Project RWD VRT Mk1 VW Insanity (AKA: The Black Hole)The History
For those of you familiar with the SpitfireEFI family, or have ever come within shouting distance of me, you have probably heard a thing or two about the crazy idea I've had for a rear wheel drive, mid engine, turbo charged VR6, Mk1 Golf. The project has been rolling around in my head ever since my previous Rabbit project was finalized and I finally internalized this fabled quote from a former professor:
With this 'nothing succeeds like excess' mantra in mind, I set out on the path less traveled, with my VISA in one hand and a sawz-all in the other. Each day at the shop is fueled by the vision of leaving the driveway sideways, smoking the rear tires of an insane Mk1.
The first order of business was to fit a roll cage to brace the front half of the car. The cage will stiffen the chassis, provide structural ties for the rear engine and suspension supports, and protect the occupants if the worst should happen. It was also important to get the majority of the cage in first to provide stiffness after the pending hole was cut into the rear. Due to the complicated bends required (and my lack of equipment and experience) I figured this task would best be left to some pros. I dropped the stripped down shell off at DK Diesel and Offroad - a local shop operated by a friend of a friend - and showed them what I was looking for in a cage.
While the Rabbit shell was out of my garage, I took the opportunity to fill the space with another car. Acquired for its strong VR6 heart at a decent price, the '93 VW Passat was wheeled into the 'operating room'. With surgical precision the engine, subframe, axles, control arms, and some other miscellaneous suspension bits were removed. Eventually I found out the recipient would reject most of these parts , but the exercise proved a valuable learning lesson. Though the engine beat the pavement as good as any, it's getting long in the tooth ? especially considering the slim sprinter it will be transplanted into. Thus, down the road it will go back under the knife for some serious mechanical enhancements.
At long last the front half of the roll cage was finished and the Rabbit was dropped off safe and sound at the shop. The chassis was propped up on four jack stands and everything in the back was removed ; the wheels, suspension, torsion beam, and fuel tank were all stripped off and cast aside. With much trepidation I set about making some room in the rear. The sawz-all make quick work of the thin sheet metal surrounding spare tire well and rear seat area. Within minutes, a gaping hole was all that remained of the area that had hauled groceries and loved ones over innumerable miles for almost 30 years.
It's quite intimidating to stare a gaping hole in the back of your project car with no idea where to start. I decided the best strategy would be to reuse a stock subframe and simply translate the entire drivetrain setup from the front of the car to the rear. The stock subframe will properly locate the control arms and wheel hubs in relation to the engine.
Using the rear axle mounting studs and various other features as reference, I got an idea of where the subframe needed to be placed. Holding it in place with an engine hoist and jack stands, I estimated where it should be placed in relation to the wheel well so that once everything was installed the wheels would be centered at the correct ride height and track true. In order to get the proper control arm geometry at the desired ride height, the subframe needed to mount 1.5in below the frame horns. I made up some quick mounts using some angle iron and a few spare bolts. With these mounts tacked welded in place, I set about fabricating the rear subframe mounts.
With the subframe secured and located by the front two mounts, I started reinforcing the rear. I welded plates on each side of the frame horn to provide a solid landing pad for the rear brace. The plate was fitted between the bolt holes for mounting the rear bumper; I hope to still be able to mount a small euro bumper when everything is finished up. The plates had to be cut in the center and bent slightly to follow the split contours of the frame horns in that area. Next, a sturdy length of rectangular tube was cut and clearanced to fit between the two plates and tacked in.
With the rear brace in place, support tubes were fabricated to provide a mounting location for the rear of the sub frame. The cuts and angles on these tubes were extremely challenging considering I had never done this kind of fabrication before. After a few nights of frustrating failures I called in a few experienced friends to show me how it was done (thanks Kirk!). In short order we had the diagonal braces in place. After test fitting the subframe (it fits!) we added additional supports to the center of the rear brace to support the heavy side loads these mounts will be subjected to. A newly acquired tube notcher helped simplify the process immensely (thanks Aunt Alyce)!
Excited by all the progress lately, I decided it was time to test fit the motor. Unfortunately, the motor will not fit in through the back hatch, so instead of lifting the engine in, we lifted the car and slid the motor underneath. With the shell steadied on all four jack-stands, the hoist was maneuvered into position and the engine raised up and back onto the subframe's engine mounts. With the engine sitting in the car for the first time I got a much better idea of where everything would be positioned. The top of the engine is just below the window line, and leaves plenty of room behind it for a sizable turbo and the associated exhaust components. There is ample clearance and access room in the front too. It became apparent that I would have to notch the right hand frame horn to clearance the crank pulley and bolt.
The test fit also showed that the front motor mount lined up almost perfectly with the preexisting mounting points for what used to be the rear beam.
Seeing the engine suspended in the back of the Rabbit was inspiring and fabrication efforts were redoubled. The first order of business was to notch out the frame horn for the crank pulley. This was accomplished in short order with a combination of sawz-all and grinder. Now that the engine could be properly positioned in the bay, I could see exactly where the front mount needed to be.
I started with two short pieces of angle-iron and marked out two holes on each for the mounting studs. The rear edge of each needed to be clearanced with a slight angle to be able to clear the inner part of the wheel arch. With the brackets aligned over the studs, a length of rectangular tube was cut to fit between them. Once the length was just right everything was tacked together and test fit back on the chassis.
Unfortunately all the pieces didn't fit back together again. The oil filter assembly on the engine interfered with the newly created brace mounted to the car. A remote filter was on the list anyway, so the offending component was simply removed. I also found a mounting ear on the transmission bell-housing was dangerously close to the front brace. To clear it, a section of the brace was cut out and a covering plate welded back in.
With all the pieces fitting properly now, I took some measurements for the front mount itself. Using cardboard scraps for mock up, I designed a folded trapezoidal mount to bridge the gap between the motor and support beam. A circle was cut into the front of the mount to allow tool access to the mounting bolt. The front mount will be ? for all intents ? solid, however a thin layer of rubber will be placed between the two mating surfaces to help isolate the vibrations and distribute the loads.
With all the recent progress this project has gathered a lot of momentum and been extremely exciting. Unfortunately, all that must be put on hold because the company is sending me to Europe for 6 months. I'm sad to leave it, but I think the momentum will carry through the break and I'll return with the same vigor.
Before I left, I made it a goal to get the car moved across town back to my garage. This meant getting it rolling on four wheels - a task that seemed like a tall order one week before the deadline. The strut towers still needed to be constructed and all the suspension sorted out. However, by shuffling around some priorities and getting huge amount of support from friends, the Rabbit was finally sitting on four wheels and across town at my house with only hours to spare.