So it means bigger plenum. Bigger plenum means more torque in lower rpm area, and lower HP in higher rpm area... Just as I sad... IMHO waste of money and time, and degrading performanse of a car...
longer runners means less HP!!!!! Why? Because shorter runner would optimise inlet for higher rpm, and there is the gain... Longer runners would give you some torque in lower rpms, but you would lose HP and torque in high rpms... On NA engine, only possible gain in HP is to bring engine on higher rp...
just wanted to share with you guys my dyno results from my long waited mapping session. did a few dyno runs, we started with 140whp and 132lbft. but the power band was cheesy, had timing holes, running very rich from 3500 to the limiter (AFR around 11.1~10.4) in the end gained over 8 whp/10 lbft on...