The ring/pinion in my Z06 are going out so I didn’t want to chance racing it this weekend, yet I still wanted to run for points. Dan Bratten was nice enough to offer up a co-drive in his '06 C6 to me. I took him up on his offer, and suggested we use my race wheels/tires for the weekend.
The car:
It’s a '06, base level with the ONLY options on the car being the Six Speed Automatic tranny and polished wheels. No Z51, no Nav, no blah blah. The car is black on black.
The only mods on the car are '06 Z06 shocks and sway bars.
First Impressions:
A lot of the talk when the C6 hit was about the much improved interior. I’ll admit: the interior is nice. In fact, much nicer than my '02 Z06. I’ve seen the C6 interior in some of the other color offerings and it just didn’t work for me. But the black (Ebony is the “official” name I believe) worked very well with the various bright-bits and styling elements Chevy put into the C6 interior. The seats are very comfortable, but still not supportive enough for aggressive driving. I’d say they’re slightly better than the seats in my Z06. As for the exterior Black really works on the C6 and even on the stock wheels it’s a great looking car. I’m learning to love the C6 slowly.
The A6 w/ “paddle” shifting should really help sell the C6 to people looking for more of a comfy/fast/flashy cruiser than a balls-out race car. I can see the A6 helping to push the C6 into the BMW 6-Series and Mercedes coupe market a bit. However, when you really look at the ratios the performance advantage isn’t what I hoped for over the A4. The A6 uses an insanely deep ~4:1 1st gear ratio but a very mild 2.56 rear-end. When you run all the #s the overall drive ratio in the first 3 gears of the A6 are actually deeper than those in the A4 w/ the 3.15s (optional perf. ratio) so it will be at least some benefit for the straight line junkies in the stock configuration. The insane-o 4:1 1st gear would make a great combo w/ some 3.42s or something in the back, a high-stall converter, and ETStreets for the 1/4 folks. I’m sure GM chose to go w/ such a huge spread on the A6 so they could combine slightly improved performance with better fuel mileage. I would have rather seen them go w/ a reasonable rear-end ratio like 3.15 or 3.42, a more standard 1st gear (high 2.xx low 3.xx to 1) and very tight gear spacing on the rest of the gears with 5th being a 1:1 and 6th being the only OD. But alas, that would have really only benefited in AutoX or Road Racing. In most cases customers of the A6 probably aren’t as concerned with those venues. By the same token I’ve always wished the M6 was a single OD w/ a 1:1 5th and tight gear spacing. Anyway, I digress…
Racing:
My 17x11 wheels (Grand Sport offset) with Kuhmo V710 (315/35-17 front and 335/35-17 rear) tires fit right on. As mentioned the car is a base model and has what appears to be the same braking system as a C5. The 17s had no issue clearing the brakes. And the big 335s actually clear better on this car than they do mine. We didn’t need to run a spacer at all with this setup (for reference I use a thin spacer in back w/ the 335s). They did stick out around .5" just like they do on mine. The rims would contact the tie-rod end in the front at full-lock though. I get rub on my car at full lock also but as far as I can tell its tire to brake-duct rub not rim to tie-rod. Not a major problem, we just had to be mindful to not go full-lock (not an issue for racing, only in the “pits”).
Saturday’s course was a nice mix of tight, technical sections and faster sweeping turns. There were about 3 decreasing radius sweepers which are always fun.
The car got out of the hole pretty good. I could brake-torque it up as high as the converter would allow and it’d leave with no spin from the 335s (and that is with the electric nannies turned full off… but the PCM is obviously still limiting wheel-spin off the line… gh3y). 1st gear acceleration was considerable. Through the first section of the course (what could be roughly described as a slalom) the car was composed and reacted well at turn-in but the quick transitions would unsettle the rear some. It was easy enough to catch it though, and the active rear-end could be used to work the car though the gates. Through the sweepers, particularly the decreasing radius ones, the rear-end wanted to lead the way. Lift-throttle over-steer was huge and could really sneak up on you. Getting into the power coming off the turns also threatened instant over-steer. Overall power was good if bit underwhelming (remember, I’m spoiled w/ my car), especially when I’d be stuck bogged down a bit in 2nd. With more experience with the car I’d learn when I need to downshift to 1st heading into a turn to have the necessary power coming off the turn. More familiarization w/ the A6’s ratios and shifting would really be necessary to extract the best times from the car.
Saturday night we decided to do something about the very loose condition we’d been fighting all day. As mentioned the car had been upgraded to C6 Z06 sway bars front and rear. The large back bar was surely one of the culprits. C5 AutoXers are known to like no rear bar at all. From my experience with this C6, it’d seem the same applies. However, with the stock base model springs and the miles of sticky tires body roll was already considerable and Dan really didn’t want to induce more. So instead of removing the rear sway bar we turned to some rear Toe-In. We cranked in darn near ¼” of rear Toe-In which is very aggressive. But since we wouldn’t be reducing the rear sway bar (we didn’t want to make 2 changes at once) we decided to go on the aggressive side of things. We marked the toe-links and made sure to count “flats” as we made the adjustment so that our changes would easily be reversible.
Sunday after the car’s first lap we knew we had made a large improvement. Dan drove the first lap and I rode shotgun. I could tell he wasn’t fighting the tail of the car the whole way around like we were on Saturday. After the lap I asked him how the change felt and he said “I hadn’t even thought about it.” To me that was a good sign, there was no way we weren’t thinking about the tail of the car on Saturday. Hell it was just about all we could think about on Saturday. I took the next lap and the improvement was night and day. I could brake later and harder, executing my turn-in while still under braking. That would have brought the tail around on Sat. for sure. This really allowed me to drive the car harder since I could hold out WOT a bit longer, brake later, then turn in with front tires fully loaded under braking. I could also roll into the throttle through the turns and get WOT much sooner.
Overall for a close to stock car it was very capable. Once we got the rear Toe-In taken car of it was composed and predictable. The A6 worked “okay” at best, and as mentioned I could have used the paddle shifting to my advantage better with some more seat time. But the shifts were pretty slow and I’m just not happy with the ratios. The handling was nearly on par with my Z06 despite the softer base model springs. The C6 is a nice evolution of the C5. Nothing is new or revolutionary (well accept maybe the A6 itself), but many refinements are present. Now if only somebody would pass me the fob to their C6 Z06.