the stock pipes that goes from the muffler to the cat is 2.5" is that large enough if you're not going to be upgrading your turbos? pruven performance (on their website) say it's sufficient if you don't upgrade your stock turbo? what are your thoughts on this? my plan is to install a free flowing axel-back, keep the 2.5" stock pipes and cat, and install a 3" downpipe? is that a good idea? i'm planning to do this TODAY so i need some sound advice as soon as possible. help and thanks!

 

no, the bends are crush bent and the diameter is smaller then 2.5 inch, if your going to max out ur stock turbo you will need to upgrade the exhaust for max performance. You can however get away with just changing the muffler if your doing light mods. DP is another must.

 

1QWKEVO,
i looked at the pipes today. i only see the pipes really being "crush" with the downpipe which i'm replacing to 3"
this will be sufficient with my other mods? i'll be running
19 psi with 92-93 octane.
thanks,
AD

 

if your running 19psi to red i'd run atleast 94 octane. Throw ur DP on and run the stock exhaust, you will see gains by replacing the stock exhaust. However the gains maybe only 10hp or something. Soolup time will be quicker with a free flowing exhaust. I've been told that the muffler is the major restriction in the evo exhaust system, so if you want order an axle back exhaust from www.pruvenperformance.com

 

What's the stock DP size? Is it being 'crushed' rather than mandrel bent as well? Lastly, how much does a UR DP 2.5 change turbo boost and effectiveness?