Boosted Performance V 2.0 turbo list

Originally Posted by jwick

I'll start with I'm no expert but a couple things to note. First off, of course you are going to get some gains by adding exit diameter cuz you are decreasing the friction loses. The 3" and 3.5" in the article you linked are not like for like comparisons. They don't list what type of muffler was original on it with the 3". Also you can see that the newly fabricated 3.5" is more of a straight shot with less bends in it. More bends equals more friction. Although they don't address it, I'd bet they lost torque going to the larger exhaust.

I wouldn't get carried away with the fact that you 'only' made 509whp. Your numbers aren't much different than any of the other cars running a BP kit. For ex: jlo made 52Xish whp at 11.5.psi, that's about spot on where you are for a 11psi max and he's running a FI exhaust.

And then you thrown in all dynos are different and all tuners tune differently with different goals.