Last updated: October 21, 2014

Project "Ultimate 1983 Rabbit GTI"
Engine & Transmission ...

 

Index of Project web pages

Project Overview, Goals & Initial design specs
Project car initial condition
Chassis development
Bodywork & Paint
Suspension, Wheels, Tires & Braking System
Engine & Transmission

Electrical & Fuel System
Interior
Performance validation
VW Vortex Thread on this project
Videos
My original 1983 Rabbit GTI (owned 1983-1987)

 

I was always interested in Callaway turbo kits for my original GTI and came close to acquiring an 84 GTI with one of these kits installed on it. But turbo kits add weight and they change the engine's free revving characteristics which were perfectly matched to the 5 speed trans. Like many other people I feel that the ultimate mk1 GTI has either heavily worked over 8V heads or carefully massaged 16V heads (keeping an eye on mid-range torque), a 2L block, and a close ratio 020 transmission. So I contacted Josh Arnold at Techtonics Tuning in Portland, Oregon, (who did the engine development work at his own business with his dad, Mark (Mark's VW Service, Amity, Oregon) and asked him if he would do the ultimate 16V buildup. He started sourcing the components and building up the motor in late November 2012 and completed it in March 2014 (for more info on Josh, TT, and a similar project, see this VWVortex thread).

We choose a VW/Audi ABA-ABF hybrid short block (used in the mk3 VW/Audi 93-97 16V 2L cars producing 150hp) and Josh built a 2092cc 16V motor around an ABA block with ABF internals: a new VW OEM 95.5mm stroker forged crank, custom forged rods, 83.5mm 12:1cr custom pistons and a lightened/balanced intermediate shaft. The heads are high velocity/turbulence 9A 16V (used in the mk2 VWs) with +2.0/0.5mm over sized 34.0/28.5mm valves/seats, 5.5mm super small intake stems, tapered guides, etc. - with a full 'stage 3' head treatment. And the cams are TT 288 degree solid lifter (DLC coated) race profiles to deliver moderate midrange torque and a targeted 240hp peak at or slightly above 8000rpm. And to top it off we are using an individual DTH (direct to head) ITB intake system from AT Power, the Holly HP EFI system (with 8 injectors - 1 set for low RPM/part throttle, and the 2nd set for high RPM/full throttle), and a dry flow nitrous system to add mid range torque and 60hp at 8000rpm for a total of 300hp).

To fit in the ATPower TBs and their long curved 280mm individual intakes, I am designing a custom radiator that tucks in behind the grill. German Transaxle of America has built and delivered to Techtonics an 020 AGB 2Y (mk3) close ratio transmission (same exact 3.45/2.12/1.44/1.12/0.91 1st thru 5th gearing as the original 020 2H trans but with a 3.67 final drive ratio rather than the earlier 3.94 ratio) with a Quaife differential and many other performance goodies. It will be shifted via a Techtonics shift kit. HD rubber engine/trans mounts have been selected to provide a performance oriented mounting system without undue harshness or vibration. A high performance 210mm clutch with lightened flywheel will be used. The car will cruize at 70mph at 3465rpm and will be at 150mph at 7500rpm in 5th gear.

High quality race prepped 100mm OEM CV joints and axles have been fabricated/assembled as well.

 

Initial Engine Assembly photos - taken at Mark's VW Service and Techtonics Tuning - Feb 15, 2013

 

Josh Arnold - engine builder extraordinaire

 

The VW (mk3) ABF block, (mk2) 9A cylinder head and 83.5mm forged piston

 

95.5mm stroker VW forged crank and rods prior to lightening and finishing

 

11.5:1cr forged 12% silicon (low expansion) forged piston

 

VW 9A 16V cylinder head

 

Combustion chambers with 34.0/28.5mm oversized valve seats, prior to blending, valve unshrouding and bore matching

 

Intake ports (left unpolished to foster mild turbulance)

 

Tapered 5.5mm intake valve guides and blended 34.0mm (+2mm) valve seats

 

Polished exhaust ports, tapered exhaust valve guides, 28.5mm (+0.5mm) valve seats, port matched to 1.75" primary exhaust header tubes

 

Comparison of 5.5mm stem x 34.0mm diameter intake valve with stock 7.0mm stem x 32.0mm diameter intake valve and retainers

 

Comparison of 28.5mm diameter light weight/undercut exhaust valve with stock 28.0mm diameter exhaust valve

 

Techtonics HD valve train components

 

Techtonics factory/warehouse tour ...

