Last month we completed the installation of the ProCharger D-1SC supercharger system on our '05 C6 with a few custom touches from Torq Speedlab to help it crank out 565-rwhp on 11psi of boost. While the install was thorough and complete, we weren't quite ready to head out on track. First we would need to fix the poorly designed factory PCV system, no shock to any LS enthusiast, which seems to have been exacerbated by the vast increase in cylinder pressure. This was an easy fix with a call to UPR Products who had a billet catch can ready to ship that would help remove any oil and contaminants from the air stream, causing misfires and detonation.
Now that we had ensured the longevity of our blown LS2, it was time to focus our attention to the drivetrain. To hit our goal of keeping pace with a stock ZR1, it seemed the most cost effective means would be to pick up a set of 17x9.5-inch wheels and drag radials. The smaller diameter not only cuts down on weight, but it allows for a meaty sidewall. Ideally we'd have a set of 15-inch race wheels with slicks, but C6 brakes don't allow for that kind of clearance and the drag radial is more street friendly for those of us who drive to and from the track. Thankfully Corvette Central Performance had a set of C5 Z06 wheels that fit beautifully, so we called up Nitto for a set of NT05R 275/40/17 drag radials to seal the deal. We've had great luck with these sticky little devils before, and I was excited to test them out in a 25.79-inch diameter (11.02-in. width).
Of course, just bolting on a set of sticky tires and letting it rip on virtually any late model GM car, especially one with IRS and 200 more horsepower than stock, is usually not a good idea. Thankfully we had previously traded the 2005 model's glassjaw of a rear end for a Z06 unit stuffed with an OS Giken diff and hardened output shafts, courtesy of RPM Transmissions. We even added a RAM 9.5-inch twin-disc clutch. Unfortunately, though, our new power output would require RAM's larger 10.5-inch clutch, and aftermarket axles. RPM recommended either stock C5 axles or something from the Driveshaft Shop. Since we have Frank Rehak on speed dial, we had the Driveshaft Shop's Level 5 axles in the mailroom by the time we put the phone down. And while we were in there, it also made sense to replace the rubber factory driveshaft couplers before turning it into confetti like so many we've seen decorating shop floors.
Now that the keyboard stroking and phone calls had been finished, it was time to do the real work. We headed over to AntiVenom in Seffner, Florida, who has handled all of the drivetrain and chassis work on the C6 thus far, and in no time we were ready to head to Bradenton Motorsports Park for some fresh timeslips. Achieving a time I could be proud of while finessing the 6-speed and not causing any carnage would be a task. But with all the hard work that has gone in thus far, I was determined to make good on those efforts.
23. With the new wheel/tire combo bolted up, we headed to Bradenton Motorsports Park. It took quite a few passes to get a handle on the new combo, but the sounds the ProCharged C6 was making drew a crowd. The tune appeared to be spot-on, and the car ran near flawlessly. While I had initially thought the taller gears in the Z51 trans would be a good complement to the centrifugal blower, it made the car very difficult to launch. Best sixty-foot was a 1.61, however, on average the C6 ran a 1.75 to 1.80 short time. A headwind seemed to hurt the mph and e.t., but I was pretty happy with the 11.33 at 123 and don’t believe a stock ZR1 would have been able to outrun me that day. Success!