Originally Posted by
KnightDrifter
Longer runners/smaller dia.= low end torque
shorter runners/larger dia.= high end power
it all comes down to velocity/or air flow/speed. Thats why honda runners are shorter, and bigger for top end power, and the ka has smaller longer runners for low end torque. hope that helps
so thats why when you do ITBs, the runners are so much shorter, you don't really gain anything down low. its all high end gains... more or less...