Performance to sound relation....

 

Have you guys done any flowbench testing with the 150-200 cell cats v/s the 300-400 cell cats?

 

Nope..but pretty obviouse that you'll have more flow with bigger holes in the same or larger diameter.

The 300 cell v. the 400 cell cats show an average of 3-5HP better to the 300 cell cats. Also, the 400's FI has are ceramic, where the 300's are metalic.

Having 1/2 the cells (150-200), means that much more flow.

Rick

 

Will two 2.5" cats be enough to pass smog/emissions on an NA?

 

I think Tony ought to think about 3" 200 cell metallic cats for the FI crowd.

I'll see how my 2.5" 300 cell metal cats do on the dyno w/ TT in a couple weeks here...

 

any updates?

 

i'm still a couple weeks out from testing the FI 2.5" metallic cats near the 500 whp level. Tranny work was delayed, but that's all done now... If those sap power, I'll ask Tony for some 3.5" 200 cell cats...

 

I got discouraged about the whole high flow cat thing after talking with Tony @ fast intentions. He said he's installed 5" metal cats on the porsche 997 turbo and was dissapionted in the flow. He also said the porsche guys were paying huge money for them out of Germany.

 

You went with test pipes then? I'd really like to avoid test pipes if I can. I am also considering electronic cut outs that only open above say 4000 rpm (so I can keep it quiet if I want to). Problem is those are prone to failure, are a tight squeeze in an already cramped area, and cost a good bit ($500) to do it right.

Maybe I'll just have to settle for whatever I get horsepower wise...

 

Yeah, I went with test pipes and I really have'nt wanted to go back to cats. The very first pull with test pipe was all I needed to sell me. It has a lot more grunt now.

I figured if 5" cats dont flow I was'nt gonna be happy with 3.5"

The smell doesnt seem as bad now and I'm not throwing a CEL. Go figure.

 

The 997 would use a single 5" cat, yes? That would be roughly equivalent to dual 3.5" cats. I always wondered about doing something with the X-pipe instead where you have more volume to work with...

 

There is a guy who installed two 100 cell 100mm diameter cats on his E55amg, and pushing 535 WHP...

 

Those cost like $2k each I believe