back from a trip a bit early and managed to complete the front bumper semi-completed - I still want to make custom caps - see video for explanation.) - July 21, 2016

 

Part 127 (After holidays and such I have managed to get the project somewhat back on the fast track. This last week I finished the carbon/foam/aluminum bumpers, installed all of the lexan panels, mounted and adjusted the gap on the rear hatch/tailgate, mounted the door handles, re-keyed the lock cylinders, rebuilt, painted and mounted the mirrors, and started on the rest of the door assembly work. T minus 40-50 hours max now before licensing it ...) - August 10, 2016

 

Part 128 (The last 2 weeks were an intense period of battling to put the doors together with the lexan windows and non-OEM windows lifter mechanism, seals, locks, speakers, etc. In the end there was a conflict between the speakers and the lifter mechanism that has caused me to reconsider the design and move towards a mk2 electric lifter mechanism using the hand crank arm as a momentary up/down switch  - the video explains why. I am also going to get a local plastics firm to heat bend some Margard lexan to the correct curved shape as the flat lexan sheets don't take the proper shape and are hard to move in the channels. For now the driver window works but the passenger window is fixed - I have the option of simply putting in the OEM glass and the OEM lifter mechanism but I'll try the above approach. The doors look great overall and the sub-woofer ended up working out really well. The latch for the carbon fiber hood had to be re-worked a bit and is now functioning properly. I am T minus 1 week to project completion now ...) - August 22, 2016

 

Part 129 (33 years to the month, my GTI sat again in my childhood home’s driveway: I took delivery of my original GTI in May of ’83 but it didn’t get licensed until August ’83 (no job, no money, no license …).

I drove about 3 hours in the car in total today - yes it was driven in the rain and got nice and dirty (I took my family and my dad out for rides), shaking out the initial bugs and gremlins. It will be about 1-2 months to get the car behaving the part (fast, fun, safe and semi-civilized). I discovered lots of things that need addressing already: the brakes are a bit mushy and need professional bleeding, the steering alignment also could use a pro setup alignment, there are some squeaks and rattles, the fuel gauge needs calibration, one of the radiator fans is DOA (I don’t think I will need 2 after all so maybe it will just be disabled), for some reason the engine shuts off at 6,000rpm, just as the fun starts, there was a fuel leak when I topped up the tank, the windows don’t roll up properly, it is a bit harsh and noisy, etc - you get the idea ...

The GTI is spending the night at the mechanics and should be certified road worthy tomorrow so it can be fully licensed. I will then have time to run system diagnostics on the crank and cam triggers - I suspect that the old-school analog inductive crank sensor is crapping out and may have to be replaced with an external digital hall effect crank sensor (which requires that a 60-2 tooth wheel be placed between the crank pulley and the crank itself). There may be something else going on but the computer says 'lost sync' in the RPM readout and the ECU goes a bit nuts for a while so ...

The dash final installation went well but the plastic bits rub and squeak against each other when driving on bumpy roads so I will have to start to place some felt tape around various places to get it to quieten down.

The carpet is from stockinteriors.com and is 'mass-backed' meaning that it is a heavier and stiffer carpet than stock and is a pain in the ass to cut and get moulded to the body shape - it took the addition of some stiff foam under the carpet in the front to work out. Now it all looks great. 

The seats went in place nicely. The new foam and leather wrapped wheel worked out too.

With fuel in the tank, carpet mats, A/C, stereo, sun-roof, full interior, etc. it scaled in at 1950lbs, with a 66/33 weight distribution. With some of this crap pulled out on race days I'll have an 1800lbs car.

I have 3/4" gaps from the top of the tires to the fenders all-round so ride height is perfect. Suspension is H&R race springs and Bilstein race struts and shocks. A bit stiff but not as bad as I thought it might be. Still, I will also order in some H&R sport springs and try them out)
- September 1, 2016

 

Part 130 (Even though I took the car to a garage with its own race teams who understand the safety benefits of Lexan windows, they were unable to certify the car for road use simply because all windows must have the DOT stamp on them, no exceptions. Turns out it is a big deal. So ...

I am not against putting glass in as it will only add 20lbs or so to the weight of the car, make it quieter, allow me to use 3M CR90 film to keep it cooler without tinting the windows darker, will be much more durable, etc. but there doesn't seem to be any sources of clear replacement mk1 glass in North America available (let me know if you have a source ... or I will be forced to order in from Europe and risk breakage).

I also need to get an externally mounted digital hall effect crank sensor fabricated so that I can rev the engine above 6,000rpm. And since I have 'down time' in front of me, I can get the mk2 electric window lift mechanism sorted out (hope I can make it work), and can also swap in a larger A/C thermal expansion valve as the current one seems to be undersized.

I asked the mechanics to look into why the Quaife R&P steering was a bit stiff when turning to the right and it looks like something inside the unit is binding - maybe I have the pinion set screw too tight? Anyway, with only 3 hours of driving on this R&P I am already starting to hate it: way too much low speed effort, making parking and low speed driving almost dangerous. The mechanics said 'only use that kind of R&P on the track, not on a street car' and I agree now. I'll likely swap in a stock unit.

I am not super happy with the ride quality using the H&R race springs either - the car bounces around, being such a short wheel base car and I think that for general road use and enjoyment I will need to go to the H&R sport springs and maybe also increase ride height 0.25" or so to give this car more suspension travel as it is minimal at the moment.

Such is the path of debugging a completely new and fully custom car ... stay tuned and thank you everyone for your support along the way) - September 3, 2016

 

Part 131 (I had the GTI in at Weissach (http://www.weissach.com/why-weissach/) who have had an intimate relationship with several of my cars over the years (e.g. they completely re-built my BMW 540i into a Dinan supercharged monster (plus cams, diff, suspension, brakes), they do 911 Ruf conversions, etc.). They pulled my steering Rack & Pinion unit in and out several times and adjusted the pinion pre-load and other tolerances until the steering with the Quaife ratios felt 'just right', flushed and adjusted the brakes so that the car stops NOW, and otherwise double-checked things for me. I put a the 10K resistor in series with the inductive crank sensor, added more shielding and got my full 8,200rpm limit on my motor, plus I changed around some of the electric water pump and radiator fan cooling programming so that the motor temperature was more even, and then set about road testing it. Yes, I still need to put in DOT stamped glass for my final road inspection certificate but that is only a matter of time now.

What was exciting was standing on the throttle and brakes and sawing on the steering wheel and having this car do its thing: and what a performance envelope is emerging now: 115-120% volumetric efficiency above 7,000rpm, an estimated 250hp from 7,500-8,000rpm based on a 0.42 BSFC estimate for this very finely tuned ITB based 16V motor (with full race 288 solid lifter cams, large valves, exhaust, 12:1 CR, no crank accessories to drive, etc.). What is mind blowing is that the motor pulls strongly without burping or farting from 1,500rpm onwards - I can short shift from 1st to 3rd and it will happily pull away without complaining. Oh, I still have to test that 150hp progressive nitrous system ...