 

 

The AT Power Individual Throttle Body intake system for the 2092cc stroker VW 16V ABF/9A motor

 

Photos taken March 12/13 2014 when the engine was completed:

 

NOS Wizards Quadranoid, a dry flow nozzle, and small ID plastic tubing - May 9, 2014

 

EAA Engineering's Serpentine Belt System, Fluidamper, and Denso Racing Alternator (all put together with clear anodized billet aluminum CNC mounts) - a must use system to clear the ITBs - May 9, 2014

 

Now that I have ordered the Davies Craig electric water pump and digital controller it is time to prepare the OEM water pump by cutting off the impeller, aux water return ports (which will be tapped and plugged), and smoothing the interior for its new function as a passive entry way into the block from the outlet of the EWP - August 17, 2014

 

Rough positioning of the Techtonics stainless custom 1-3/4" headers and 2-1/4" exhaust system plumbing (note, we are keeping the pipe size at 2-1/4" because this is the size that TT says has proven to produce the most power in normally aspirated cars: 2-1/2" is only suitable for turbo engines) - September 8, 2014

 

After a lot of machining and fiddling around I managed to complete the front cylinder head coolant outlet flange that is required to clear the ITBs and associated linkage, nitrous and vacuum lines, etc. - September 14, 2014

After speaking with Techtonics about the exhaust system clearance issues I cut off all of the tunnel flanges and bolts, filled, sanded, primed and painted it all so now there will be nothing hitting the pipes. I also sourced a really nice and small Vibrant stainless resonator that will be welded onto the back of the flex coupling: this way I will havee 2 resonators plus a muffler so that I can make 'quiet power' which is my goal - September 14, 2014

The shifter housing after cleaning it up and epoxy painting it - September 14, 2014

 

I have been busy using my Caswell Zinc/Copy Cad plating system to rescue all kinds of brackets and bolts since I have not been able to complete my brake lines until the MasterCool flaring tool arrives (ETA tomorrow). I plated the metal objects that were OEM plated and stopped there but for those parts that were originally painted black I first stripped them down, acid etched, plated and chromated them to provide an extra measure of protection before painting - September 23, 2014

 

This has been a big week with lots of progress. Below are photos of the plating/painting of the headlight housings, the various motor mounts and inserts/shift linkage, etc going into the car, and the heat shielding. Not shown is the braking system which is now complete and the Quaife steering rack which is also now complete (see other web page) - September 28, 2014

 

The rear end is complete and torqued to spec, the steering rack and shifter linkage is now mounted in the front and now I am getting ready to flip the chassis upright for the last time - October 6, 2014

... and the 020 2Y German Transaxle of America transmission with Quaife LSD is sitting here, waiting for the custom clutch/pressure plate which Josh says will ship to me later this week ...

Quaife transmission differential ...

There is an excellent VW transmission specifications reference site at http://www.rabbitgtipage.com/transmission.html

 

The engine is now getting very close to mating with the transmission, and installed into the chassis- hopefully this weekend. Below are some before and after photos of the cam position sensor, turning the OEM unit from a 4 position sensor to a simple TDC #! sensor - October 21, 2014

 

 

Index of Project web pages

Project Overview, Goals & Initial design specs
Project car initial condition
Chassis development
Bodywork & Paint
Suspension, Wheels, Tires & Braking System
Engine & Transmission

Electrical & Fuel System
Interior
Performance validation
VW Vortex Thread on this project
Videos
My original 1983 Rabbit GTI (owned 1983-1987)

 

 

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