Quiet you say? I know, most people want something louder, but I've got a 3.4, and 'loud' just doesn't go well with it.

Currently my Dynomax 2.5 single in, dual out muffler is getting louder, and my fuel economy is getting worse. It used to sound ok with the 2.8, stock manifolds, and 2.5 cat back, but since I put in the 3.4 with headers several years ago, it's always been a bit too loud.

(Is the sole cause of my increasingly bad mileage due to the muffler going bad? I don't know, as there's a ton of other things i still need to check)

I'm thinking about getting another 2.5 muffler (just to match up with the 2.5 I-pipe, and putting 2.25 outlets on it (it is a dual outlet afterall).

I don't know anymore what series my current muffler is. I put it on back in 02.

I'm also thinking about putting the stock exhaust manifolds back on. My mileage used to be great with the old 2.8, but never has been quite the same with the headers and 3.4, and there's only one way to see for sure.

Most of my driving hovers around 1500 to 2000 rpm, and I've always been wondering if my current exhaust's tuned rpm range is far from that.

 

Have you considered adding a resonator inline with your muffler. Last V6 exhaust I built had 2 resonators and a borla straight through muffler and it sounds great when I step on it and it is very quiet when I am cruising.

My experience with dynomax is their mufflers tend to get louder over time and usually rather quickly.

 

Somebody did mention adding a glasspack into the system. I'd have to look closely at the diameter of them and how much ground clearance I'd lose under the middle of the car, as that's the only straight stretch of pipe there is that I can think of. I'll check out resonators and see where I could fit one.

Current muffler has probably 80 - 100k miles on it.

 

Most of them are about 3.5inch in diameter and can be had for about 20 bucks for a cheap one. I would go for the perforated one over a louvered because they reduce flow less

Here is the last exhaust I made with 2 silverline resonators

 

Let's see these headers... I've always installed headers and smiled at my 2-3 mpg increase.

 

I should have ran the 3.4 for awhile with stock manifolds, then installed the headers to see what the difference would have been. I stuck these on the engine and installed it. It could be that my stock ECM doesn't like the extra air from my intake I made, combined with the 3.4 and it's bigger injectors vs the 2.8 and it's injectors, and the larger exhaust system too. Maybe I'll leave the headers on for now and just get a new muffler, and if it's still got that ***** sound, I'll try to fit a resonator or glasspack in there somewhere. Or go back to a 2.25 inch I-pipe.

These are made by Pacesetter.

 

Your muffler "going bad" is just breaking in. And that would not decrease MPG. 9 out of 10 times its the driver hitting the gas pedal, haha.

But I agree. If you wan't to take some of the high pitch raspy sound out, add a resonator (glasspack) and that will take some sound away.

 

[QUOTE=SDTransAM;5117123] 9 out of 10 times its the driver hitting the gas pedal, haha.QUOTE]

I've actually been lighter on the gas pedal lately because of how obnoxiously loud it is when accelerating.

 

I have a original exhaust 2.5 pipe on my 89 other then the new Cat I just replaced. It had the original one on it from 89, People would say nice sounding car. But since I changed the Cat it sounds like a rice burner. Don't get it. Would like some input.

 

I like Spintech. Not loud untill you floor it and it actually sounds good not obnoxious.