what does "carb certified" mean? Are carb certified cats less restrictive than the no carb certified ones?

 

It's to do with Calafornia ARB emissions requirements/standards.

 

so the carb certified cats are more restrictive, right?

thanks

 

not neccessarily (sp?) It just means they have been approved and certified.

If you're in CA then it's probably a must, if not then it's up to you how important it is.

What Cats are you looking at?

Random Technology make some very good cats. you need to look for flow rate.

2.2cfm per 1hp

Their 8100 series flow pretty decent for a bolt on Ls1 with little or no real flow loss. The 9000 series flow better but are physically bigger.

The best (and slightly more expensive, but not by much) are the Metal Matrix 7000 series units. I believe LG use these for their catted headers/X-pipe for the Corvette. They flow around 580cfm so should be good upto 500bhp or so (1 cat per bank, so only need to handle half the flow rate). And beyond 500bhp they will only be slightly restricted unless you're talking insane BHP.

 

To answer your question, my guess is the CARB ones are more restrictive than some of the other cats. Most of the good high flowing ones will set off an ses light because they flow so much. If the CARB ones flowed high enough to set off an ses light, they wouldn't get CARB approved. So no, I don't think the CARB ones flow as well as some of the other high flowing cats.

 

ok thanks both

 

I noticed the texas speed catted Y pipe is about $100 less than a pacesetter y pipe with random tech cats, any ideas what flow difference do they have?