1999 GT

whats up guys....is mac's 3" catback too big for gt's. will i be losing power? also the 3" prochamber is needed in order for it to bolt up correctly right?

StriderTacticaL

I never knew they made 3" catbacks. Are you sure whatever you are reading off is not refering to the exhaust tips? I think Mac catbacks come in 2 exhaust tip sizes, 3" and 3.5"

Either way, I heard that anything over 2.5" causes backpressure which is no good

1999 GT

http://www.latemodelrestoration.com/...0%201&comp=LRS

there ya go..its a 3"catback from mac

StriderTacticaL

hmm interesting. Either way like I said I've heard from many people not to go larger than 2.5"

oxfordgt

3" is overkill and like stated above it will cause backpressure. Unless you are well over 600rwhp there is no need to go bigger then 2.5".

Let me put it this way I am building my car to be over 800rwhp and have no plans to upgrade my exhaust.

califas_1987

you mean it DE-creasses back preassure right? More flow less preassure.

StriderTacticaL

It decreases pressure going out, INCREASES back pressure.

oxfordgt

No bigger pipe = gasses cooled too fast = less velocity = reduced flow = back pressure

crazyhorse

the mac 2 1/2 " prochamber /hpipe / x pipe will bolt up just fine to a mac 3 " cat back for a fox body , so i think it would bolt up just fine on your car too. good luck.

1999 GT

so would the 3" catback hurt the motor or cause problems?