Thread: Any short, quiet(ish) mufflers for '97-'03 GTP?

When I knew my exhaust was rusting out, I bought Walker OE-style mufflers and a TruBendz stainless 2.5" piping kit that fits the stock location.


Mufflers fell off before I could get to it. Now I need to get it driveable.


Unfortunately, I found the TruBendz piping kit is not compatible with the Walker OE-style mufflers.


97-03 Pontiac Grand Prix Dual Exhaust Tubing - 2.5 Inch Stainless - TruBendz Technology


It's 2.5" like the OE, and fits around all the bends the same, but where the "Y" splits, it extends about 3 or 4 inches farther back than the OE pipe. Also the radius of the elbows is larger. So this pushes back too far to fit the long OE-stle mufflers. Also, the TruBendz kit exits at 2.5" unlike the OE that reduces to about 1.875" after the split.


So I need to either...


- Get the Walker midpipe, which I'd rather not do because it is aluminized and crush-bent
- Modify the back of the TruBendz kit (that is, pay someone to modify it)
- Get shorter mufflers with a 2.5" inlet


I don't really want "loud." Don't really like the sound of 3800's, plus it is a daily driver I sometimes lend to my kids when their cars need work, and they definitely don't appreciate "loud."


Are there any shorter mufflers that are on the quieter side? As close to OE as possible, but I realize most of what's available would tend to be louder than stock.


I'd prefer to have the piping modified, but it might be cheaper to go with different mufflers, if I can find something acceptable.

Originally Posted by Bronco Boy

Option 1: modify the TruBendz pipe to work.
Option 2: have exhaust shop bend a new pipe to your specs.

Those options I know. I was asking about mufflers to compare the price vs. modifying the TruBendz.

Originally Posted by Bronco Boy

I deleted my comment about mufflers..... I would not look for a smaller muffler. They will sound like crap on our cars. You already said that you don't like the sound, so don't make it worse. LOL

That's about what I expected, but wanted to check.

My general plan (before the mufflers fell off) is, open up the intake to hear a little more supercharger whine, and keep the exhaust quiet enough that it doesn't drown out the whine.

If you've got any junkyards around check there. I got a factory catback at my local that was still in good shape.

Hmm...

I looked at the ZZP 2.5" cat-back, which is direct bolt-on.

3800 Parts 2.5" 97-03 Grand Prix Stainless Catback Exhaust

I noticed the muffler hangers are on the sides of the muffler rather than extending beyond it as the OE-style muffler.

WALKER(R) EXHAUST SYSTEMS :: E-Catalog Lookup

(Walker's picture is upside down.)

The tips on the ZZP are also right up against the dual-out muffler. This means the mufflers should sit farther to the rear than the OE system.

Welding new hangers to the sides of the Walker mufflers (so they can sit farther back) might be another option to allow the TruBendz kit to be used without (much) modification, but it depends on the Walker mufflers being vertically short enough to clear the body, and also allow tips to sit at the correct height. I suspect there's a good chance they would sit too low, but I'll have to get out under the car and measure things. I'm sure the ZZP mufflers are vertically shorter than the Walkers, probably shorter lengthwise too.

Or just buy the ZZP kit, sell/return the other parts, and live with any increased noise/drone. Probably wouldn't be worse than my old droning rust-hollowed mufflers.

Originally Posted by Scottydoggs

zzp kit is way loud.

Thanks. There are reviews saying it's quietish, so I will ignore those and pass on the ZZP.

Originally Posted by Scottydoggs

this is what i bought, and who i got it from as well off ebay. 1997 - 2002 Grand Prix 3.8L Muffler Exhaust Pipe System Kit | eBay

What can you tell me about that kit, after seeing it yourself? Do you know whether that is aluminized or stainless? Crush-bent or not?

I've actually sent them a question about another part they had listed, just the mid-pipe, but they don't seem to know any specs, just "send us your VIN so the computer can tell us if it fits."

Ooh, found another "gotcha."

6th gen is 97-03, 7th gen is 04-08.

BUT...

It appears Pontiac changed the exhaust for the 03 model (last 6th gen year) and continued it into the 7th gen (for models with dual exhaust.)

I noticed this when looking for aftermarket systems. Some showed compatibility with 03-08 and others 97-02.

So I looked up various years on walkerexhaust.com.

Up to 02, the mid pipe is 2.5". For 03 and after, it is 2.25".

The outlet at the cat, and the inlet for the resonator, is 2.5" for both. But up to 02 the resonator outlet is 2.5" and for 03 up it is 2.25".

Did anyone know this? I haven't seen it mentioned anywhere that 03 reduced the exhaust diameter.

Stay away from Walker if you live in the North! I did a Walker cat back and it lasted one winter and both mufflers were completely rotted and outer layer fell off. Did a warranty swap and second set lasted less than 2 years before rusting completely through and one rusting off hangar. Mid pipe had rust holes at all the welds. Terrible, terrible quality. I live a half hour from Walker's HQ and I wanted to drop off the rusted out mufflers at their front door and show them what "quality" their product is!

I ended up going with ZZP resonator, ZZP pipes, and Solo Performance Stealth Muffler. Quiet as stock but a little deeper tone. It is perfect! So far a year later no rust holes! Amen! Tired of doing my exhaust.

Originally Posted by brettstoner

I ended up going with... Solo Performance Stealth Muffler.

I've been looking into those. Which model did you use? (pipe diameter, length.) Any sound clips or video? Very few examples of "Stealth" I've found, plenty for "Mach" and a few "Quantum."

Wow, the STL 18's are smaller than OE (volume-wise, height and width are less,) but still quiet as stock, even with headers?

Thanks. That helps a lot.

Judging volume by online videos is difficult because of most consumer devices (including phones) using automatic gain compensation (turning down the recording volume when the actual sound gets louder) but the fact that you can still hear ambient road noise and belt whine over your exhaust is a pretty good indicator of relative quietness.

When you're watching an exhaust video, and you can hear belt whine at idle but it disappears when they rev, then fades back in as the engine settles back down to idle, it means the "rev" was louder in real life than it sounds in the video.

"Quiet as stock" is also a relative term, but your video doesn't seem to be much louder than my GP was when I got it. I still don't think 3800's sound good (even if I like the engine overall,) but for a "quiet performance muffler," I'd call that a win.