Originally Posted by
custom240sx
Basically what he is saying is that intake manifolds are tuned to provide significant gains in certain areas while sacrificing loses in other areas. The restrict flow to provide gains to a specific area. Just as an intake pipe can be tuned for diameter and length to provide gains in specific areas. If you go too big on these items you push your "power band" too high for the motor to reach therefor actually losing power. The TB also plays the same role...it is a balance that you must have in order to actually gain power from these bolt ons.
If bigger was always better, why doesn't everyone have a 78mm TB with an air filter directly on the TB and a Victor X manifold?
I agree the intake manifold design will change your power curve. Runner length ,cross section , and taper as well as plentim size and shape. Ive personally not seen power changes with due to T/b being to big. The inlet size will not change the power curve. The victor X has very short runners and a large plentum. That is not Ideal for stockish setups.