At blackhawk, there is a sequence of turns (which is actually two linked turns, a right hander immediately followed by a left, turns 3D and 4--not really a chicane, but to full-fledged turns. This is almost immediately followed by turn five, another lefty). The "best" gear to take turn three would be second, if there wasn't anything to worry about beyond that. But if I take it in second, then I have a dilemma, because I'd have to shift to third while turning on turn four. So the fastest, smoothest way to get through that complex is to stay in 3rd before turn three (that's the gear I come into three in, don't even need to shift), and carry that gear all the way through turn 5. And this is where I pick up the most time on everyone. Problem is, there is a short straight between 5 and 6, and if I shift into fourth, almost immediately afterward, I have to brake and downshift back into third. It's faster to hug the rev limiter (but not hit it) than upshift, and immediately hit the brake zone, not to mention trying to that many things at once and rushing it. Maybe it would be different in the turbo, and maybe Schumacher or someone could eek out a little bit more with perfect shifting, but I'm substantially quicker this way, and it makes keeping the line and momentum very easy through those turns. My car is a 2006, with the shorter gearing, and 225/45/15's, which shortens the gearing even more (my third gear is almost like second gear in a 2002). An instructor with a 2003 MCS and 17 inch tires hits this totally different because of the difference in gearing; he has to get through the complex in second, then shift into third between 5 and 6. It's amazing how gearing can be so much different from one car to the next. That being said, he much prefers the gearing in my car.... Anyway, bottom line is like Dr. O said, sometimes it's not worth it to upshift, at least not in the supercharged car.
In Autocross for years and years I would regularly ride the limiter in everything from my S2000 to the 911 GT3 I ran from 05-07. I never thought twice about it. Last december I was at a dyno day talking with a tuner that happened to be there. (I think he was a ford/evo guy, he was working with a new SHO). And he had an interesting view point on it. His View was that when you hit the limiter it's a fuel cut in most cars. What if your injectors leak a slight bit or there is some fuel still in the manifold that makes it's way down into the cylinder (especially on a boosted car). That fuel is going to be forced into the engine and your going to have a VERY lean combustion while on the rev limiter. Not sure how accurate his opinion is but it's made me think twice about riding the limiter now.
I've thought about that too... but I haven't been hearing about blown motors cause of lean on the limiter. Also, I don't know but it's possible to cut both fuel and injection on a per cylinder basis. I honestly don't know what the cars do. If I were programming them, I'd do both. with carb'ed cars you have to drop spark and get those nice flames out the exhaust. But with computer controlled FI, you can cut both. Anyone data log the car to see what it actually does? Matt