I know I initially complained about the Quaife rack & pinion close ratio manual steering box as being 'too tiring' but now that it is adjusted it is beautiful to use and with a bit of planning and finesse low speed operation is fine. And the Bilstein race struts/shocks and H&R race springs, with the hollow rear sway bar (and no front bar) is an excellent combination - no body roll but still compliant. And I think I got the right compromises with the rubber HD strut mounts, the rubber HD side and rear motor mounts, the soft poly front motor mount, the OEM R&P rubber mounts, the poly A-arm bushings, and the Delrin rear trailing arm bushings and custom bearings - rubber is where the harshness can transmit and the poly and Delrin is where it won't and will provide improved precision. Yes, more poly and Delrin would provide an even greater degree of precision but will also create noise and harshness. I think I may have lucked out and found the right balance off the mark ...

I now have at least a month to get the glass in from Europe - maybe I'll find some clear glass in the US but maybe not ...) - September 12, 2016

 

Part 132 (I sourced a new green tinted front windshield that matches the OEM green tint of the original GTI windows (I have all of the windows from the old car except the windshield) ... but the new one is a glue-in which has 1cm larger dimensions and a black-out mask so it cannot be mounted using the rubber surround that I was using for the Lexan windshield. I have sourced the glue, primer and rubber trim moulding and will install it next week. I am going to use cerium oxide powder and felt disks to polish the old glass side windows to remove the usual wear and tear marks and then will finish installing all of this glass so I can get my final inspection completed and the car licensed.

The Davies Craig electric water pump controller uses a thermistor that they recommend be installed in the return line to the engine block. Wrong move. This resulted in wildly fluctuating cylinder head temperatures as my radiator does an excellent job of cooling the hot fluid before the thermistor reads it so I ripped up the nasty coolant return line plumbing and replaced everything with a clean -20AN stainless line from the oil cooler to the block and then machined the coolant flange on the side of the cylinder head to accept the thermistor - now the cylinder head temperature is stable at 190F +/- 2 degrees at all times and my oil temperature is also lower.

I ran full audio system frequency analysis on all drivers and got the system's frequency response to be flat from 20-20,000Hz and also got the time delays programmed for each driver. The system is almost 1300 watts RMS and is both crisp, clean and crazy loud if required (and the sub-woofer can be turned up to shake the car to death). Frankly, when the engine is running the audio system seems somewhat of a lessor interest, but when the engine is off the audio system is a joy to have - bluetooth streaming, hands-free cellular calls, plus the old-school Concord cassette deck with both Dolby B/C and dBx noise reduction (the tape system with high end metal tapes is pretty much CD quality - but 30+ years old).

Yes, the VW mk2 electric window mechanisms can be successfully adapted to the mk1 - I just did it. You will need p/n VW: 191837402C or 191837462A for the right side, and p/n VW: 191837401C or 191837461A for the left side and I recommend sourcing the mk2 lift channels as well ( p/n VW 867898571) but I did not want to wait so modified the mk1 channels to work) - September 12, 2016

 

Part 133 (Well, I ended up in the hospital last week with pneumonia after fighting a losing battle with a chest injection/cough for the past 2 months. I am on 'the good drugs' now and they are really helping me get back on my feet. I did low key things on the GTI during this period: I used Cerium Oxide to polish the old set of glass side windows to bring them back to life, and I got my youngest son, Evan, who is 18, to help me glue-in the new front windshield ...) - October 10, 2016

 

Part 134 (I completed the installation of all of the glass, including the VW mk2 electric window mechanisms and the mk2 lift channels as well, plus I made up some trick custom bi-directional window lift switches that use the old crank arm.

I also swapped out the 1kW A/C TXV for a 2kW unit and the system now pumps more R134a thru the Evaporator at peak compressor speeds, achieving higher cooling efficiency/performance.

I then got the car inspected, certified road worthy, and licensed this week and then went out and drove it around for more than 3 hours - what a joy!

I confirmed a number of basic performance parameters via a series of full throttle acceleration runs and some hard cornering and slaloming dynamic tests: There is practically zero body roll with this suspension system and there is tons of grip but the car is not overly stiff/harsh except on rough concrete expansion joints where the car bounces around with its short wheel base. The estimated 0-60mph time seems around 4s but the tires can't hold the power in 1st gear at any RPM >3,500 so I won't know the true potential until I bolt the slicks on at the track. The computer has provided fuel data which allows me to estimate power and torque #s by using BSFC (for a street engine 0.5lbs/hp-hr of fuel consumption is reasonable but highly tuned race engines such as mine are more efficient at around 0.42lbs/hp-hr). At 0.42 BSFC my engine is putting out 260hp @ 7,250rpm and 200 ft-lbs of torque from 4,500-7,000rpm which is quite something. Obviously this needs to be backed up with dyno pulls, g-meter acceleration data, and track 1/4 mile racing results. I'll have the g-meter acceleration data in a few weeks.

The engine exhaust smells more than I think it should and the oily black soot in the exhaust pipe indicates that the rings have not fully seated yet. I took out the spark plugs and they are absolutely clean looking on the electrical contacts but the metal base rings are a bit oily. I also used a computer/USB microscope to look into the combustion chambers and inspect the pistons, block cylinder walls, and valves - I saw cross-hatching marks still on the cylinder walls which look evenly shiny 360 degrees around, but the edges of the combustion chambers were a little oily looking, with one cylinder actually showing a small drop of oil on the wall, plus the piston crowns looked a little fouled in spots and also a bit wet in spots from oil. The question I now have for engine builders is: how long should it take for my rings to seal (I only have about 4-5 hours of real engine running time where I have been driving the car and less than 10 full throttle acceleration runs to attempt to fully seat these racing rings)? Is there a problem with my rings not seating? I have been using Joe Gibbs Driven Racing Oil 00106 BR 15W-50 Break-In Motor Oil.

After my 3hr drive I realized that my new mini Denso alternator was burned out/DOA. It could have been my ECU control circuit which tricks the alternator into limiting its output voltage to 13.8V (for my LiFePO4 battery) by providing 14.6V into the Vsense input when the output reaches 13.8V. Anyway, I have ordered a PowerMaster 8188 XS Volt 75 Amp mini Denso alternator from Summit Racing with expedited shipping - this unit has fully adjustable output voltage capabilities plus an input that when grounded will reduce the output voltage 1.25V to cut the power draw from the engine by over 50% - saving a few hp during WOT acceleration runs) - October 30, 2016

 

Part 135 (It is now late fall/early winter in the Pacific North West and the leaves have mostly fallen off the trees and the rain is falling almost every day – it is cold, wet, and the roads are dirty. Driving my GTI in these conditions creates a full hour of post-ride detailing clean-up so it is not worth it to drive unless I really need to. I will likely have to wait a few months before getting a proper chance to complete performance tests …

That said, I was going to use my new G-tech RR performance analyzer to initially bench-mark the power and acceleration of my GTI but it won’t even sync to the GPS satellites in this cloudy weather …

That said I managed to complete a series of hill climbs, completing around 10,000’ of vertical and put in almost 200 miles of aggressive driving on the GTI to help break-in the piston rings/cylinder walls – the exhaust now smells cleaner.

