ok, I've read the sticky post and have read most of the posts after it. i am lookng for a Nice set up for my Z with dual cats. If anyone knows Where I can get good headers (1 3/4") and a real honest to *** good y pipe for my dual cats help would be greatly apprciated. I added dual Catcos, and a hooker cat back but it's uses less when they are spliced in 2 1/4 an 2 1/2 factory piping. And none of the muffler shops in my area are competent enough to make such things. They can't bend over 2 1/2 and can't mandrel. I would like to have 3" all the way back...PLEASE HELP!

P.S. I assume most of you here have the single cat set up from what I can tell....

 

I'm in the same boat, everyone makes cat-backs and headers, but no y-pipe for dual cats. I've got catco converters on mine as well. For headers, I've got edelbrock...their o.k. I got them for $299 at TPIS several years ago. I think edelbrock and SLP are the only ones that make headers w/ AIR, maybe hooker. If I had to do it again I might go with SLP.

 

I have shot off an e-mail to Mufflex, after looking at their non emmisions legal Y pipes I figure maybe they might know of a custom solution, or actually offer somthing custom built, or know some other resource that can get it done for me.....Patiently awaiting correspondence....

Still no ideas from anyone here...?

 

I have a dual 3 inch system. From the header's to the dual cut-outs to the dual cats. Though I dont have a y-pipe for it, they made a cheap conversion. Hopefully later I can get a dual 3 inch in and single 3 inch out y-pipe
Peace Out,
PsychoGTA

 

Very nice Psycho, but that was all custom dine correct? Which leads me back to the competent muffler shop in my area, which does not exist. i would like something similar to that on my car...
I am wondering if all the work is worth it....i guess to me it is..

 

Yes the system is custom. I think i've seen a web site that sells mandrel bent pipes. If you search in the web, you'll probally find the pipes you need. good luck bro
Peace Out,
PsychoGTA

 

Any particular advantage/gain with a dual cat like you have them set up? What I mean is, Y pipe then dual cat and then Y pipe down to single pipe again...

 

Well the set up itself was supposed to be worth 10 hp over the single cat set up. I guess it would probably be the equivilent to an H-pipe. The way i understand it is that cats themselves are supposed to be restrictive, so by adding a second one it gives the gases another place to flow thru thus reducing back pressure. Am I wrong in assuming this? And would it be more cost effective to downgrade to a single cat?

 

There's nothing wrong with running a single 3" cat over the dual cat setup, with a -good- y pipe there will really be no huge power difference.

Before I get people going off on a tanget quoting the HP claim, stock to stock yes there is a difference. It's that the stock 3" cat setup y pipe is absolutly terrible. If you have ever looked at one off the car and a dual cat y pipe side by side, it's easy to see why the dual cat style sucks up less power. I would do the 3" slp headers that come with a great y pipe and use a single 3" cat. That's what I ended up doing, and I had both setups to chose from at the time. HTH!

 

I built my own setup using the Flowmaster Y pipe you can buy from Summit and you will need to buy 4, 45* mandrel bends. It also helps if you have access to a MIG welder. I found the best place to buy the 45* bends (believe it or not) J.C. Whitney. No one local to me does mandrel bends, and the 6-8 companies in the US who do, will not do small orders. I called them all. So I said f*** it I'll do my own and it turned out beautiful. Even bought extras so I made a catless Y pipe for after the E test I can run with out cats

 

That's exactly what I need to do. I have the single 2.25" cat setup now, but I'm changing to dual cats and it'll have that Flowmaster Y-pipe. Unfortunately, my header crossover pipes are 2.25" and the cats I bought are 2.5" so now, in addition to the 45* mandrel bends, I have to find adaptors to make the transition from 2.25" to 2.5" which I'm having a hard time finding.

 

I don't know if this helps any of you but there is still supposedly a y pipe Flowmaster makes for the dual cars from the cats back. You'll still have to buy some 2.5 bends or get a shop to make the bends from the headers/manifolds. Its #FLO-16078 and I think Summit still sells it (about $30-$40) but not sure??? 2.5" dual pipes curveing into a 3" outlet. later

 

I don't know if this is a dead issue or not, but Thunder Racing (yes, them at the top) have these SLP stainless steel adaptors that :

SLP's stainless steel adapters allow you to bolt their headers to your stock catalytic converter. Their complete installation kits include: Graphite coated, stainless steel crush ring headers gaskets, A/C bracket for 82-87 Camaro/Firebird (#30018 only), header bolts, fire sleeves, mounting hardware and installation instructions.

and the following part looks to be what you're looking for :

28-30024 SLP Header accessory kit, 1989-1992 Dual Cat F-Body

if someone has actually done this, I would be curious how it came out as I have a stainless cat system and would consider SLP headers if this went together well...

 

It looks like the only way dual cat with headers is going to work, is a custom setup. Noone seems to want to invest into this venture.


well, obviously besides SLP.

 

Well I have a 91 gta, 5.7L.... and have a dual cat setup, I was done by the guy who had the car before me, BUT mine runs separate 3" pipe from each hedder into each cat, then after the cats it joins to the single 3" into the transverse muffler.

The question is: Should I replace the existing with new stainless steel custom done a muffler shop, or would it be really expensive???

OR should I just replace it with a y-pipe into a good single hi flow cat?


Any ideas?

 

I'm curious as to why you would want to change? It sounds like you have a nice setup the way it is now, no?

 

lol.. sorry I forgot to explain that part... actually the reason I asked is because the y pipe going from the hedder to each of the cats is rusted and exhaust is leaking bad there so it sounds like crap. And secondly I believe those 2 cats are stock, so very they are very old. And from what I read you guys suggest that 1 hi flow cat should flow better than 2 old stock ones. Or do you think it's better of just putting 2 hi flows?

 

Im looking at the same thing... I have a 1989 firebird formula 305 TPI, 5 speed and I need exhaust. My car came with and currently has dual cats. It needs to remain emission legal.

I have found someone who has a 3 month old exhaust for a camaro / firebird 82-92.... Flowmaster. 3 inch from the headers to the muffler tips...
(Everything except the headers.)
It was on a carburated motor. Just wondering, it is only single cat, and 3 inch mandrel bent. Would this harm my emissions? How hard would it be to match it up to my stock manifolds?


Would it be more restrictive than stock?

Thanks for the help

 

Jim91z-You can find 2.5-2.25 or just about any combo reducers from jegs, summit any place like that that has a good selection or exhaust accesories.

 

I think you're asking if its a single pipe BEFORE the cats? No, there are two pipes, one for each side of the engine, each side goes thru its own cat, and then it joins together AFTER the cat.

SLP's y-pipe is only 2 1/4", which isnt great. I made my own 2 1/2" custom y-pipe setup for my car and my son's car, but that doesnt help you. Sorry...