I have a '91 Z28 with dual cats, I recently put on the FLOWMASTER AMERICAN THUNDER system, while i was under the car i notices the pipes between the cats and exhaust manifolds were severly crushed, i know these pipes have never been replaced so i am assuming that this is a stock crush bend. I fould a catco kit #CTO-4153 it comes with dual cats and from the pic it seems to come with new pipes to the maifolds. Would this be a wise investment? Has anyone ever used this of know if flows much better than OEM? I would like to have the exhaust be a little louder and I know that OEM cats can restrict flow a little.

 

Don't bother, get some shortie headers. I'd only get the catco kit for the dual cats, because it's a bit cheaper than buying the 2 cats separately, IIRC.

 

Carsound also makes a stainless steel mandrel bent replacement Y-pipe, that bolts to the OEM exhaust manifolds, including 2 high flow cats and is 2 1/2 all the way. Just another option.

 

You could also get a single cat header/y-pipe kit and a single 3" cat.

 

hey VA1991Z28 where could I order the carsound kit from, because I looked at the carsound website but they have no prices on any of their products? Just curious, are you running these cats on your car or know anyone that is?

 

Here is the link

http://www.car-sound.com/catalog/dir...spx?PartID=218

part # 23479. I paid $365.55 for everything delivered to VA. Pricey, but for stainless steel mandrel bent 2 1/2 pipe running the entire way + 2 carsound high flow cats, I went for it. I have to pass emission testing here and don't want to worry about it, so I need the cats. I have it sitting in a box here, having injector issues right now. FYI - make sure that the car isn't having any other issues (leaking injector, O2 Sensor etc..) before replacing cats, since I burned up one of my Random Tech cats because of bad O2 sensor. This entire package (Y-pipe + 2 high flow cats) is still less than I paid for my 2 Random Tech Cats. Lots of other members are running Carsound cats, search on that and read what they have to say about them. Good luck.

 

FWIW, if you ever get shorty headers, those y-pipes you just paid for gets thrown out. If you're planning on headers, just keep your stockers until you get headers, then get some high flow cats to go with it.

If you're never going to get headers, then these direct-fit replacements with y-pipes will do you just fine.

The catco kit is OK, the after cat y-pipe kinda sucks, but with the flowmaster kit you get a better pipe anyway. They need to be cut and welded on to or clamped to the flowmaster system.

 

Thanks - but I wasn't planning on doing headers. Where the 2 pipes merge into 1, the output pipe ID is 2 1/2. I plan on getting that stretched to 2 3/4 or so, the walls seem thick, and connect (weld) it to a Banks cat back.