My original alternator had burned out so I purchased the new PowerMaster XS Volt mini denso alternator model 8188 (75amps) but it produced too little idle charging current with my 2:1 pulley ratio, even at 1100rpm engine speed, so I ended up switching to the model 8168 and changed to 2.5:1 ratio pulleys and ended up with over 30amp of charging at idle so that problem is solved. The XS Volt alternators have adjustable output voltage to keep my LiFePO4 battery at a max of 13.8V – it also has an input that allows ECU control over the voltage so I get the best of both worlds – fast charging at idle and a 13.8V limit.

I have been chasing down a few minor oil leaks that are coming from the oil pan seal and possibly the aluminum cover above the pan on the passenger side, plus a very minor leak either from the head gasket at the back next to cyl #4 or ??? plus there has been a minor exhaust header leak around the side of cyl #4 – I have tightened the header up and it is sealing better now but isn’t perfect so I am thinking of trying some Permatex exhaust sealant on the header gasket. I have also ordered some Toyota gasket sealant for the oil pan – to put a thin layer on each side before installing the rubber gasket again …

I cut and installed new window seals for the driver and passenger roll-up windows as I had previously cut them too short and the seals had slight gaps – this time I cut a bit too long which is actually perfect as there is now pressure between the seals and yet they still sit flush.

I think I may have damaged my outer CV joints from my engine testing using the brakes before the car was on the road - having them at an angle during testing ... there is some free play in them now which isn't great so I have ordered some competition axles ...

I cleaned up a pair of mk1 midnight blue visors with dry cleaning fluid and re-painted the edge material and now they are ready for installation.

Finally, I have been trying to resolve an issue of brake pedal ‘feel’ where the first 1-2” of travel are quite a bit softer than the rest of the travel when the pedal firms up nicely. I think I have found the problem: I mixed up the servo from a mk1 16V and the master cylinder from a mk3 non-ABS model. So I have now ordered a new mk3 non-ABS servo and will modify/thread the rod to fit my custom brake pedal assembly. Fingers crossed that the pedal feel will be better after the swap. Oh, the 16V servo was leaking vacuum too which was a bit of a pain …) - November 20, 2016

 

Part 136 (The new 8168 Powermaster XsVolt alternator is working perfectly - my LiFePO4 battery appreciates it.

I ordered a VW mk3 non-ABS brake servo/booster because I had been using a leaky mk1 servo unit. I experimented with some shims between it and the master cylinder (which is a 22.2mm unit, also a mk3) and initially took up too much of the slack and had the car self braking! But with a single 12mm stainless washer as a shim it reduced pedal travel and now the brakes are feeling pretty good. I have the ability to electronically set the amount of vacuum assist so I have been trying out various settings.

One problem I still have with these much improved brakes (using Wilwood 4 piston calipers and 10.1" disks up front and mk3 disks on the back with a Wilwood proportioning valve) is that even with the valve on full minimum I still get rear lockup first. I am ordering fixed in-line pressure reduction valves to try out (I will leave the adjustable valve in the circuit) plus I am going to order a 25.4mm master cylinder which will reduce pedal travel another 30% (but also increase effort by the same ratio) - ideally I would like to heal and toe with minimal pedal travel and I can simply crank up the vacuum assist if I want a softer effort ....

My old fuel tank level sender unit was crapping out so I ordered a new VDO plastic replacement unit which worked out well but I had to modify the connector to create a right-angle version and now all is well.

It is full-on winter here now with snow and ice on the roads (and salt!) but I managed to get a full sunny dry afternoon this last weekend to do some performance testing. I had acquired a Gtech RR performance analyzer to measure 0-60, 60-0, power, cornering, etc. so I was excited to see what this GTI could do. Well, the Gtech unit had limited measurement accuracy as it seems to have a broken GPS antenna and couldn't get a fix on more than 6 satellites but it did give me basic 0-60mph info: with no off-the-line traction and short shifting into 2nd gear I saw repeated 6.0s times - this is with street tires, dirty conditions and almost freezing temperatures. With good conditions (the track!) I should be able to launch at a high enough RPM to get on the cams (I need 4,000rpm min) to get a high 4s time. The engine is pulling like crazy, putting out 0.6gs of acceleration at 60mph in 2nd gear (my old mustang with its 300hp engine only managed 0.42gs in 2nd gear at 45mph).

I also swapped out my Spal radiator fans for new units as I think I damaged them by running them at a 30% PWM duty cycle which seemed to have fried the brushes - current pulse arcing) - the fans were rattling and sounding horrible. I have now set the minimum duty cycle to 50% which is what Spal's own controller starts at) - December 6, 2016

 

Part 137 (An important part of any project is the relationship with your vendors who supply all of the components and much of the technical support. In this video I review the key vendors who I relied on:

Ebay and Amazon ...
Josh Arnold (US) - engine builder
Techtonics Turning (US) - major project supporter, providing a ton of components and support
VW Heritage (UK) - specialty VW parts
ESC Tuning (US) - specialty VW parts
Bolt Action (NL) - specialty VW parts
Summit Racing (US) - racing auto parts
SMS Automotive Fabrics (US) - interior fabrics
EAA Engineering (US) - custom fabricated VW parts
ACW Motorsports Plastics (UK) - Lexan windows
BS&S Radiators (Canada) - custom radiators
Bolt Depot (US) - all things fasteners
Mecatechnic (France) - NOS VW parts
Parasol Inc (Canada) - plastic/vinyl paints & dyes
Black Forest Industries (US) - specialty VW parts
Metal Supermarkets (US & Canada) - cut to order metal
Wizards of NOS (UK) - high-end Nitrous components
Bus Depot (US) - aircooled VW parts (that often cross-ref to mk1 parts)
Airhead Parts (US) - same as above
Kinsler Fuel Injection (US) - all things fuel related
) - January 2, 2017

 

Part 138 (I have been fooling around with my braking system, trying to set my rear brake line pressure to the correct level to avoid rear-first lockup conditions without success, and it didn't make any sense to me as I have a Wilwood adjustable proportioning valve in the system. I also wanted to explore ways to continue to improve the responsiveness of the brake pedal - to have it activate as quickly as possible with the minimum brake pedal travel, so I also sourced a 25.4mm master cylinder to swap in replacement of my current 22.2mm MC. This would have the net effect of reducing pedal travel 30% while increasing pedal effort by the same ratio, and since I already prefer running my brake servo vacuum at 50-70% of maximum available vac I can do the swap and maintain the same pedal effort by simply turning up the vacuum (I have an electric vac pump under ECU software control so this is easy to adjust on the fly in the car - I have a panel dial that I can simply turn).

