My shop is planning out a custom turbo for me and they said i could stick with the stock exhaust diameter( i'm going spugen ti single) if i so chose. They mentioned that since i hadn't planned on anything more than 290-300 to the wheels i should be fine. Comments on this.

Brandon

 

A free flowing exhaust if one of the fundamentals of creating power with FI, and more importantly, keeping detonation down.

The stock exhaust is pretty good for NA, but it just won't flow enough for you to produce the power you want with FI.

On a more positive note our cat is one of if not the most free flowing stock cats there is.

Random Technologies had to go to a 4" cat to flow enough more to make it worth while to produce one.

 

I would think atleast 3 inch.

 

Unlike a NA application you don't have to size the exhaust pipe to maintain velocity (and therefore torque) so there really is no maximum size.

In a turbo boost is made by the differential between the exhaust pressure ahead of the turbo and the pressure after the turbo. So the less pressure after the turbo the easier it is for boost to be made.

I don't know why the same thing works for a SC, I just know it does. Or at least that's what all the mags and books say.