Tracking down a 3 inch cat?

[GstGeorge3]

Hello everyone... this is my first post and im sorry if this has already been addressed before so just let me know if there is a thread on this but.......
Im putting together an exhaust system in my head for my 97 gst. Its basically stock except for an intake and a 1g bov. I was thinking of doing a 2.5-3in downpipe... 3in cat...3in Greddy evo2 catback. So here is my question to all of you: Does anyone know of any places that sell a 3in cat that has flanges on either end? It seems like most companies make a 3in to slip fit. So is there a reason why its so hard to find a flanged 3in cat?? Correct me if im wrong, but ill need one for the greddy catback right? Also, what are everyones opinoins on slipfit vs. flange bolted?
Just out of curiosity, will this combo make a problimatic amount of boost creap? I dont have the o2 housing ported. The downpipe will remain 2.5 until after the flex section.

Any thoughts or links to posts that already address this would be greatly appreciated.

-George

 

[andymoraitis]

George,

Howdy and welcome to the site. You can find a flanged 3" high flow cat from Road Race Engineering. Here's a link with more info:

http://www.roadraceengineering.com/eclexhaust.htm

And no, a 2.5" to 3: will not aggravate boost creep. Usually, it's the 3" downpipe/testpipe setups that have boost creep issues, but only with certain turbos (i.e. the EVO III). As far as preference, I like flanged, since I've never had an issue and leaks are easy to detect and fix. Fully welded with no slip fit or flange is even better.

Enjoy!

Andy

 

[speedy_talon28]

Well, I got my high-flow cat off ebay that had flanges for around $30.00

 

[andymoraitis]

Well, I got my high-flow cat off ebay that had flanges for around $30.00

Most of those are nothing more than test pipes sold as high flow cats. I'd buy from a reputable vendor, pay a bit more and know what I'm getting.

 

[GstGeorge3]

Thanks for the quick reply! One thing i noticed from that link is that their cats/downpipes say they are flanged for those catback systems only. So does that exclude the greddy one that i was looking at? I dont think it has a small first section..... but i could be wrong. What are your guys' thoughts? -george

 

[1glaserturbo]

I've got a somewhat used (around 5200 miles) full 3" cat that I'd be willing to get to you for $50 shipped.



Chris


Pictures if you want, I'll post them.

 

[andymoraitis]

George,

Use the flange on the DP mated to the front flange on the cat and have them weld the rear section of the cat to the remainder of the cat back. That's my setup and it works fine. That way, you don't have to worry about fitment and length as an additional sleeve can be added that will join both sections if the cat isn't long enough.

It's not like a cat needs to be changed every couple of years and when it does, they can simply cut the rear section, make a new sleeve and you're good to go again. The sleeve and welding cost me $20.00 at a local muffer shop. This also give you the flexibility to drop the downpipe and do transmission work without having to worry about cutting up a fully welded system.

You may also want to go to http://www.summitracing.com and take a look for some flanged high flows (front section only) where you can weld on to the back. I believe they stock Catco and those work fine. You can also find more information by searching for Random Technologies. I had a Random 3" high flow. Do some web searching and you'll find what you're looking for.

Andy

 

[TheRealist]

just go turbo back, much better

 

[andymoraitis]

just go turbo back, much better

Maybe he cares about emissions?

 

[GstGeorge3]

Yeah, i want a cat because i actually care about the world, plus illinois has testing and id like to be able to drive this thing legally. hmm, i wonder how off the bolt pattern is betweend the cat and the greddy cat back. Thanks andy for your advice, i might go that route. But just incase..... Is there anyone out there that has a Greddy evo2 catback and still uses a cat... at all 3 inches?

 

[DiemondJ8383]

http://www.kteller.com/store/product_info.php/cPath/23_25/products_id/220 . They let you choose what kind of flanges you need.