Anyway, I sourced a 3,000psi line pressure gauge with the appropriate adapter fittings to screw into the blanked-off MC ports front/rear and also the bleeder valve ports on the front and rear disk callipers. I first tested the MC and both circuits showed 750psi without servo vac and 1500-1600psi with max vac. Note, I have a custom brake line setup with 1 circuit to the front and another to the rear to accommodate my proportioning valve - similar to many US spec cars.

Next I tested the line pressures at the front callipers and again saw the same 750-1,500psi range. Finally on the rears I saw 500psi at minimum prop valve setting and 1,500psi at full prop valve setting - the surprise was that I realized I had been turning the prop valve in the wrong direction when doing panic brake stop tests.

By reference the factory test settings for VW mk1-mk4 cars is around 1,500psi max for the fronts and 470-510psi for drum rears and closer to 550-700psi for rear disks, depending on the car. The front/rear bias ratio will depend on a lot of factors - the weight bias of the car front/rear, most importantly while under panic braking, and then the type of front and rear callipers or drums - how much fluid volume is required to move the pistons - the piston area x # of pistons will determine the total force applied to the rotors.

In my case I have upgraded to Wilwood 4 piston callipers so the volume of fluid that needs to be moved to get to maximum braking pressure is much higher than for a stock single piston calliper. I didn't do all of the calculations but I think that the 22.2mm MC is a bit small for the Wilwoods and also that the rear bias needs to be fairly low, in the 550psi range.

I'll wait for the ice and snow to melt (Hopefully later in January) and will get back out for some more panic stops with the current 22.2mm MC before swapping it out for the 25.4mm MC) - January 2, 2017

 

Part 139 (I designed a custom 3-axis accelerometer circuit that plugs into my Holley ECU using the analog 0-5V inputs. It uses a smartphone type chip and I implemented some op-amp circuits to modify and scale the output voltage swings to maximize the digitizing resolution of the Holley ECU which seems to use 12 bit A/D converters. I wanted to get to a +/- 2hp power measurement accuracy which is hard to do. First I changed the output from +/-0.3V/g, to +/-1.0V/g for all axis and then implemented an acceleration only output which is positive 2V/g which I will use specifically for engine power measurements. I will also use the Holley ECU input sensor config settings to further calibrate this unit and finally will have access to the diagnostics 'math channels' to allow me to calculate torque and hp from the raw acceleration and rpm data sets.

I also designed a LiFePO4 battery charging management circuit that sits in-between the standard LiFePO4 14.6V charger and my battery - it was needed to cut off the charging voltage once 14.6V was reached rather than let the battery float at that level which would quickly kill it (you need to get the battery up to 14.6V and then let the internal BMS computer to balance the internal cells and then reduce the voltage back to 13.4V). The circuit I designed also has a continuous use setting which will keep the battery within a 13.4-13.8V operating range when I want to use the battery but not over charge or discharge it. The design uses an Arduino CPU - lots of fun and easy to program.

I am in the middle of designing a new A/C evaporator system using about 1/3 of a Ford F150 evaporator core that now has been plumbed with -8 o-ring fittings and fits nicely on top of my ECU, ultimately feeding into the ventilation fan via a plastic shroud that I will fabricate next.

Josh had proudly sourced some OEM German axle assemblies for me but I found that they had some free-play in them which resulted in a bit of 'slap' when going on/off the throttle as that slack was taken up. Rotating the wheels about 1/4" was the total amount of movement but it was enough to make driving a bit annoying at times when feathering the throttle in city traffic. One theory is that I was using the brakes to load the engine when it was initially fired up on jack stands and the axles weren't totally level, causing the power to be transmitted thru the CV joints at an angle - that may have stressed them and worn them? Anyway, I ordered some expensive 500hp rated racing axle assemblies from The Driveshaft Shop in NC and they are superb quality, using CVs that are 40% larger with all components upgraded end to end. There is no free-play in these assemblies so I look forward to installing them soon.

After doing some more reading about the Wilwood proportioning valves I now understand that when they state 100-1000psi adjustment range they are not telling the whole story - their valves can only reduce the rear brake pressure to 57% of the fronts so if the fronts are 1000psi the rears will be 570psi. I did measure around 500-550psi at the rears during the testing above with the line pressure gauges installed but with the extreme front weight bias of my FWD GTI and my grippy rear disks/pads I may need to go lower still - as low as 400psi, so I have sourced a really tiny and cool little prop valve that can lower the pressure all the way to zero if needed and I will put it inline with the rear circuit so I can reduce the pressure even more if I need to. Once I go to the effort of swapping in the 25.4mm master cylinder I don't want to have to re-bleed the brakes yet again if I still experience rear lock-up ... better to take this additional step now while everything is apart) - February 7, 2017

 

Part 140 (I finished the installation of the 3-axis accelerometer in the car and then did a fine tuning of the calibration in software on the ECU such that the sensors now read accurately to less than +/-0.005g for acceleration, and around +/-0.01-0.02g for braking and corning. I still need to confirm that vibration and electrical noise from the ignition system won't reducing the accuracy, but if noise is added to the signal I can always run a smoothing function in the ECU diagnostics and effectively cut out the noise.

I installed the 25.4mm master cylinder and adjusted the brake pedal linkage, adding back one spacer (for a total of 2) between the servo and MC, and setting the pedal position such that the MC engages immediately within the first 1/10" of foot pedal travel. I also installed the mini proportioning valve in series with the existing Wilwood prop valve and then ran system brake pressure tests. It turns out that I had originally installed and set the Wilwood prop valve correctly as re-testing this weekend proved that even when set at the minimum setting, about 550-600psi of rear pressure is still present when the front pressure is 1000-1500psi (which explains why I was experiencing rear lockup).

With the 25.4mm MC replacing the 22.2mm MC, the brake pedal travel is indeed 30% shorter and the force required to stop at a given rate is also 30% higher as expected. The reason for swapping MCs was done mainly to avoid having the pedal travel too far, making heal-and-toe braking into corners for downshifting purposes almost impossible - too much pedal travel puts the right foot at a sharp angle to the throttle making it way too easy to excessively rev the engine. Having 4 piston callipers up front takes more fluid volume to operate, causing the MC piston to travel further, etc., hence the preference for the new 25.4mm MC. And since I had previously decided that I liked less servo vacuum for a firmer pedal feel, all I needed to do to get back to the same pedal feel was to turn up the servo vac 30% and all is well.

The new mini prop valve (Deltrol p/n 10120-40, Speedway p/n 910-31357) allows the rear pressure to be reduced all the way to zero if desired (for RWD burnout competitions this is what people want) so I was sure it would help me with my problem and it did work as expected. With the valve 80% turn off I got to a max pressure of 500psi and it ramps to that pressure over approx 1s so it has a damping effect on the rear pressure when the pedal is pressed which is actually not a terrible thing - if the prop valve is adjusted to the threshold of rear lockup this will soften the effect and reduce the tendency for a sudden change in direction (i.e. the rear of the car swinging wildly around to the front).

