5.7 single cat I-pipes and 3.8 I-pipes

[Jaymatic]

From what I have heard, I think the 93-95 single cat 5.7L's I-pipe is identical to the 3.8L's except for the fact that it is 2.75". Is this correct?
Do they both have that S-pipe?
Do they both weld up to the cat?
Is the stock V8 cat the same length as the stock V6 cat?
This site ( http://www.maremont.com ) says that the z-28 I-pipe is 76 5/8 and the 3.8 I-pipe is 65 3/8. Is this a problem? You can check out a lot of the specs through their e-catalog section.

My 3 options are: 2.5" inlet dual 2.5" outlet Dynomax Super Turbo muffler 1.) With a reducer from the muffler to the stock I-pipe, 2.) Crimp-bent 2.5" I-pipe, or 3.) This z-28 I-pipe.
If it will work, I am opting for option number 3 right now but don't want the popping and raspiness associated with a 3" I-pipe on a stock 3.8L. Would a z-28 I-pipe be the best way to go? It would still be going from the 2.75" pipe to the 2.5" muffler.

[99W68Firebird]

yea, looks like your wanting to do same thing i do... i have

1) Pacesetter Headers with 3" oulet on Y-pipe.
2) 3" in/out Hi-flow cat
3) 2.75" I-pipe off Z-28
4) 2.50" in/out Flowmaster 80 series

my mechanic said something bout a S-pipe. so im just gonna have him install the headers and y-pipe then take it to exhaust shop and he said he'd hook up all the rest of it for $65. so i dont know what hes gonna do to hook it all up but im gonna let him do whatever he has to and not worry about it.

[kamarozrule]

Originally posted by 99W68Firebird:
yea, looks like your wanting to do same thing i do... i have

1) Pacesetter Headers with 3" oulet on Y-pipe.
2) 3" in/out Hi-flow cat
3) 2.75" I-pipe off Z-28
4) 2.50" in/out Flowmaster 80 series

my mechanic said something bout a S-pipe. so im just gonna have him install the headers and y-pipe then take it to exhaust shop and he said he'd hook up all the rest of it for $65. so i dont know what hes gonna do to hook it all up but im gonna let him do whatever he has to and not worry about it.

im just curious but why didnt you go with a full 3" exhaust???

[DARK SDE '02]

I thought the basic shape of the I-pipes were the same for V8s and V6s on any 4th gens? It's just that the V8s are larger diameter, I guess I could be mistaken. What's different is like you said, the dual cat V8s and the single cat V8s and how they connect to the I-pipe. I have the SLP 30045 s-pipe kit for my car, it's 3", and it was originally designed for the LT1s to fit the LM.

And I'm curious as to why you'd ween out your exhaust like that too... do you want more back pressure or what?

[Jaymatic]

Well I originally wanted to 2.5" I-pipe cause a cat-back is going to be my only mod. So I don't really need 3" on the stock engine. It is just hard to find a 2.5", and no one around me mandrel bends, I would have a good hour to drive in order to find a shop that might mandrel bend. So I thought that maybe a Z-28 I-pipe would be better than a 2.5" crimp bent pipe. Both pipes would be crimp, but the Z-28 would be a 1/4" larger, giving me more flow. A 2.5" crimp bent pipe wouldn't really be too much of an upgrade. There would still be quite a bit of backpressure at the bends.

[99W68Firebird]

kamarozrule, i did that because of back pressure, heard really only need full 3" exhaust system if you have turbo or NOS

[DARK SDE '02]

The sound of a 3" exhaust is always deeper and louder as well as better flowing than small diameter piping. I plan on turboing my car so I wanted the highest flow possible with a cat-back. But really, the smaller sized cat-backs aren't any cheaper than a 3" so why not just save yourself the trouble down the road and get it now? You still have plenty of backpressure especially if you have a real muffler and a stock cat.