jeff28

Is a 3inch exhaust a good size or too much for the amount of exhaust that the new turbo will flow. Estimated 275-300hp turbo upgrade. Also, is a 3inch exhaust going to be a lot louder than say a 2.5 inch system. I have someone custom building the exhaust, and he is willing to change th resonator or muffler if the initial set-up is too loud.

SwifTT

it will be a little louder, but not by much. Flow will be much better as compared to a 2.5 inch system.

CMH

I am just waiting for a new MAF for the PES kit and my new exhaust. I will be posting pics and a review of how much they helped.

xr4tic

that's a huge difference, and should help considerably to decrease lag. The most important part is the downpipe and cat area, they should be 3" at the very least.
It will be slightly louder, but if it's too loud, you can always change the resonator or muffler, and it won't have that big of an impact.

Kawika

I heard that you lose a bit of torque when going from a 2.5 to a 3 inch on our cars. Always wondered about it because I am in that same dilemma of choosing the size.

dave

xr4tic

plus the camshaft valve overlap is less on a turbo motor, also making it less susceptable to torque loss.
And the exhaust manifold isn't exactly what I would call "high-flowing" either

CMH

of tq. This came from a race shop that races a few audi's. He tried to use a dump pipe but it lost too much tq.

xr4tic

Throw on a high flow cat and a full exhaust, and you'll still have plenty of backpressure