Suggestions wanted for QUIET good flowing mufflers (sleeper build)?

[mopar 3 B]

"OP is building a sleeper. I doubt he cares about sound level INSIDE, he wants it quiet to the spectators/opponents OUTSIDE.
At least, that's the way I think of a sleeper."
Whatever

He had better forget any type of performance. Big block Mopar and quiet isn't happening. You can hide the sound by running it out back. But someone will still be hearing it with any kind of peddle.

 

[mopar 3 B]

What ever happened to the electronic muffler that was supposed to cancel sound?

 

[j-c-c-62]

Consider, normally ICE are considered in the 33% efficiency range for fuel consumed, that also normally means approx 1/3 is basically lost as heat, radiator, radiant, etc. 400 Hp at FW gives off the same amount energy in waste heat and the same third in acoustic energy out the exhaust. As a side note, 1 hp equals 745 watts. A typical quality stereo speaker is 10% efficient, meaning you would have to power the stereo speaker with 7,450 watts to get 1 acoustic hp out of it. Now multiply that by 400hp, and you can see the power levels needed to cancel exhaust levels fully. Think what a TF dragster acoustically emits, and it is nearly mind blowing. There are other ways to address the issue. Current one is to cause a useful tuned fixed resonance inside a muffler/exhaust that is counter to the frequencies the motor is exhausting, and that turns that energy into waste heat, and why mufflers get so hot, when they are achieving their intended goals, conservation of energy and all.

 

[Gary Gaz]

Had Flowmaster 40's to dame loud, went to Walker SoundFX for a 2.5" pipe part no is 18261, huge difference. they list the 2 1/4 inch on Rockauto. walker also do a quiter version called Quite-Flow I think it is.
more at this page

 

[68BabyBlue]

Accurate Exhaust standard or high flow Hemi mufflers are another possibility. They are available in 2-1/4 or 2-1/2”. Probably not the cheapest choice but another option.

I ran the factory originals on two of my cars, the reproductions on three of them. My favorite after 50 years, but not the cheapest.

 

[Some Car Guy]

I put super turbos and vibrant resonators on my GTX last year. Did the trick for quiet.

 

[451Mopar]

The DynoMax Super Turbos are known for their good flow, quiet sound, and reasonable cost. You can get them in 3" in/out also.
Most of the "quiet" mufflers only go up to a 2-1/2 In/Out size and I think are more restrictive.
I put Chrysler Imperial (large case size) 2-1/2" in/out Walker Quiet Flow SS (Stainless Steel) mufflers on the Coronet Convertible.
They still produce a decent rumble behind the 505" stroker, but a bit quieter than the Super Turbos.
Not sure the large case was the best option as it made fitting them a pain. I think they discontinued that model/case size anyhow.

 

[j-c-c-62]

What???

I heard you the second time.

 

[33 IMP]

What ever happened to the electronic muffler that was supposed to cancel sound?

I think Tesla's use those.......

 

[Ron H]

I ran the factory originals on two of my cars, the reproductions on three of them. My favorite after 50 years, but not the cheapest.

Ran FM 50’s for a while, nice sound, but just too loud, especially cruising. One’s definition of what is too loud and too quiet varies A LOT. Years ago a HS bud had a ’69 GTX stock exhaust and to me, was the coolest sounding, noticed how it would quiet down when cruising with an awesome tone. Not as quiet as some other rides I had with stock exhaust, a GTO and couple of E-bodies. The latter had large resonators, like my mother’s T-Bird and at the time thought they were too quiet…but 55-years ago. Some members here suggested the stock hemi mufflers from Accurate, yes not cheap, but wanted some assurance they would be quieter than what I had. I found they were a bit louder than I thought (have headers) but really like how they lower the volume cruising at any speed.

To each their own, of course, but trying to get it sounding like an Imperial I’d guess may rob performance and they are huge.
Just my 2-pennies.