I have an hks exhaust, and wanted a louder exhaust tone. After asking on this forum, I decided to get high flow cats, basically because its legal and not obnoxious like test pipes. But I was wondering if these are the only options instead of the stock catalytic converters? Since the pipe size of the stock cats are so small, are there any cats out there that are bigger? Wouldn't that mean a louder exhaust note?

 

no one?

 

HFC are no more legal than test pipes... you are more likely to pass the sniffer test during smog inspection though... but upon visual you will fail (and possibly be fined)... I have Crawford because they look stock - but when its time to smog I'll probably install OEM cats just to be safe.

I know that doesn’t directly answer your question but I wanted to be sure you knew HFC are not "legal".

 

hmm really? I thought some were illegal and some were CARB legal.

 

They are legal, but technically legal if you have over 40k (i think, may be more or less) miles on your car.

 

????

 

OP lives in CA – I’m only addressing CA (I don’t know about other states)… CA is very stringent on emissions standards. I can tell you first hand if you have altered your cats in any way you will have difficulty… I’m not going to debate people that “think” they know the law or what smog techs will do – I’m telling you from experience.

If someone (in CA) thinks otherwise, feel free to get your HFC inspected by a “normal” (not “special”) smog test facility and let us know if you pass visual – if your cats look stock you might pass – if they are clearly aftermarket (FI, Berk, etc) don’t be surprised when you don’t pass.

 

Keep your stock cats.