Lt. Dan said:
Yup, all the 3" will get you over the 2.5" is noise.
Let open this up for some friendly debate. Im not 100% convinced of this
Everyone keeps saying, 250whp this 250whp that.... "If you dont plan on going over 250whp, then 2.5in is enough" I am assuming that everyon is getting this from the article/book cork bell wrote....
The principles for a turbo charged car is the same, no matter what car you are reffering to. The less backpressure, the better.
The reason I say go with a 3" exhaust is because mods compliment each other.... A fmic/smic + 3" exhaust will yield higher numbers than with a 2.5" exhaust. Almost every mod in combination with a 3" will yield higher numbers than with a 2.5" exhaust.
For our car, I garauntee you that a 3" ghl turbo back exhaust (on a bone stock car) will produce better numbers than a corksport downpipe/ with 2.5" piping back. A 3" setup may only produce 1-5whp more. Although that amount is so little, I think it is false to say that you will see no gains and only create more noise...
(Mind you, if you plan on keeping your car bone stock, then a 2.5" turboback setup may be all you need). But for the people who do mod their cars, I think a 3" exhaust would be a better route. The more mods you do, the closer your car moves to that "250whp" number. The closer you get to it, the more gains you will see in a 3" setup over a 2.5" setup.
"250whp" is just too broad for me. Its not a CFM rating or measure of exhaust gas, its just a HP number. There are too many variables (displacement, # of cylinders, turbo size & amount of boost, intake, smic/fmic and their piping length/diameter, transmition, gear ratio, etc. etc.) that can
influence the amount of power that actually reaches the road. Its just too universal to apply to every car on the face of the planet.
