Need someone to set me straight...

[Cobra^R]

Hey, got a few exhaust questions. I wanted to ask you guys because i figured id get flamed and told to search. (which i did)

I have limited funds but i just would like some knowledge letting me know whats gonna be best. Is it best just keeping the stock piping (being i want 2.25, dont wanna loose low end torque with 2.5 being im not going engine mod crazy) , replacing the cat with a carsound(magnaflow) cat, and then just replacing the muffler with the flow 80 series? In that process, loose the Resonator also?

Or am i better off, keeping the current cats, loosing the Resonator, and running all new pipes (2.25) from cat-back? Just not sure if its worth replacing new pipes, if its gonna be teh same size, yet it may be a hassle keeping the stock pipe, i dunno?

If it helps, its on a 99 GT w/ 90k miles

Really appreciate the help!

[92CamaroRS]

throw a new cat on there with 2.25 or 2.5 back to a an 80 Seiries Flowmaster and then the tips of your choice and you will be more than pleased with what you have.

[Cobra^R]

If i may ask, what all will a new cat do? Guess since all the stock pipes 2.25, theyd just have to sawp the cat and the muffler. Should the resonator be left on also?

[92CamaroRS]

seeing as your car has 90k miles on it the cat prolly isnt in the best shape. replace it now so you know what you have and so it doesnt cause you problems down the road. i thought that stock pipe was 2". also junk the resonator.

[Colin]

Your GT's stock pipe is 2.25 already . And keep in mind it's stainless steel as well . If you have little or no mods , just get a Cat Back exhaust system and leave the rest of the factory system .

[Dan01GT]

I'm not too sure about the condition of you CAT or even the concept of junking your resinator. However, I'll tell you what I did on somewhat "limited funds" because I couldn't part with $500 for a cat back exhaust. I purchased a Flowmaster 80 Series Muffler on ebay (seller=performance peddler) for $83 shipped (U.S.). This muffler is the crossflow kind (1 2.5in., inlet and 2 2.25in. outlets), I'm assuming you have the same set up as I do. When I spoke to the Flowmaster representative he told me that although these mufflers are specifically designed for Camaros and Firebirds, aka V8's, they can work with V6 Grand Ams is adjusted properly. Because of the mufflers 2.25in. outlet, to make our cars sound good as well as perform good ther have to be sized down to 2in. I did this to my car and it sounds incredible. A nice little low burble at idle and even betted throaty sound under 2500RPM. Don't worry about people saying that going from 2.25 to a 2in. tip is going to cancel out any performance gain by restricting backpressure, like I was told. These mufflers are designed to flow better and for them to work properly you still need some backpressure. Either way, your car will sound alot better and even gain more horsepower, torque, and gas mileage with a performance exhaust. By the way, all said and done my exhaust purchase and installation cost me $300. $83 for the muffler, $70 for the tips, and $150 for the labor.

[Cobra^R]

Well, just from the cat back they say to run 2 inches?

[Dan01GT]

No not from the cat back. They told me that the stock piping (not sure of diameter) would be sufficent up until in went into the 80 Series. However, the piping coming off of the muffler, due to internal construction (baffolds) of the muffler to aid better exhaust flow had to be 2in. to keep the backpressure at a level that wouldn't deduct from any potential power gains. Basically, at 2in. (with that particular muffler) you can receive optimal performance with the set up that I have.

[matts]

from what i've heard, not sure on how true it is, is that these cars have a fairly free flowing cat to begin with, so a high flow cat would be a waste of money.....especially since you said you were on limited funds.

if it were me i'd leave the stock piping alone and run new pipe from the cat back to the 80 series. it's simple and effective :). now once you get a turbo and a plethera of other go fast mods THEN you need to worry about pipe size :P

[Old Guy]

You're right...the cat isn't really very restrictive. The restrictions in the GAs stock exhaust is from the extensive crimping over the axle and the restrictive muffler. Cat back is the best way to go. Whether you put a resinator on or not is personal taste. Depends on whether you want the exhaust note to be loud or not.

Personally I went with 2 1/4" exhaust with a Magnaflow 4" round muffler for a resinator and a Magnaflow Street Series at the back (single exhaust, not duals) You can replace the single agnaflow with a Camaro style muffler to get the duals on a GT.

[92CamaroRS]

well with 90k miles id replace the cat. not like its uber expensive. and a factory new one would cost just as much as an aftermarket free flowing one. about $90-100.

[litdevil316]

yea, i just got a new cat on for free(bout a year or so ago), EPA warrenty, and if i would had to pay, it would have been a free flow. they wanted to charge like $200 some for a new cat and all. some after market freeflows i seen where about $150

[Cobra^R]

Well, ive seen the carsound (magnflows) on ebay for $55, i might go with that. So it looks like use to the stock piping (2.25 from cat back, then the 2 outlets going to the tips im gonna go from 2.5 outlets to 2" pipes? I guess it seems kinda right, but thats teh first time i read that over the hours and hours of reading up on everything

[digital-d]

Get the hi flow cat only if your going with larger than stock piping, it won't restrict the exhaust as much. I see your staying stock though so it really isn't worth it.

[coupe]

Prices on those cats are pretty high. Mine was $35 at performancepeddler.com. Its a highflow carsound (magnaflow) cat.