Originally posted by senseiturtle
Forced induction works all too well, because it increases the amount of torque available at high rpms. Engines have an "optimum operating range", determined by the size of the cams and the flow characteristics of the head.
Since your car acclerates at the level of torque, and racing involves high RPMS, you want lots of it at high rpms, and boost is an easier way of doing this than swapping engines.
You are correct about swapping, but there's a size limit to what a car nowadays can accept. I'd love to stick the twin turbo audi V8 into my jetta, but we can't win them all. Boosting what you've got, then becomes the answer.
Ya those VW engine compartments are pretty tight aren't they? Other than better heads or a different camshaft profile, a turbo would be your ticket to more power if space is at a premium.
Racing does involve higher than normal RPM you're right, BUT you can't run in the redline for the whole track IE on a hairpin turn. The real bennefits of turbo will come on long straights as opposed to areas of the track where you are trying to "power" your way out of tight corner exits. But for normal street driving, low end torque is where to put your money to make the car really work for you.