I also installed Wilwood E type pads on the front which have about 20% higher coefficient of friction than the previous BP10 type pads - so once they are warmed up to around 250-300 degrees F the fronts will have more braking sensitively than before which may allow me to adjust the rear pressure up higher. When I am doing lots of track laps I will switch to BP20 pads which have the greatest coefficient of friction at temperatures above 800-1000 degrees F and again, I may be able to dial up the rear pressure more again. The idea is to have the rear brakes do as much work as possible to off-load the work the fronts have to do.

I will be switching to the new front racing axles soon which require extended length racing type studs so I went ahead and installed extended length studs in the rear allong with the new Gorilla open backed 'tuner' nuts which are required when running extended length studs - I also had to use conical to ball seat adapters as the 'tuner' nuts are not generally available with conical seats - and I already have to run conical h/w for my Enkie/Hoosier racing wheels and slicks. I think they look decent enough on the OEM VW Snowflakes and they sure are a lot easier to mount/dismount than the OEM bolt system too.

The snow and salt should be washed away by rain over the next week and I may then have a chance to do some road testing to confirm that I didn't add too many spacers between the servo and MC (last time I had 3 spacers and after a few minutes of driving the car started to self brake - likely caused by the brake system warming up and expanding a bit (my tolerances were too tight/aggressive) - February 13, 2017

 

Part 141 (I got the OEM axles pulled out and installed the new 500hp rated axles but it was a ton of work: first the spindles/hubs needed to be pulled apart so the new hubs (larger splines and shaft, 32mm nuts, etc.) could be pressed in with fresh bearings, then I over-extended the axle angles when installing them and had to re-build the inner CV joint on one side as the ball bearings had fallen out, then the inner cer-clip on one side was binding against the axle so it all had to pulled out yet again, and finally it all went back together successfully.

After driving around with the new axles I can say that they definitely have tighter tolerances so all I am now left with is a bit of that on-off-on throttle free play from the limited slip diferential that I will simply have to live with - it is only noticeable during slow city driving in heavy traffic. That diff also whines a bit in comparison to the OEM unit - but I don't really notice the increase in mechanical noise much.

The new 25.4mm master cylinder setup feels great - more pedal effort required but the pedal travel is now minimal so heel-and-toe downshifting will be much easier to do - and I simply like a stiffer brake pedal anyways. I just crank up the electric ECU controlled servo vacuum when I want an easier braking effort. The 2nd in-line proportioning valve has indeed solved my front-rear brake balance problem. Panic stops result in straight line skids now. I will wait for warmer weather with cleaner streets before fine tuning the balance setting (too much salt and sand dust still on the roads).

I did have to back off somewhat on my brake pedal preload - I have a custom linkage that allows me to set the servo/MC preload to reduce pedal travel but I was at the point where there was a bit of self braking once the system was fully warmed up - backing off the brake pedal 1/4" solved that problem and now there is a softer initial brake response for the first 1/4-1/2" of travel which is actually a good thing. I am very happy with the end result

I changed the oil (another fill of the break-in oil) at 300kms and will finally switch over to full synthetic oil at the 600-800kms point. It is likely just in my head but I think the engine runs better with the fresh oil in it.

I did a total of 6 acceleration runs with my new accelerometer and consistently saw over 0.5g of raw acceleration from 5,000-8,000rpm in 2nd gear which is quite something considering that I have the longer final drive ratio gearing installed in the transmission (I can reach almost 120kph/70mph in 2nd gear), so that means I am pulling with about 25% more Gs at 70mph than my old '87 Mustang did with its 340hp engine at 40mph. The GTI feels very alive above 5,000rpm and in fact it feels a little dangerous/unstable - you simply don't want to put your foot all the way into it unless the road is straight and smooth as the car will start to dance around and head into the rubarb if you aren't totally in control of things - you need to hold on to that steering wheel and keep things heading in the right direction. Heaven knows how I am going to handle another 100hp of nitrous on top of this.

It is very easy to convert acceleration data into torque and hp - you just need to know the actual weight of the car and the rpm and wheel diameter and you have a direct measurement of the power being produced at the wheels. You need to perform a coast-down test to determine the losses due to wind resistance and rolling losses and that is all. I have confirmed 200hp at the wheels at 7,500-8,000rpm and 150ft-lbs of torque at 6,000rpm. Using the commonly accepted 20% drivetrain loss estimate for manual transmission cars that is 240hp and 178ft-lbs of torque for a 2.1L normally aspirated engine which actually idles like a stock engine at 1000rpm - that is a rare experience (for cars without computer adjustable cam profiles). I realize now that the above hp calcs from October 2016 were based on the Holley ECU fuel flow tables at 101MPa of vacuum were over-estimating the hp simply because my MAP signal is actually only 99MPa at full throttle, not 101MPa so I never get to the absolute top of the fuel tables in practise ...

Oh, and I just ordered some Sparco EVO racing seats and 4 point racing belts to keep me safe and secure while being tossed around at the track - the stock GTI seats are a bit wobbly and don't really have the aggressive racing-type side bolsters to keep me firmly locked in place and in total control of this wild hare. I'll use the stock seat belt mounting points to fabricate and install a mini roll-bar and seat/seat-belt brace structure, plus I have ordered a pair of GTI seat frames to allow me to fabricate mounts for these Sparco seats that will simply attach to the stock seat h/w in the floor.

I have included the wheel hp/torque measurements for a similar 2 litre ABF motor with the same Techtonics 288 race cams and similar heads and compression, but with the OEM log-style intake system below. It achieved the same torque at the same rpm but ran out of high-end breathing due to the intake manifold, where-as my ITBs allow power to keep building past 8,000rpm. ITBs and careful ECU programming also allow my engine to idle and have excellent part throttle/low rpm drive-ability where-as this other car barely idles and has terrible sounding part throttle response:

http://forums.vwvortex.com/showthread.php?5078261-189whp-153wtq-2.0l-16v-ABF-Info-inside

288 cam, 11.5cr 2L ABF motor with common intake plenum on the rollers at NGP
http://www.youtube.com/watch?v=1YeZNElfsNo

288 cam, 11.5cr 2L ABF motor with common intake plenum at startup and idle
http://www.youtube.com/watch?v=VILRqAkv24I

- February 27, 2017

 

Part 142 (After further thought I have decided to purchase the unique Tech-53 callipers (made specifically for Tech-53 by Wilwood) and replace my standard-issue Wilwood Powerlites as the Tech-53s have 68% larger piston area, which will vasty increase my stopping power relative to brake pedal force, and more importantly will improve my front/rear circuit bias such that I can run without the 2nd proportioning valve.

