Headers Cats questions

mredwin25 · Wed, Sep-23-2009, 03:58:30 PM

Quote:

Originally Posted by EricSMG

Just race cats, mainly to be legal and reduce the smell. On a side note, I couldn't get that RE pipe to seal in my car..... it's just flat too short. Probably a combination of my particular car's tolerances and the Evosport headers.

That said, the RE pipe is a nice piece in that it's mandrel bent and seems heavy duty, so I'll most likely use it for my cat install. I'll just swap the resonators for race cats

The RE pipe looks like a very nice piece but I had many issues with cracking at the brackets that keep the two pipes toghether, the just kept cracking and cracking time after time.

EricSMG · Wed, Sep-23-2009, 04:34:28 PM

Quote:

Originally Posted by mredwin25

The RE pipe looks like a very nice piece but I had many issues with cracking at the brackets that keep the two pipes toghether, the just kept cracking and cracking time after time.

Mine just flat won't fit right.... too short.

mredwin25 · Wed, Sep-23-2009, 04:55:29 PM

Yeah I know, seems to me like there is always an issue with those. Just cut the resonators out and weld them to your stock pipe.

mredwin25 · Wed, Sep-23-2009, 04:59:00 PM

I think I'm gonna go with 400 cell cats, if oem's are 600 cell and race are 200's, I think 400 would be a happy medium, will help with the rasp, flow better than oem's and also help with the smell. I didn't know that those were so short in lenght about 3 inches that's really not much compare to oem's at about 10 inches. I think that 400's will be a great improvement. Don't you think?

EricSMG · Wed, Sep-23-2009, 05:04:38 PM

I think so but I'm a maximum performance kind of guy so I'd go with the 200s personally. But to be honest I doubt there's any tangible difference.

normcaldwell · Wed, Sep-23-2009, 05:06:03 PM

Quote:

Originally Posted by Custom Performance

The cell count in a cat is more a function of the length of the cat as opposed to the structure of the catalyst. The picture below is a Magnaflow metallic substrate 200 cell cat. While the metallic substrate is the same type of catalyst used in the OE cat U.S. spec) the length of the OE cat is about twice the length of the 200 cell cat. The body of the 200 cell cat is 3-inches while the body of the OE cat is about 10 inches.

The difference in length of the 400 cell and 200 cell cat (the 54000 D-shapes series I use on the CRT) is about 1-inch. So, in terms of rasp elimination, you can argue that the 400 cell will do a better job, but not by much.

Thanks for the info and clarification!

normcaldwell · Wed, Sep-23-2009, 05:11:18 PM

Quote:

Originally Posted by EricSMG

Just race cats, mainly to be legal and reduce the smell. On a side note, I couldn't get that RE pipe to seal in my car..... it's just flat too short. Probably a combination of my particular car's tolerances and the Evosport headers.

That said, the RE pipe is a nice piece in that it's mandrel bent and seems heavy duty, so I'll most likely use it for my cat install. I'll just swap the resonators for race cats

Yeah, when you weld in the race cats you can adjust length enough to get the seal. I'm surpised that it didn't seal between the Evosports & the stock section 2. You have stock section 2 and stock muffler; correct?

It'll be interesting to see if you feel any performance difference with the cats. I know you'll smell a difference!

normcaldwell · Wed, Sep-23-2009, 05:14:13 PM

Quote:

Originally Posted by mredwin25

I think I'm gonna go with 400 cell cats, if oem's are 600 cell and race are 200's, I think 400 would be a happy medium, will help with the rasp, flow better than oem's and also help with the smell. I didn't know that those were so short in lenght about 3 inches that's really not much compare to oem's at about 10 inches. I think that 400's will be a great improvement. Don't you think?

I suspect that, no matter what cat you use, you'll still hear some rasp if you don't have the additional resonators.
If having no rasp is very important to you, I still suggest one of the Custom Performance products that have cats and resonators.
Of course, you could try it with cats, see what you think, and go from there.

mredwin25 · Wed, Sep-23-2009, 05:55:39 PM

Quote:

Originally Posted by normcaldwell

I suspect that, no matter what cat you use, you'll still hear some rasp if you don't have the additional resonators.
If having no rasp is very important to you, I still suggest one of the Custom Performance products that have cats and resonators.
Of course, you could try it with cats, see what you think, and go from there.

Well I'm not taking off the resonators, they're staying just adding cats.

normcaldwell · Wed, Sep-23-2009, 06:11:48 PM

Quote:

Originally Posted by mredwin25

Well I'm not taking off the resonators, they're staying just adding cats.

Oops, sorry. I see that in your first post.

Wed, Sep-23-2009, 05:04:38 PM	#25
EricSMG 30 something Join Date: Nov 2008 Posts: 6,567 Reputation: 0 Location: San Diego	I think so but I'm a maximum performance kind of guy so I'd go with the 200s personally. But to be honest I doubt there's any tangible difference. __________________ *'98 Cosmos M3/4/5 \|\| '01 330Ci 5MT*

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Wed, Sep-23-2009, 04:55:29 PM	#23
mredwin25 Registered User Join Date: Jun 2007 Posts: 2,721 Reputation: 0 Location: Broward	Yeah I know, seems to me like there is always an issue with those. Just cut the resonators out and weld them to your stock pipe.

Wed, Sep-23-2009, 04:59:00 PM	#24
mredwin25 Registered User Join Date: Jun 2007 Posts: 2,721 Reputation: 0 Location: Broward	I think I'm gonna go with 400 cell cats, if oem's are 600 cell and race are 200's, I think 400 would be a happy medium, will help with the rasp, flow better than oem's and also help with the smell. I didn't know that those were so short in lenght about 3 inches that's really not much compare to oem's at about 10 inches. I think that 400's will be a great improvement. Don't you think?