Hey guys. Me again. I was wandering if I needed a downpipe in order to install a bigger turbo, the 16G. I only have a catback exhaust system (3" Greddy Evo2) Do I need to have a turbo back exhaust system?

 

well you dont absolutly NEED it....but you def. should buy one because that bigger turbo is gonna take longer to spool up and a downpipe will cut that time down by alot. I highly recommend you buy one if your upgrading your turbo.

 

Thanks man. The only thing running through my head is the stupid emissions. But thanks for your help.

 

bigger diameter piping wont fail you, not having a cayt will. Dont get an apexi down pipe, it elminates the cayt.

 

Yeah, I am having the hardest time finding a downpipe that DOES NOT replace the cat. Does anyone know any that dont?

 

Road Race Engineering makes one... http://www.roadraceengineering.com/eclexhaust.htm

 

hmmmmmmmmmmmmmm. Is any back pressure necessary on a turbo engine? Obviously you cant go too big on an n/a engine, but yeah...

 

Is that the only downpipe you guys know that does not replace the cat? Do you guys know anymore?

 

if your car is runninng in proper condition it should pass without a cat because my 93 gsx did and they didnt look under my car with a mirror like they are suppposed to be.

 

Are you sure it would pass? I think the cat is one of the most important things to have in your car. It burns something to keep the air clean, which is needed in order to pass emissions. This was made mandatory in the US years ago. I just dont want to take a chance. And I definitely dont want to FAIL. (I wrote a research paper on the cat) Hahaha. If you are 100 percent sure about this, I will probably do it.