After a long discussion with Fred, the owner of Tech-53, about my brake bias issues, pedal pressure requirements for a panic stop, etc. it became very clear that my Wilwood PowerLite 4x1.25" piston callipers were undersized relative to the task at hand - in fact they are only 15% larger in total area than the stock single piston callipers so they don't effectively shift enough of the brake bias forward to avoid premature rear wheel lockup. 

Fred is an aerospace engineer who has put in a lot of time into thinking about the lack of properly spec'd 4 piston callipers that are available for mk1 and mk2 cars so he went about negotiating a deal with Wilwood to have some large piston callipers custom made to his specs. They use 1.625" diameter pistons vs the 1.25" diameter pistons in my Wilwood Powerlite callipers, thereby providing 68% more clamping pressure (and therefore braking torque) - and that means that for a given brake pedal pressure the car will stop 68% faster - up to the limit of the tires, with minimal increase in pedal travel. Since I have a huge, race oriented 25.4mm master cylinder, pedal travel and feel will not be negatively impacted. Fred says the 23.8mm MCs are an ideal street match to his callipers and that 25.4mm MCs are awesome on the track - since I like a stiff brake pedal I am pretty sure I'll like the feel on the street as well, given that I am already pretty happy with the way my existing system feels.

Fred also pointed out that the G4 rear aluminum callipers are 2mm larger than the steel G1-3 callipers (38 vs 36mm) so that aggravates the premature rear lockup issue. I am confident that I will be able to eliminate my 2nd proportioning valve now and also be able to dial back the Wilwood valve to reduce the time delay effect in rear circuit pressure build-up.

I have completed a brake conversion table with all of the common after market setups (brake torque, front-rear bias, etc.).

My excel spreadsheet analysis can be found here:  http://www.derekspratt.com/Misc/VW_Mk1_Big_Brake_Conversion_Analysis.xlsx
)

- March 7, 2017

 

Part 143 (We still have winter conditions in the Pacific Northwest for the most part, but there are the occasional days when the sun is out and temperatures are up enough to do some driving/testing. The roads still have a lot of sand on them so traction is limited and the sand gets into the brake system as well ...

My first attempt at driving around the block with the new big piston Tech-53 callipers was cut short by some nasty sounds coming from the front wheel area. I had obviously checked the clearances so I was puzzled about what the sounds were. My inspection found that the control arm ball joints were lose - the 'grade 8.8' bolts were actually stripped and so the ball-joints were barely being held in place. Yikes! It turns out that the crap bolts were imported junk and are now being replaced with OEM/German grade 10.9 h/w. Double-check the h/w on any aftermarket control arm/ball joint combination products that you may purchase ...

Another area where cornering noise was coming from was due to the new CV boots sticking/rubbing each of the folds against each other - by 'lubricating' them with rubber care treatment they became quiet as well. Finally, sand was getting into the brakes causing some intermittent scraping sounds (I don't use OEM dust shields to help cool the rotors on the track).

With all of those gremlins out of the way I was able to do some braking tests: the Tech-53s take about 1" more travel, which makes sense, as the volume of fluid required to push those big pistons is greater, but the force required is a lot less, making the brakes feel very responsive and powerful, which is what I was hoping for. I will look into adjusting the brake pedal linkage again, putting a bit of pre-load on the system - and double-checking that I am not over doing it as in prior attempts to reduce pedal travel. With the large 25.4mm master cylinder paired to these Tech-53 callipers the pedal feel and travel are close to ideal now. The biggest area of improvement comes from re-balancing the front/rear braking bias - I have now fully opened up the 2nd proportioning valve and panic stops in the rain did not cause pre-mature rear wheel lockup so all is well. I will start to back off the reduction setting in the main Wilwood proportioning valve next ...

I need more time to drive in dry conditions, which I should be getting by the end of the weekend so stay tuned for more commentary on this new braking system. I am all smiles for now) - March 13, 2017

 

Part 144 (After tracking down the grinding noises from the front end while testing the system I noticed that the clearance from the outside edge of the rotor to the inside surface of the calliper was minimal on the driver side and there was evidence of some minor contact. I was able to loosen and move the calliper to gain more clearance but decided that for racing thermal expansion purposes that I would increase the gap from 0.020" to 0.070" by milling the rotor down from 10.1" to 10.0" - this still left enough surface area for 100% brake pad contact so there will be no reduction in braking performance. I also had some minor contact between the outside edges of the callipers and the inside surfaces of the 14x6" OEM Snowflake wheels so I have swapped out the 3mm spacers for 5mm spacers.

After bedding the new pads the brake feel from this new Tech-53 big 4 piston calliper system is incredible. I did some brake pedal linkage adjustments such that the pads contact the rotors when there is less than 1/4" of pedal travel so the brakes are now very responsive. I believe that these callipers are a huge advance in mk1/mk2 brake performance/feel and certainly address the prior issue of front/rear system bias - I have not backed off the proportioning valve but will do so later today and do some more testing. Even with the valve at its current setting the car stops urgently with only moderate brake pedal pressure. I also think that the 25.4mm master cylinder is an ideal match to these Tech-53 callipers.

Additional post-video testing results: With the prop valve backed off 2 full turns I was able to get all 4 tires to enter a skid condition together at the same time. Max braking deceleration was almost 1.1g with the street R-compound Bridgestone Direzza-II 185/60-14 tires (when the air and road temperatures were only 50 degrees F) so this little bunny is stopping with the best of them now!

I made the decision to be safe on the race track with Italian Sparco racing seats that will hold me securely in place for improved driving accuracy, equipped with 5 point harnesses to keep me safe if something bad happens (note, I am going to attempt to use a Simpson single anti-submarine lower belt rather than the dual belt Sparco design as I think they are cross-compatible with both cam-lock systems). I received my new racing Sparco EVO seats which are really nice and started the process of cutting up some OEM seat bases to use as a foundation for a 1x1" square tube mounting base for the seats - the idea is to have the convenience of the stock mounting locations and fore-aft adjustability. I am also fabricating a cross-tube to mount the shoulder belts to that will attach to the upper and lower frame bosses for the OEM seat belts. I will likely race with just the driver seat installed - no passenger or rear seats for weight reduction purposes (unless I am showing off and having a passenger on the track which will happen from time to time). I am also fabricating a horizontal extension plate for the shifter as it is too far forward to reach comfortably when held in place by a 5 point harness) - March 20, 2017

 

Part 145 (I had been struggling with poor shifter feel/engagement into 1st gear and so I set about disassembling the shift linkage in order to step-by-step find out where the problem area was. The transmission selector lever itself had a nice positive feel and clean engagement of each gear but I found that something in the linkage was resisting full movement into the 1/3/5 gear positions. It turned out that the rubber ball lever end wasn't moving smoothly and upon closer inspection I could see that the metal rod portion of the rubber ball lever was binding on the metal bracket that it is inserted into - and this was caused by the shifter rod being at the wrong angle as it entered the positioning bushing/bracket. So I pulled the shifter rod out of the car and bent it about 7 degrees about 8" back from the end and it was then perfectly parallel to the black mounting bracket assembly and positioned the metal bracket right in the middle of the rubber lever arm. I was worried that my 0.040" metal shim inside the metal bracket was causing binding with the rubber ball but once everything was aligned properly and greased up, the rubber ball rotated smoothly and didn't bind at all. With a 1/2" lengthening of the upper ball-joint arms to re-align with the new setup, everything was tested and then re-torqued into place. The result is 100% improved shifter feel and perfectly positive engagement in every gear. I am in shifter heaven now) - March 21, 2017

 

Part 146 (I finished the fabrication of the seat mounts for the new Sparco EVO racing seats using the mounting flanges and legs from a junker set of OEM seats - they worked out very well - a little lower position than the stock seats and full adjustability of fore/aft position using the OEM mechanism and slope using some bolting options with the Sparco mounting flanges. Should be sweet!

