I am curently in the process of configuring a new exhaust and I was wondering who runs a cat-less ekhaust and how much of a gain in power does it provide over running a high flow cat??? I am planning to run a 3" turbo back to the mufflers, but I would like to get some knowledgeable input first.
Thanks

 

I can't speak for the turbo side of things, but I run totally catfree here in Iowa on my NA, and it feels quite nice.

If your state doesn't require emissions testing, and you don't mind the rather interesting stench of uncatted rotary, run without cats. Otherwise use them.

-=Russ=-

 

I believe the number tends to be around 13% more horsepower - with a turbo the more oepn exhaust will do more.

I ran with no substrate in my cat after it clogged and it noticeably revved faster and accelled faster. I plan on building an exhchange pipe for racing so i can switch my cat on and off.

3" and catless should allow your car to breath a lot better - as a turbo you'll need to port your wastegate etc.

 

Yea you'll want to port your wastegate but the performance increase is awesome . .You wont regret going with a 3 inch exhaust. Or bigger

 

I am going to remove all emissions and pull the turbo within the next two weeks. I will be porting my wastegate and my exhaust mani runners. I am just waiting on all of my new gaskets to get in before I do all of this. I have a RB 80mm downpipe that I am going to work from. We do not have any emissions laws in Alabama!!!