exhaust question

[redws6rocket]

hi guys i am new and was wondering if any one has ever tried this exhaust set up. i tried a search last night and coudn't find a match. any way i have a 94 3.1 gt i want to cut my rear mufflers off and weld in a piece of pipe were the went and then cut off my resonater and put a bullet style muffler or a glasspack. don't want anything real loud just want cheap easy power and better fuel mileage. any help would be great thanks in advance. steve

[bobgagt]

I removed my mufflers and ran pipe to two tips... not much of a power / mileage gain unless you increase pipe size and get rid of the resonator. The sound is good. Your idea sounds good just use 2.25" or 2.5" piping and maybe change out the cat for a hi flow one... then you should notice a difference.

[BBT]

I dunno about the 94 & 95 GAs, but the newer ones have pretty good flowing cats and a change to a high-flow is about pointless. In your case, just getting a new cat might be a good idea, for if yours is the original, then it may be beginning to get clogged.

In any event, these cars do not gain much in the way of HP by just doing an exhaust. You need to do other mods. And if the example of a 3.1 Monte Carlo running around here that has 2 glass packs in place of mufflers is any indication, it will sound like tinny shit.

Just my opinion.

BTW I have done a cat-back, with resonator removed and two performance mufflers. Great sound, but not really much more in the way of either performance or gas mileage, although the butt-o-meter said it felt faster.

[redws6rocket]

sorry guys maybe i didn't say it clear enough. i will my stock cat converter and cut off the stock resonater and weld in a glasspack in its place. then cut off the mufflers and weld in a pieces of straight pipe were the mufflers were. any one every done.

[BBT]

I think you will end up with loud, not good sound (see my previous post) and little or nothing in the way of more power and gas mileage.

Let us know how it turns out. Maybe it will give you what you want.

[bobgagt]

Stock resonator basically is a glass pack... and mine sounds great with stock cat, res, and no mufflers... not too loud with a dang nice tone imo...

[Matt95GT]

A buddy of mine tried at least 4 different exhaust setups on his 95 3100, including what you describe - which resulted in the least performance gain of all his exhaust configurations. If you wanna avoid it being loud, this is not the setup for you... it is very loud.

[redws6rocket]

all right i bought a glasspack muffler from www.racerpartswholesale.com the twin tube turbo one that says is quieter than a normal glasspack so will get this installed here in a week or two. do you guys think i should keep the stock resonater on too or just put this in its place with no mufflers.

[bobgagt]

Glasspack with stock cat / res DOES sound like ass. I KNOW that much. Id replace the res with the glasspack and run straights out and see how you like it. Mine isnt too loud and it has a good tone... I'll have to get a sound clip of it.

Matt I'm redoing my exhaust and I thought you ordered a bunch of mandrel bends off the internet... where did you get them from and what bends are needed? I'm gonna run pipe from the catback into a single in dual out muffler like 95gt did on his car.
Sorry for goin off topic.

-Bob

[Matt95GT]

Originally posted by bobgagt

Matt I'm redoing my exhaust and I thought you ordered a bunch of mandrel bends off the internet... where did you get them from and what bends are needed? I'm gonna run pipe from the catback into a single in dual out muffler like 95gt did on his car.
Sorry for goin off topic.

-Bob

Not sure, I took my car to a shop with a mandrel bender to have it fabricated. (had to go out of state to find one, lol) But... you can find mandrel bends at summit racing. They were labelled for building headers, but have any diameter. I used them to build my intake.

[bobgagt]

I wonder if the mandrel catback piping from mantapart is legit... and if it wouldnt take a year if I ordered it...

[Matt95GT]

Originally posted by bobgagt
I wonder if the mandrel catback piping from mantapart is legit... and if it wouldnt take a year if I ordered it...

Not sure... I asked about it when I called once. And yes, they'll sell just the midpipe.Thing is... I'm not sure how well it will fit considering it is meant for early Quad vehicles... Beretta's, GA's, etc. I strayed away cause I'm not sure if they accounted for the suspension change for 95-98.

