Well there are 4150 style throttle bodies out there that will far outflow a 90 mm throttle body thats for sure. However in a boosted application the difference between an adequately sized throttle body and a max effort larger one will show little on a dyno. The theory being that boost is a result of some sort of restriction. Take for example a D1 procharger(I choose a procharger so we know the same amount of air is being moved) : with the same size pulley on it it might make 10 lbs of boost with the 90 mm throttle body that flows 1000cfm and 8 lbs of boost with the 4150 throttle body that flows 1250cfm. However, both with make darn near the exact number on the dyno. The reason being the same amount of air is making it into the cylinders in the end. Now take into consideration the 90mm will have its limits to where its a restriction once you go above and beyond 1000 rwhp and I am also assuming both situations have an intake that can adequately take advantage of the flow of each respective throttle body. Another thing to consider is once you go to a 4150 throttle body you are pretty much stuck with a speed density tune which many consider to be the best for boost anyways but thats another debate in itself.
|