I hear high flow cats do nothing, i talked to a guy who has been installing mufflers for over 40 years and he sais that they call them high flow cause they are bigger, meaning if u fill it with water it will hold more water. not actually give u any more flow? so what do u say?

 

the point of an exhaust is to remove gases out of the cylinder and do it at high rate. when you have a larger exhaust, you can remove the exhaust gases quicker, thus increasing performance. this is the whole poing behind an aftermarket cat- you increase the flow that comes through it. more flow is better to an extent. a high flow cat used with the stock exhaust system will not be that beneficial, i think thats what he probably was talking about. but if you install a high flow cat with a less restrictive exhaust system (something that flows better than the stock one), there will be a considerable difference. check this article out, it should help you.

 

dFreezy, you are all up on everything, seriously. Thanks for the info, in this thread and others. I was curious about a high flow cat also. A couple questions regarding it...How much do they typically run?? Also, with a high flow cat is there a problem with passing emissions tests, etc? Even though I live in FLA, I still want a street legal car and one that will pass any future tests should I have to go through them...Thanks for the help.

 

I had header and exhaust with stock cat, added a 2.25 high flow and the butt dyno noticed a difference. Think of it this way, you have this real nice exhaust and header with bigger piping for free exhaust flow, however it's got to go through this little restricted stock cat. IMO what good is an exhaust when it still has to flow through the stock cat.

 

Hi flow cat will let u pass emission(sp).

 

kteller.com sells prewelded cats for whatever setup you have for $150 plus shipping. its one of the cheaper choices, not to mention he welds the flanges on there for you so you don't have to worry about fitment...