what inch exhaust piping
 

what inch exhaust piping should i use on a turbo fc

The consensus is 3" is optimal for performance. Keep in mind you will probably experience boost creep with such an exhaust. In fact if it's a S4 then you will probably need to take measures to combat it. eg. port wastegate.

2.5" -> 300hp
3" -> 500hp
3.5" -> 700hp
4" -> 1000hp

2 x 2.5" = ~4"

These are the approximate pipe diameter versus HP numbers I use as a rule of thumb.
All numbers are hp at the wheels.


-Ted

now the question "what is too big" needs to be answered.

6'' is too big i saw a guy with a tip that you could stick your hand in and have room to move arround it was crazy. he was a fucking idiot also. the rest of the exaust was fastory (on a civic HAHA)

On a turbo, there is no such thing as too big.
It's a matter of what you can find under the car and how much you can afford to pay.
Exhaust pipes over 3" are not very easy to find or cheap.


-Ted