Test pipe or high flow cat, which one will work best with on my 01 s2k with a Borla exhaust?

 

What do you mean by works best?
Most power? Best sound? best to pass emissions?
All depends on what you want to do?

 

If you live in Cali...just forget it...

 

in general though, i'd choose a HFC over a test pipe because tests have shown that they perform just about the same, while the HFC obviously is better for the environment and doesn't stink as much either.

 

HFC sounds better imo with aftermarket exhaust

 

Thanks.I've always replaced my cats with straight pipes on all previous cars and always passed emissions here in Wa. Its off my TDI, was off my S4, S60R, 911, older V8 Audi ans 900 Turbo. Was always told it was better for the engine. Never heard of HF cats before the s2k. Is the straight pipe that much louder?

 

How much quieter is the HFC compared to a testpipe?

I think I might get one since it doesn't smell as bad as a testpipe, from what you guys are saying.

 

I've been to a country where there are no emission controls. I can't run a test pipe.

 

Performance is going to be pretty much equal between a good HFC and a test pipe. If you don't have to do emissions, you can save a little money getting the test pipe.

I have a berk 70mm on an otherwise stock CR exhaust and I didn't notice any real difference in sound from the factory cat. I'd imagine you would notice a little increase in volume adding the HFC to a less restrictive exhaust.

 

How badly does a test pipe smell?