Legal spirited driving on public roads does not give one the complete information necessary to evaluate any car's full performance capabilities. Street testing of my R28 only allowed me to reasonably test: the full engine power band in lower gears, the action and feel of the steering, clutch and transmission, the ride quality, dry and wet-weather grip, as well as low speed handling and braking, and I only managed one small traffic ticket. Sorry officer! The results were extremely pleasing and compared well with both, my own performance expectations for my R28 Project, and subjectively with the many reviews I had read about the US spec R32. But finally after 6 months of "My R28 Dues", it was time to take this car to the track. I had been as patient as one could be waiting for this day, as it would be the ultimate test for my "Canadian Concoction R28".
At the Track:
It was a beautiful warm sunny Saturday morning out at my local road course, Race City Motorsport Park in Calgary, Alberta. The event was a late summer (2004) lapping day with the car club I belong to, the Calgary Exotic Auto Group. During our eight or so events each year, members run everything from Acuras to Porsches, and Vipers to ....well...uh.... Volkswagens, on the Race City road course. My usual "weapon of choice" is my 1987 Porsche 911 Carrera Coupe with a few minor mods, but not on this particular day. Fluid levels were checked, brakes were bled and inspected, and regular cold tire pressures were increased and at the ready. Tentatively, I pulled out on to the track for the first time with my custom-built R28 and completed two rather cautious warm-up laps of the technical 11 turn 3.2 km road course. Much to my surprise, given my recent experiences with my R28, everything seemed to be in order. So I gave myself the "green flag" to gradually increase the speed.
Strangely, the first thing I noticed about my R28 at speed was the sound, or the lack thereof in this instance. It was something I hadn't paid much attention to on the street, but with my helmet on out on the track, there was definitely a very distracting "silence". HPA had installed a slightly modified Euro-spec 4Motion Golf exhaust during my 4Motion conversion. However, a real "R" is known for its beautiful exhaust note that was an absolute must to emulate, and the raspy-whirring rearward sound of a 911's air-cooled flat six cylinder engine was going to be a tough one to replace. This sound quality issue would have to be addressed relatively soon.
The handling of my R28 at track speed took a little more time to get use to. Initially, I could feel that with the R32 KW Suspension V1 coil-over kit on the car using the OEM sway bars cornering was extremely flat and stable while exhibiting composed damping and very little harshness of ride. Also, the 4Motion grip was extremely apparent, even before the tires heated up, as there was nothing I could do to get the rear to step out. Having come from a track driving background of tail happy RWD cars like my 911, I found this to be both amazing, yet disconcerting at the same time. However, the understeer in the tight corners was a little too much for me. I would have to do some serious research on the VW Vortex to help dial in the handling more to my liking.
Next on my critical hit list were the brakes. My R28 came from HPA well equipped with vented 312mm rotors up front and vented 256mm rotors in the rear, basically, Audi TT 225 or Euro VW Golf 4Motion spec. The rotors were also slotted and stainless steel flex lines were used. This was an excellent set-up for the street with some odd track days thrown in every once in a while. However, being the "Track Junkie" that I am, I was a little disappointed in their total performance. At the limit I found the pedal feel to be rather spongy and difficult to modulate due to the inherent flexing of the front single piston calipers. Also, I was use to a bit more braking effectiveness, and I could feel fade setting in after 10 laps of hard charging. Things would have to be changed here as well
Enhancements:
The soft mellow note of my Euro-spec 4Motion Golf exhaust was great for a quiet drive around town, but it was eventually cast aside in favor of a Blue Flame R32 stainless steel catback exhaust system with resonator. For my custom R28 application, this new catback system required a welded on stainless steel extension to allow it to bolt perfectly to my unique Euro 4Motion Golf dual down pipe and cat set up. The new combination proved to have ample good quality sound at the track (befitting any real "R", yet slightly more refined) with reasonably civil noise levels on the street and highway without any cabin drone whatsoever. Also, the new catback system very noticeably improved low end torque.
After quite bit of experimentation, handling could be slightly improved by staggering the tire pressures for track days. Using 17in rims and tires on my R28 cold tire pressures were found to be best when set at 40 psi in front and 36 psi in the rear. This allowed for pressures to increase during a 25 minute track session to ~45 psi in front and ~41 psi in the rear, and resulted in slightly reduced understeer. After a further two or three additional days of track experience in my R28, as well as some "car-porn" reading (as my wife calls it) on the VW Vortex R32 forum, I was able to zero in on the parts and adjustments that would be necessary to further "dial-in" the AWD handling even more to my liking. I decided to lower the car a further 15mm to a total of 30mm from the stock R32 ride height and add a few trick suspension pieces, namely a stiff Neuspeed 22mm rear sway bar and a beautiful, but functional, pair of Custom Performance Products (CPP) stainless steel adjustable rear control arms. The height reduction lowered the center of gravity, the rear sway bar stiffened the rear end (further reducing understeer), and the rear adjustable control arms allowed the camber to set back within OEM specifications. Too much rear camber (caused by lowering the car) causes the car to "tram", that is, the car prefers to continue going in a straight line, making the car more difficult to turn. For the finishing touch, I had the car corner balanced and precision aligned at a local shop (Riegel Tuning/Maher Racing in Calgary) to properly take advantage of both the height adjustability of the coil over kit and the camber adjustability in the rear due to the new adjustable control arms. The resulting handling was now greatly improved, much more neutral, and easily induced into oversteer. Thus, allowing one to rotate the car if necessary during cornering with various types of driver input.