Quote:
Originally Posted by BlacknBoostn
Exactly what I was thinking myself... i'm on stock boost, stock turbo, stock stock stock. When i go with a ported turbo or s3 turbo i'll upgrade to 3in  only way it'd help now is for mileage haha... |
I sure as heck don't understand all the combustion theory and engine dynamics, but it does seem one of the most commonly overdone mods for I4s is an overly large exhaust. As I understand it, the problem is excessively reducing cylinder back pressure, thus torque and finally power.