I don't have a tube bender so Ted at JetFab in Richmond, BC will be fabricating the bolt-in roll hoop which will use the stock seat belt mounting points to secure it to the body of the car. The hoop will have the cross-bar for the shoulder harness mounting points plus a central camera mount. When it is complete I will send the seats and hoop out for powder coating.

I am also fabricating a rear shock tower cross-brace that also connects into the rear bumper mounts which will be needed as a mounting location for the nitrous and air tanks (the 4500psi air tank pressurizes the nitrous bottle to 925psi and holds it exactly at 925psi using a regulator rather than relying on a heater which doesn't keep the nitrous pressure constant while it discharges). I don't think the brace will actually have much effect on stiffening the chassis further as it is already welded up with a sub-frame, cross-bracing and will soon have the roll-bar ...

I was complaining about the Walbro 393 fuel pump making a nasty noise so I talked with Kinsler Injection which supplied me the whole fuel injection system and most of the engine sensors, wiring harnesses, etc. and they said 'check your 25 micron intake and 10 micron output filters' so I did and found the intake filter completely plugged up with a nasty black sludge which looked like jello! The intake filter is a steel mesh so I cleaned it while I replaced the 10 micron paper filter and also replaced the pump as it had been damaged from the stress of pumping against such a massive restriction. The black sludge could simply be from old gas sitting in the tank for months at a time (if that is true it is actually from bacteria which is always present in fuel, more in ethanol enhanced fuels which also are hydroscopic and suck up water). There is also the possibility that my dumb attempts to seal-up my old fuel tank level sender with silicon sealant (since replaced with a new sender and o-ring) may have caused this as the silicon dissolved in the fuel. Anyway, I will keep an eye on this issue and service the fuel system filters more often. Next time I will do this when the tank is almost empty, rather than completely full! It would have been smart to have installed a fuel tank line valve too - I rely on hose-end plugs to service the fuel system.

Finally, I have put 1100kms of mountain driving on the GTI so far with 700kms of that this last week alone - 3 days of driving to Whistler, with 25,000' of total vertical climbing. I switched out the Joe Gibbs break-in oil now for their 10-30W hotrod conventional oil which contains lots of ZDDP zinc to protect my solid lifter cams/tappets which are under extreme pressure from 8,000rpm and high lift racing cams and springs. I will switch again to their 20-50W oil when I get to the track in May. I may eventually switch to their synthetic oil with ZDDP added to it after 5,000kms.When decelerating from 5,000rpm the MAP signal drops to 17MPa which is the equivalent of 25" of mercury vacuum so the rings on the pistons have sealed nicely
) - April 2, 2017

 

Part 147 (For over 30 years now I have been measuring vehicle performance using accelerometers and then using either my own programming or off-the-shelf software programs to further analyze and predict performance, helping to choose rpm shift points, gear ratios, wheel and tire combinations, etc.

For this project I again used accelerometer measurements, along with fuel flow data from the Holley ECU to confirm the engine torque and hp curves and I loaded that data into Excel and added nitrous in varying amounts to see what kinds of torque/hp curves could result and then fed that data into a drag racing simulator, Drag Racing Pro v2.0, and adjusted all of the vehicle and driving info to produce realistic 0-60mph and 1/4 mile charts and graphs, using my newly acquired Hoosier 225/50-15 DR2 drag radials on 15x8" rims, using my excel data. The results are as follow:

Engine only (no nitrous): 0-60mph 4.1s, 1/4 mile: 12.3s @ 112mph

Variable nitrous to produce a flat 200 ft-lbs torque curve: 0-60mph 3.8s, 1/4 mile: 11.8s @ 117mph

60hp nitrous at all times: 0-60mph 3.5s, 1/4 mile: 11.5s @ 120mph

80hp nitrous at all times: 0-60mph 3.4s, 1/4 mile: 11.3s @ 123mph

The simulator shows that a FWD car like the mk1 golf is severely traction limited due to the weight on the driving wheels being only 50% during acceleration, vs a RWD car that would have 80+%. So even with slicks and a solid trans mount and stiff springs the best I can hope for is a 1.9s 60' time and a little over 0.81g of acceleration in 1st gear. 

I already know that 1st gear on the motor alone with sticky street tires is a 50-60% throttle gear, but with nitrous even 2nd gear with slicks becomes a problem. It will be fun to get the car on the track soon and find out (May 12th is the 1st local track 'test and tune' day that I will be ready for).

Ted/Jetfab has the roll-bar finished now so it is out for powder coating. Seat mounts are done too so all safety gear that I want to have for track days is now 'good to go'
) - April 12, 2017

 

Part 148 (I sourced Hoosier 225/50-15 DR2 slicks and mounted them on Enkei 15x8 RP1 racing rims and used 10mm spacers to clearance the struts - if I hadn't lowered the car so much they would have fit perfectly but in my case I have also sourced 1" rubber spring spacers to lift up the front end and provide more of a fender gap. 

I also sourced a solid rear transmission mount which is something a lot of VW mk1 drag racers have recommended - it keeps the engine from rocking back and forth, improving traction on the track.

I have sourced the required components to get a brake cooling/ducting system put together - something I will get done before heading out for a road course track day ...

On the electronics side of things I have put together a full video recording system using the 'Harry's Lap timer' App on my iPhone, plus a high frequency bluetooth GPS, a bluetooth OBD/Canbus transmitter, and a Hero4 GoPro - mounted to the middle of my new rollbar - this will allow me to record HD racing videos complete with embedded track location/performance data.

I got my shifter extension built and love it ...

My rollbar was powder painted and installed, and I also mounted one of the Sparco EVO seats to my new seat frames and installed the harnesses - it all looks so 'trick' now with the other seats removed.

I fabricated an aluminum 'X' brace for the rear of the car which holds everything in position for road racing and also works nicely as an angled mount for the nitrous and air bottles - it still needs to be painted though.

