I'm going to make a similar video soon of the Spintech Prostreets w/BBK catted x. I just have to wait to get them and have them welded in sometime next week. I'll post the video here.
Wow, I just ordered the FM 50 Series because they sound so good, now after seeing those flow numbers I'm having second thoughts about actually putting them on.
i made 548rwhp with dual 2.5" 2 chamber flowmasters and my s trim. when i installed my turbo kit the flowmasters were a restriction and dynomax bullets picked it back up.
if you run a turbo you have blended exhaust and the flow numbers above are a lot more relavent. but if you are like most people and run pulsed exhuast they dont hurt it that much.
we recently tuned my buddies car and made 615rwhp with dual 2.5" 2 chamber flowmasters through a 4r70w. if you are only making 400rwhp, i wouldnt worry about it.
In general this is all great food for thought, especially seeing those
cfm flow ratings. The only way to find out the truth, and to prove
that there is strength in numbers, is.......
buy an F1 procharger, put it on a 298" livernois longblock and find out for yourself. considering we are running 1 5/8" bbk shorties on it probably not much of a difference. when we put a real set of headers on it we will worry about the rest of the exhaust. point is, if the ****tiest headers on your constant flow at 28" chart will support that kind of power and et, most people will be fine with them.
especially when you consider the fact that on a running engine, with the exception of a turbo car, you have a pulsed exhaust not constant flow. so flow at 28" is even less relevant on mufflers than it is on heads.