Originally Posted by mrphotoman
typically the turbo will have a narrow powerband compared to the wide powerband of the supercharger. I have seen it countless times at the track, a wide powerband beats a narrow peaky powerband even if the peaky turbo powerband has a higher peak whp than the car wtih a wide powerband.
There are some cases where the turbo is matched well with the motor and the powerband is pretty good but a lot of the time you do not have that nice wide powerband that makes your car fast, not just roll racing
fast.
All, I can say to that comment is: "Go out and drive some more turbo cars" cause the ones that you have been playing with must have been really poorly set up. True that a flat broad torque curve will often beat a narrow peaky one at the track. But every turbo that I have owned or had any seat time in had a very broad torque curve. Porsche turbo had serious power from 3500 rpm to redline at 6500. My MR2 had serious power from 2500 rpm to redline at 7000. That is a useful powerband of 4500 rpm. It surely is not "Peaky". My Mazda turbo made serious power and full boost from 3k up to 7k. My Honda turbo makes power and full boost from 4k up to 9k rpm. It pulls as hard at 5k in 5th gear as it does at 9k in 3rd gear. The "only place" the supercharged engine has a real advantage is from off idle up to whatever point the turbo is making full boost. Usually that is a narrow range. From that point on, the turbo makes more torque and more hp for the same level of boost and stress on the engine. The supercharger will have a small advantage in an autocross type situation or in a very technical tight road course where the off boost to on power transitions are numerous but if the track has any place where the full output can be applied, then the turbo car will reel in the others fast.
Irish