This Friday is the local Mission RaceWay 'test and tune' day but the weather does not look promising. Possibly later in the day the track might dry out but I am not sure it will be worth the cost and effort to go out and sit there watching the rain come down, waiting, waiting for the track to dry out (something I have done many times) - It may be May 26th for the next T&T day :(

Finally, I cleaned out the intake fuel filter again and found some more of the black gunk in it - I still believe it is the remaining crap from the silicon sealant I had previously used to seal up the fuel sender - I will check the filter again in another month. I also purchased a combustable fuel vapour sniffer and used it to confirm that my stainless fuel lines are releasing vapours - and this has been confirmed by the manufacturers of stainless/rubber lines - they don't fully keep the fuel sealed up and cause a slight odor. Strange as I think that is a bad design/material spec. I will likely rip out all of the fuel lines and replace with stainless/teflon lines at some point down the road as I don't like my GTI smelling like gasoline when I go into the garage) - May 9, 2017

 

Part 149 (I spent a few hours at Blitzkrieg Automotive in Vancouver today with the GTI axle-bolted to their Dynapack dyno today and it was really a fun and worthwhile experience. The traditional roller-type chassis dynos have some potential variables with rolling friction that can vary depending on how tightly the car is held down onto the rollers while the Dynapack unit not only removes this variable (and any tire slip) but also securely holds the car in place without risks. The units are super expensive ($150,000) but their accuracy and repeatability are 1st rate. I was able to look for 1 and 2hp improvements over a range of parameters and slowly find missing power. We did about a dozen pulls covering fuel/air ratios, timing, injector end angle (the point in time when the injectors stop firing relative to the compression stroke), removal of the air box and filter and replacing the long intake trumpets with shorter trumpets. We were also going to test the nitrous system but the nitrous ECU enable line wasn't triggering the system properly so I will have to do this at the track and on the road next week (I found the problem later - Holley has a naming convention bug with the nitrous enable input that I had to work around by creating a touch-screen 'master nitrous enable' and then a ''stage 1 enable' using my dash mounted switch - I am pretty sure it will work now). Here are the test results:

191 hp @ 7200 rpm, 150 ft-lbs @ 6100 rpm - 13.0:1 A/F ratio, 26 degrees of total timing

192 hp / 151 ft-lbs - 13.2:1 A/F

194 hp / 151 ft-lbs - 13.4:1 A/F (13.6 saw a drop in power so this is the ideal A/F)

196 hp / 150 ft-lbs - 28 degrees of timing

197 hp / 150 ft-lbs - 30 degrees of timing

198hp / 150 ft-lbs - 32 degrees of timing (I did not attempt to advance the timing any further)

198hp @ 7200 rpm, / 162 ft-lbs @ 5400 rpm - no air box or filter

204 hp @ 7200 rpm / 164 ft-lbs @ 5400rpm - shorter intake runners/trumpets

Leaving the injector end angle at 0 degrees (start of compression stroke) was the default ECU setting and made the most power.

The big story was the removal of the air box and air filter - it increased the engine torque dramatically over a wide area from 5000-7000rpm and moved the torque peak down 1000 rpm - this will improve the overall acceleration 'area under the curve'. On the street it isn't practical to run unfiltered air into the engine (it will ruin it over the long haul) plus the noise from the ITBs is massive - you can hear the engine accelerating 10 blocks away with the air box removed - it is much louder than the exhaust system.

Dynapack dynos are reliable and conservative power measuring devices - to calculate crankshaft power add back the estimated 15% loss which brings this engine to 240hp which agrees exactly with my accelerometer testing last month so I will simply use my accelerometer testing for the nitrous system benchmarking next week. FYI, my 2L GTI engine produced the most power these guys have ever measured on this dyno of this size and type of motor - no other 2L 16V NA engine has exceeded 200hp before so they told me I have a 'sick' motor ...) - May 19, 2017

 

[Special thanks to Kevin Young, a fellow vw mk1 enthusiast, for helping me out at the track all day - it would have been very difficult without his assistance]

Part 150 (I drove the GTI out to Mission Raceway last Friday and bolted on the Hoosier DR2 225/50-15 slicks with 10mm spacers and 1" rubber coil spacers to give me barely 1/2" of needed clearance to the wheel wells - and they didn't rub even after lowering to 15psi and doing 5 passes on the strip. Yeah!

The s/w simulator, when loaded with the dyno test results, indicated that when fully dialed in the GTI should get close to 12.3s @ 112mph w/o nitrous, and around 11.5s @ 123mph with 80hp of nitrous. I ran 13.8s @ 104mph. What happened? Lots. I'll be back again on June 16th, weather permitting, which is the next 'test and tune' track date.

Lessons learned from day 1 at the track:

1. I need to increase the rev limiter from 8000 to 8300rpm (I was hitting the rev limiter in each gear for 0.25s before shifting)

2. Install that solid transmission mount to stop the wheels from loading/unloading all the way thru 1st gear

3. Do a bigger ‘proper’ burnout after going thru the water box as the tires were still wet and not gripping properly – drive thru the box and start the burnout on the other side, keep them spinning until there is some smoke

The total damage relative to my software simulated runs...

I ran a 2.3s 60' time rather than a best possible 1.8-1.9s time (0.4s delta) - looking at the ECU datalog it is clear that I wasn't even at 50% throttle for most of 1st gear - and the tires were still spinning like mad, plus the time from throttle off in 1st and back on in 2nd was over 1s ... this kills ET and mph as the car is eating up track distance without any acceleration - I needed only another 30' of track to reach 8000rpm in 3rd which is 111mph with the larger diameter slicks ...

I shifted too slowly each time (0.5s lost total), I hit the rev limiter for about 0.25s in each gear 

I ran 13.8s @ 104mph and it is easy to see that the GTI indeed has the potential for mid 12s 110mph+ time slips on the motor alone ... I need more seat time at the track for sure - this isn't as easy as going to a chassis dyno (it requires skill that I currently lack). Hmm.

And the nitrous wasn't working - I will need to debug the wiring to the solid state nitrous solenoid before heading back to the track. Good thing the nitrous wasn't working though as it would have just made things uglier at the track - I need to dial in the car w/o nitrous first) -
May 30, 2017

 

 

Index of Project web pages:

Project Overview, Goals & Specs

The Ultimate 83 GTI is now For Sale

Project Car Initial Condition
Chassis Development
Bodywork & Paint
Suspension, Steering & Braking Systems
Engine, Oiling, Cooling, Transmission & Exhaust Systems

Electrical, A/C & Fuel Systems
Interior
Performance Validation
Final Street Trim Conversion

VW Vortex thread on this project

Videos # 001 - 049 (Feb 2013 - May 2014)
Videos # 050 - 099 (Jul 2014 - Sept 2015)
Videos # 100 - 149 (Sept 2015 - May 2017)
Videos # 150 - 181 (May 2017 - Dec 2019)

My original 1983 Rabbit GTI (owned 1983-1987)

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