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Cat-less make a big diff?

mousemonster1232

mousemonster1232

New member
I was thinking about making another downpipe, or finding someone with the ability to that does not have a cat in it.

Is there a real advantage to doing so? Would it really change anything other than the sound?

For example one for street and one for racing.

Thanks.
 


not sure on actual statistics, but cats are very restrictive, even when new and not clogged at all, so by rights removing it has to add flow and flow usually increases power and performance.
 
wrong. cats are not very restrictive.

the only reason to not have a cat is to not have to worry about it clogging. other than that, doesnt do anything for performance or sound.
 
I find that funny actually, guess in a n a car that could be true. But in a blower or turbo car, removing the cat and muffler increases flow and horse power. I own a 16 valve car turbo, intercooled, with a ful 3" mandrel bent exhaust, no cat or muffler. I went from low 14s to 13.7 on low boost, plus all the cool kids going 7s to 12s are doing it.
 


For the poor guys with emissions testing they sell hollowed cheater cats, so you cam pass a visual inspection and I guess the hollowed part must be for weight shaving since flow is useless right?
 
Not to mention back pressure measurments on the Cats themselves are very minimal. If you clog yours and dont have emissions testing you can run without it to save the cash of getting a new one... But that just smells bad for everyone get a high flow cat in that case if your worried. You will convert enough to pass federal aftermarket requirements and not have to be concerned with back pressure measurements (as bio stated you dont anyways)
 
Bio248 said:
it doesnt do anything for performance or sound.
Click to expand...

First one...I agree.

Second...however...no. Going from a stock downpipe to a catless one makes a noticeable sound difference...and even more so when running headers. All of those setups were through a stock catback and you know how quiet a stock catback can be...it was quite a sound difference to know it wasn't stock.
 


Stock cat...I'd never run one just because I like to have it ruled out already so it isn't problematic. The catback however doesn't become restrictive until about 350 FWHP...yes.
 
alll that i can think of is how many miles is on ur cat. if it issemi cloged yes you will notice a slight difference in sound and accleration. but nothing more then if you bought it off the show room with 0 miles on the cat. now like kody was saying they do become restrictive over 400 hp give or take around 50 hp
 
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