hey guys, i put a very free flowing exhaust on my 99 GS about 3 months ago including OBX Racing Headers, OBX 3" downpipe, OBX High Flow Cat, Hahn Racecraft (Thermal Research n Delvlop) 3" cat-back exhaust... now, i put my AEM CAI on about a week before that and could definatley tell a difference in the power of the car, when i put the exhuast i was expecting to feel the same kind of gain but i didn't, i didn't feel ANY gain infact it almost seemed a bit smaller... could this be to free flowing for a stock GS w/ only a CAI??? it also has a bit of a rough idle, could that be cause for it also?

 

3" is too big for a n/a

 

Yeah 3" is way to big, n/a motors need backpressure. I dont even have that and I have a turbo.

 

3 inch is way to big.

 

3in is WAY too big. 2 1/4 would be a nice size for you.

 

2.5 tops and on top of that you should know you really wont feel much of a gain on a N\A car at all anyway

 

Yeah I agreee, even 2 1/2" after the cat would be fine.

 

well hot damn lol see when i put my exhaust on i thougth i was the man b/c i thought that the more free flowing the better..... sooooo since i have all this extra width, how do i make it smaller?? sell my current exhaust and get a new one? or can i just get a new downpipe and cat and be ok??

 

I thought you got a gsx?

Any way n/a motors need back pressure to make hp, and a free flowing exaust helps but too big and bam no more bottom end power. The only way to resolve the issue would be to get a new cayt back.

 

that sucks... oh well. i'll just take this exhaust off and put it on my GSX. and yes i do have a GSX however its sitting in my garage w/ no engine in it right now. i'm building a 4g63 from the bottom up prettymuch as well as i know how so until i do i'm going to be driving the GS around, it's lower insurance and better on gas. but thanks for the info guys.