Im in the slow process of building a turbo kit for the 8.1L... It looks like im going to have to use a Y pipe from the dual exhaust into a single pipe to feed the turbo.

My question is this. I currently have dual 3" exhaust, off the headers.. when i Y those should i run a single 3" pipe to the flange to feed the turbo or a 4" pipe. Im assuming the velocity of 2 3 inch pips into a single would provice thicker exhaust gas, but im wondering if that will flow enought. Its getting fed into a T4 flange.

 

t4 flange is very close to 2.5" pipe.
4" would be a big step down.
The flange/turbo is the choke point. 3" will be fine.

 

I say 3 inch,

 

sounds good...

Guess ill see how much room is left before i plan on the dp and cat back...


Right now im thinking ill keep my dual 3" cat back and muffler.. just run the dp into a Y and let it go..