Project "Ultimate 1983 Rabbit GTI"
Overview, Goals & Initial design specs ...
Index of Project web pages
Project Overview, Goals & Initial design specs
Project car initial condition
Chassis development
Engine & Transmission
Electrical & Fuel System
Bodywork
Paint
Interior
Performance validation
VW Vortex Thread on this project
Videos
My original 1983 Rabbit GTI (owned 1983-1987)
Background
I have thought long and hard about the cars that I have owned and which ones meant the most to me, and this 1983 GTI has to take the cake. It was designed and built in an era when electronics and computers were not yet taking over automotive design: roll up windows, A/C delete, no ABS brakes, no air bags, small/compact (2' shorter than my Prius but holds the same # of people and luggage!), light (1800lbs after the project is complete), truly tossable/agile, and fun, fun, fun. And yes, I was 21 years old and this was my first new car, and the one that I dated and married my wife Cheryl with (we took it on our honeymoon).
I have owned a 505hp AMG Mercedes Benz, a 1300hp street legal 67 Chevelle, and have built and raced a pro-stock dragster, but this little car, with its original 90hp 4 cylinder engine was one of the sweetest rides I have ever experienced. But I was eager in 1987 to get behind the wheel of a rear-wheel drive Mustang and so I said goodbye to my love and it has now been almost 30 years and I have come full circle. And this time I have the time, money and motivation to make this car the ultimate mk1 GTI, from my perspective.
Specs for this car
Engine/Trans
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 is actually doing 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 (for more info on Josh, TT, and a similar project, see this VWVortex thread).
We choose a VW/Audi ABF block (used in the mk3 VW/Audi 93-97 16V 2L cars producing 150hp) and Josh is now building a 2092cc 16V motor around a new VW OEM 95.5mm stroker forged crank, complete with late model light weight forged VW OEM rods, and 83.5mm 11.5:1cr 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 will be 288 degree 'sport' profiles to deliver moderate midrange torque and a targeted 240hp peak at or slightly above 8000rpm. And to top it off we will use an individual DTH (direct to head) TB intake system from AT Power, the Holly Dominator EFI system, and a dry flow nitrous system (which will be programmed to turn on at 75% of full throttle to add 30ft-lbs of mid-range torque at 3000rpm and progressively taper off to 'zero' nitrous by 6500rpm to provide an over-all win/win torque curve that matches the ABF profile cams for mid-range torque but allows for strong peak power at or above 8000rpm).
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 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 Sachs 210mm clutch with lightened flywheel will be used.
High quality race prepped 100mm OEM CV joints and axles have been chosen as well.
The AT Power Individual Throttle Body intake system for the 2092cc stroker VW 16V ABF/9A motor, Quaife transmission differential ...
Suspension
With the help of Tom at Essex Distributors I decided to revisit my past and purchased Bilstein race struts (p/n V36-0059 & B46-0657-H1) and H&R race springs with DSX 15mm drop spring perches to give a nice moderate 1.5" lowered ride. Given that the suspension components are pretty stout, I have selected Febi-Bilstein HD rubber upper strut/shock mounts to provide a little 'give' and keep the car from being too harsh, on Tom's recommendation. I will run w/o a front sway bar for now, given how stout the Bilstein race struts and H&R race springs will be, and will have a retro 25mm Neuspeed rear sway bar.
The new OEM steering rack will be mounted with OEM rubber bushings (again, to keep steering wheel feel vibration free, thanks to a tip from Josh at Techtonics Tuning) while the new control arms have poly bushings at the moment (I also have 2 sets of different hardness rubber bushings in case I don't like the feel of the poly). The rear axle beam will have race metal bearings from SCCH.
Look at the size of the Bilstein race strut piston - massive!
Brakes
In the spirit of keeping the unsprung weight to a minimum, I have worked with a local firm, Momentum Motor Parts, to source a complete, state-of-the-art, and super light weight braking system that includes 10.1" front rotors, drilled/slotted with light weight Wilwood 4 piston calipers (saving 5lbs of unspring weight) and aggressive sport pads, have been chosen in combination with Scirocco 16V rear disks/calipers, and the companion 22mm master cylinder and proportioning valve, plus s/s brakes lines.
Chassis
Special attention is being given to the chassis development with extensive bracing and structural stiffening elements being added: a front engine mount brace, triangulating in the strut towers to a firewall brace and a front fender/cross member brace, adding a 4 point cross brace to the lower control arms, designing a removable x brace between the rear shock towers, subframe end-to-end square tube connectors, etc. The goal is to eliminate chassis flex end to end. The trick is to hide all of this bracing and keep an OEM look everywhere except in the engine compartment. I will post lots of photos as this progresses.
Some of the German Klokkerholm OEM quality replacement sheet metal panels I will be using ...
Wheels and Tires
I will have 2 sets of wheels - a fully restored set of original VW OEM 14x6 Snowflakes with 185/60-14 sport tires, and a set of ultra-light (9.9lbs - saving another 5lbs of unsprung weight for a total of a 10lbs savings per wheel with the Wilwood calipers) 15x7 Enkei race wheels with 205/50-15 DOT legal race tires. The look I am after is old school - not the current fad of using 8" rims and stretched 195 tires.
Enkei RPF1 Racing Wheels ...
Interior
While the original GTI midnight blue seat fabric was in generally good shape, I took the approach of getting SMS Fabrics to custom make all new OEM spec GTI seat fabric material and I am getting the seats, front and rear, completely re-built with new bushings, foam and fabric. I will also install deluxe new OEM looking carpet and headliner. The dash looks pretty good but I will take care to make sure every inch of the interior looks stock and mint. That said, there will be some minor trick additions: a hidden (in the 1 DIN stereo location) Clarion VZ401 flip out 7" LCD monitor audio control unit and a killer audio system using Boston Acoustics speakers, hidden in the stock speaker locations, with the addition of larger drivers under the dash and in the trunk area. Gotta have state-of-the-art sound and Bluetooth smarkphone calls and wireless audio streaming capabilities ...
I am also looking into building a very trick fully electronic A/C cooling system if I can keep the weight and the complexity under control. Stay tuned.
SMS 'OEM' VW Rabbit GTI Midnight Blue fabric ...
Clarion VZ401 Audio Head Unit, Boston Acoustics S35, S75 Speakers mounted in stock locations, 6x9" speakers hidden under dash and in the rear, and a 10" sub-woofer hidden in spare tire well with amplifiers (I will keep the LCD hidden unless I need to program it) ...
Exterior
The exterior will be 100% OEM stock looking. I have sourced new OEM GTI badges and moldings all around and it should look show room new when this car hits the road. I will convert my garage to a top-notch paint booth and will personally perform a full concurs paint prep, spray, wet sand, etc. process to create a perfect, orange-peel free result (similar to my 67 Chevelle prep/paint job which cost me close to $20,000 15 years ago ...)
*** under development ***
Index of Project web pages
Project Overview, Goals & Initial design specs
Project car initial condition
Chassis development
Engine & Transmission
Electrical & Fuel System
Bodywork
Paint
Interior
Performance validation
VW Vortex Thread on this project
Videos
My original 1983 Rabbit GTI (owned 1983-1987)
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