Which exhaust mods ???

delling3 · Dec 30, 2019

Ok, trying to come up with a "plan" for my '96 GT.

NPI motor with PI intake and cam swap. Otherwise, currently stock, including exhaust. Considering going with a Pypes catted X-pipe, and Pype-Bomb cat back. I know a off-road x-pipe is both cheaper and will make more power, but I am thinking of keeping the car "legal", even though my state doesn't do emissions testing.

Anyone have any idea if the catted mid-pipe is worth doing? My current cats are not causing any issues. I know the aftermarket part will be lighter, and will flow a bit better, but questioning if the difference will be noticeable - particularly if not doing a tune?

96blak54 · Dec 30, 2019

In my opinion if the car has cats, run the exhaust straight out...no muffler. The cats smooth out the pulses and sort of muffles the tones.

I guess this all depends how loud you want it.

Jakespeeds · Dec 31, 2019

Its all up to the air pump under the hood. You might feel a little more power maybe. You will probably notice the car will pull a little harder and for a bit longer before the power drops off.

Exhaust at this point for you will probably just make the car sounds a little more rumble rumble. You would need to do headers to make full use of an exhaust. And even then the NPI heads and cams will be a stopping point.

For the "legal" part consider a no cat X pipe then keep your factory midpipe around. Its what I do here in California. Just put it back on the car once every two years with the factory tune. Everything else on the car is CARB certified. But you will need a way to switch off the back O2 sensors with no cats. I never had any luck with those plug in simulators. Maybe you will fair better. I do mine with a tune.

Jake

delling3 · Jan 1, 2020

Mainly, I want to wake up the exhaust note a little bit, I realize the performance adder will be minimal. Maybe I skip the mid-pipe all together, and simply do a cat-back. I think that the PI cams and intake, along with a set of 3.73 gears in the differential will keep me satisfied for a while performance wise.

95opal · Jan 1, 2020

Biggest restriction in the factory exhaust is the catted mid pipe. I would swap in an off road pipe before doing a cat back.

RAU03MACH · Jan 1, 2020

The cats are the biggest restriction in the exhaust
I have seen some cats that are free flowing
A performance cat
Just can not remember the company that makes them
These would be recommended to those that have emission stickers
I took all mine off
To me its useless crap
Every tree hugger will want a Whaambulance

white95 · Jan 1, 2020

Long tube headers really wake these cars up. The peak gains may not be impressive but the under the curve gains are excellent.

01yellercobra · Jan 1, 2020

FWIW, I cleared 600hp with cats. I'm probably close to it again with those same cats. From what I've seen/read there isn't much power difference between good high flow cats and an O/R pipe. This one might be worth letting your wallet decide.

But don't forget cats muffle as well. When my old cats blew out I essentially had an O/R pipe with Stingers. Way too loud for me so I installed new cats. Plus I'm not a fan of the fuel smell anymore. But then a buddy has an O/R X pipe with full Magnaflow mufflers and it's pretty tame.

ttocs · Jan 1, 2020

all this talk about exhaust and no one has mentioned my favorite exhaust mod, the electronic cut out. Why not?

01yellercobra · Jan 2, 2020

ttocs said:
all this talk about exhaust and no one has mentioned my favorite exhaust mod, the electronic cut out. Why not?

The buddy I mentioned has them. Someone revved at him once when we trying to get in line for a show. It was funny to watch the guy jump after my buddy opened the cutouts and revved back.

ttocs · Jan 2, 2020

01yellercobra said:
The buddy I mentioned has them. Someone revved at him once when we trying to get in line for a show. It was funny to watch the guy jump after my buddy opened the cutouts and revved back.

it is always just that much fun almost every day. Instant attitude at the push of a button.

01yellercobra · Jan 2, 2020

ttocs said:
it is always just that much fun almost every day. Instant attitude at the push of a button.

I've toyed with the idea of switching to full mufflers and installing cutouts for ghee times I want loud. But then I punch it and fall in love with my Stingers again.

Fast Lane · Jan 2, 2020

2V cats are not restrictive. Nothing a dyno could ever measure. The exhaust manifolds are restrictive. Its not the 1980's anymore...

TrickVert · Jan 2, 2020

With your mild mods, you will see zero effect going to hi-flow cars or an O/R pipe (except for the stink that will result). And for those who think a non-catted H or X is best, do your research. Today's hi-flow cats induce negligible power loss for 99% of street-driven setups.

I'd suggest a set of mufflers to wake up the sound to the degree and tone you want, and put the x-pipe money toward the gears you mentioned. That will wake up the car far more than any exhaust mod you could do. Exhaust at this point will be a "music" mod measured in smiles, not HP. Magnaflow is a popular choice, but there are myriad options.

RAU03MACH · Jan 3, 2020

On my 97 cobra supercharged I went with JBA shorty headers, no cats H pipe off road , supper 44 flow masters , its definitely loud
Glad I did not put the 10 series on it