[ChevelleSSLS6]

/\ I like matt's GAs a lot, especially those rims on that body style...
-another matt

[bobgagt]

Originally posted by Matt95GT
Not sure... I asked about it when I called once. And yes, they'll sell just the midpipe.Thing is... I'm not sure how well it will fit considering it is meant for early Quad vehicles... Beretta's, GA's, etc. I strayed away cause I'm not sure if they accounted for the suspension change for 95-98.

What is so different about the suspension between 94 and 95? I e-mailed mantapart and asked if it would fit a 98 and they havent gotten back to me yet. I hope it does...

2.25" should be plenty adequate for me.

[Azrael]

95's were a major transition year and used the same suspension that's on the 96-98 GAs. I think the biggest difference is in the rear though.

- Yet another Matt

[bobgagt]

Well I know 92-94 were same, and 95-98 were same... but I wasn't sure of what the exact difference was and why / in what way it would affect the exhaust setups on these cars... maybe if someone has two undercarriage shots (one from a 92-94 and one from a 95-98) for comparison... that would be kinda cool to see :)

[Matt95GT]

Originally posted by Azrael
95's were a major transition year and used the same suspension that's on the 96-98 GAs. I think the biggest difference is in the rear though.


Correct. Actually the front suspension remained the same in 95, only the rear changed.


Originally posted by bobgagt
... but I wasn't sure of what the exact difference was and why / in what way it would affect the exhaust setups on these cars... maybe if someone has two undercarriage shots (one from a 92-94 and one from a 95-98) for comparison... that would be kinda cool to see :)

The spring location / size changed. The main bar going across to both sides (whatever the hell you call that on a non-independant setup) looks different... possibly closer to the front on one. The stock GT exhaust transitioned as well for this change... the 92-94 use a main muffler (drivers side) that outputs to the secondary (passenger side) muffler. The 95 has a Y-pipe tucked up over the suspension feeding both mufflers.

I have to drive to my parents tonight, if there's not a few inches of snow/slush on the ground when I get there I'll try to grab some comparison shots.

[bobgagt]

Cool... thanks Matt. I knew the 92-94 had an interesting setup because I had to replace one muffler on my 93 3300 gt at one point and i was a bit puzzled. The drivers side muffler is huge, single in, dual out but one out goes over to a little tiny muffler on the passenger side. Mantapart isn't going to get back to me it seems so I'll just get it custom done I guess... anyways comparison shots would still be cool ;)

-Bob

[BBT]

My 95 had/has the setup described above. No Y pipe. Maybe the Y pipe setup phased in during 95?

[Matt95GT]

Originally posted by BBT
My 95 had/has the setup described above. No Y pipe. Maybe the Y pipe setup phased in during 95?

Doesn't surprise me. 95 was weird like that. Everyone I've seen has the y-pipe... but then there's all the other mid-year changes... OBD1.5 vs 2, cam position sensors on the Quad 4, etc. Plus, GM prolly needed to get rid of the remaining old dual exhaust setups.

[ChevelleSSLS6]

/\ very likely possibility; who really buys OEM replacement exhaust parts. It's either some local muffler shop "OEM Style" replacement, or a performance, or simply none at all.

GM prolly didn't want a few thousand "old style" dual eshaust setups, so it's safe to assume they said "get rid of 'rm!"

It would be interesting to start a "how many matts are there here?" thread.
-"another matt"

[BBT]

Originally posted by Matt95GT
Doesn't surprise me. 95 was weird like that. Everyone I've seen has the y-pipe... but then there's all the other mid-year changes... OBD1.5 vs 2, cam position sensors on the Quad 4, etc. Plus, GM prolly needed to get rid of the remaining old dual exhaust setups.

I think mine is the OBD 1.5 as well.

I had the OEM one pipe into big muffler out to small muffler before my performance exhaust, and after I replaced the performance exhaust.

When getting the exhaust done the last time, all the muffler parts books the shops looked at had that setup. None showed a 95 with a Y pipe. I'll bet you would have to go to a Pontiac dealer to get a 95 with a Y pipe exhaust setup.