I hear and read different opinions on this subject. Some people say 2.5" is ok and other say 3" is the way to go. Im finding a ton of mufflers designed for turbo'd cars have a 3" inlet too. So what gives? Is 2.5" or 3" the proper sizing to use?

 

depends on the car, but 2.5" will be plenty in almost every instance.. free flowing, mandrel bent 2.5" can support a ton of flow.

 

2.5" piping and 3" exhaust.

 

I forget the actual numbers, but an acute 180 degree mandrel bent 2.5" pipe can flow a hell of a lot of air.

Unless you're building a purpose drag car you'll never need more than 2.5" on an I4.

 

mine is 3" from the turbo and about halfway to muffler is 2.5"

 

I have a 3" DP, to a 3" pipe underneath, to a 3" HKS High Power Silent Specail Edition. I love it!!



Also really 2.5 Mandrel bent is fine, you wont notice a diffrence, you really only can tell the diffrence in pitch which i personally think is Fine, My car has a great growl now with the 3"...

 

I bolive the best for a piping for a turbo car is NONE!

 

^^^^ LOL So true,You should just cut a hole in the front bumper then just do a 3" dump tube out the front bumper... that would be sick!!!!!

 

That's what a bunch of people do here!

 

2.5" for boost piping and 3" for exhaust. Less backpressure is better so there really is no exhaust pipe too large in diameter.



I'm considering moving the alternator to the location of the a/c compressor and just running the downpipe out the front bumper :-P.