Was wondering if anyone has dynoed their cars with high-flow cats but stock exhaust? Any gains from that by itself, or do you need aftermarket exhaust along with the cats to see any increase? Also, how different or louder are HFCs compared to the stock cats if you leave your exhaust stock?

 

it depends on which hfc you get but either way the hfc are gonna flow much better than stock and give you some hp, not much obviously. The stock y-pipe is also very restrictive. All hfc really will do is make your exhaust sound a bit louder, probably barely noticeable. I doubt anyone is gonna waste money on dynoing a cat swap, or at least I wouldnt, with the stock exhaust.

 

What's a good brand for a cat?

 

berk technologies, I love mine.
http://www.berktechnology.com/

 

Thanks.

 

I have topspeed testpipes on stock exhaust.


you check it out here:

http://youtube.com/watch?v=_DzpSqXJDiI