I am gonna have my exhaust system installed today or tomorrow. The only thing is the shop that is going to bend the pipes for the enxhaust for me can only do it 2.25" in the back, near the muffler. All my header/cat **** is 2.5" Is this going to be a problem?

 

Actually 2 1/4 inch pipe will definetely help you. It will work smoothly with 2.5 inch header and CAT. Don't put 2.5 inch exhaust because it will "dramatically" decrease your car's low end power (from my personal experience).

 

2,5 exhaust increases your TOP END POWER
so if you have a stick shift it will be BETTER
since when you shift,... you end up in the 4000RPM range

and auto puts you in a lower RPM range

if you have a stick,... go somewhere else

2.5 ALL AROUND!!! FOR 5 speed

why would you want lower end power if your only going to use it on 1st gear rolleyes.gif

but if you have an auto,... go with a 2.25,.. you should also switch the high flow cat and try to get a 2.25

dont corrupt your exhaust,... it will add restriction and screw you over on the power side

 

As exahust gases flow away from the engine, they cool down. It is okay to shrink the diameter of the pipe from 2.5 to 2.25", as long as it is done as far away from the Cat converter as possible.

The Cat Converter creates/maintains/stores a large degree of heat, so you will still want a 2.5" exit pipe out of the cat. However, just before the rear axles, it would be okay to go down to a 2.25" pipe. It will allow the cooled/contracted exhaust gasses to maintain their momentum/velocity.