HP diff from hi-flow cat and no cat.
Thread Starter
Registered User
Joined: Apr 2005
Posts: 1,830
From: Colorado Springs, CO
HP diff from hi-flow cat and no cat.
Does anybody know what the hp difference is between a hi-flow cat and no cat. I am moving to maryland soon and they have emmissions tests. Also will hi-flow cats pass in emmissions tests. Whats a good sounding/flowing exhaust to have with cats.
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Joined: Mar 2004
Posts: 643
From: St. Charles, IL
Re: HP diff from hi-flow cat and no cat.
???? 
Not quite sure what they are talking about.... but a GOOD high flow cat is is engineered to allow the same air volume as the b-pipe dispite the honeycomb, by making a calculated increase in size.
Not quite sure what they are talking about.... but a GOOD high flow cat is is engineered to allow the same air volume as the b-pipe dispite the honeycomb, by making a calculated increase in size.
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Joined: Mar 2003
Posts: 1,213
From: Milwaukee, WI
Re: HP diff from hi-flow cat and no cat.
well i got the eastern 3" highflow cat on ebay for about 40 bucks and it seams to flow pretty good, i got pulled over my the state patrol and got busted for no cat 
it seams like it isn't quite as fast though.
it seams like it isn't quite as fast though.
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Joined: Jun 2002
Posts: 214
From: DFW
Re: HP diff from hi-flow cat and no cat.
Don't know the exact hp differance but it's more power with no cat. I understand the theory but the airflow still isn't as straight and it slows down in velocity b/c the shape of a cat is a reverse venturri.
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Joined: May 2003
Posts: 886
From: Connecticut
Re: HP diff from hi-flow cat and no cat.
I'll be in the market for a high flow cat soon. Where do you put the cat on the exhaust, because as far are I know the y pipe connects directly to the catback. Do you just cut the length of the cat out of the y pipe and weld it in?
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Joined: Jun 2003
Posts: 3,620
From: Saginaw, Michigan
Re: HP diff from hi-flow cat and no cat.
The more HP you are making, the more HP a high flow cat will rob.
For example, the stock dual cats on an LS1 rob about 8 rwhp. The stock dual cats on a LS1 flow BETTER than a single high flow cat. So yes a single high flow cat can, and does, rob HP.
Here is a great article for you:
http://www.installuniversity.com/ins...n11.122001.htm
Dan
For example, the stock dual cats on an LS1 rob about 8 rwhp. The stock dual cats on a LS1 flow BETTER than a single high flow cat. So yes a single high flow cat can, and does, rob HP.
Here is a great article for you:
http://www.installuniversity.com/ins...n11.122001.htm
Dan
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Joined: Mar 2001
Posts: 2,521
From: Costa Mesa, CA
Re: HP diff from hi-flow cat and no cat.
I got a 3" universal high flow catalytic converter that's made by Random Technologies. It didn't seem to hurt my power any after I installed it (before I had no cat). I passed TN emmissions with ported heads and a HOTcam no problem.
Thread Starter
Registered User
Joined: Apr 2005
Posts: 1,830
From: Colorado Springs, CO
Re: HP diff from hi-flow cat and no cat.
So should i get 2 hi-flow cats and weld them into the y-pipe or just one and weld it in after the y-pipe. I was also going to get a cutout. Should i put this before or after the cat/s.