Quietest 3” mufflers....GO!
 

I want to quiet my Lemans down, you know to help with the surprise factor. I have hooker supercomp headers, 3” Pypes x pipe with cut outs, and right now I have a set of 18” case AP exhaust Goerlich X-celerators. I want to make it as quiet as possible without compromising street performance too much; I always have the cut outs if it gets serious.
In Jim Hands book he shows the Goerich x-celerators as the highest flowing 3” and the dyno max welded ultra flows as the highest flowing 2.5”. I’m thinking of going to a 3” 24” case dyno max welded ultra flows. Thoughts? Thanks in advance!

Here is my recent experience with Ultraflows: 600hp motor with 3" X pipe, long case 3" ultraflows and 2.5" tail pipes... good sound yet surprisingly quiet until you went full throttle.

With same motor, I now have 3" all the way through with H pipe and 14" ultraflows. Not obnoxious by any means, but definitely louder than the first combo above.

I prefer #1, as I am sure my neighbors did as well. but large case ultraflows would not fit in the first gen, and nobody offered a kit with 3" mid and 2.5" tail pipe.



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I ran the bigger case 3" Xcelerators on both my 67 Firebird and my 69 Falcon wagon. I think the case was about 22", I actually notched the case and welded-in patches to get a better fit on the 'bird - Tom Hand was supervising via e-mail on that project. Both cars were surprisingly quiet. The Firebird ran 11.2's and the Falcon was a bit quicker and several hundred pounds heavier.

Walker Super Turbos

I've run both, the Xcelerators and the Super Turbos, and the Super Turbos are a notch quieter, especially at WOT. Run the largest case you can, the shorter ones are louder.

Can't remember if it's the 20"s or the 23s that are on the 442, but it's pretty dang quiet. Perfect for that car. No drone at any RPM. The Xcelerators have no drone either. (I run X pipes on all cars)

I prefer the goerich's, the crackle they have is something I really like. Very unique sound, haven't heard another muffler that sounds like them.

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Another pleased 3" Ultraflow person. On the 78 TA and now on the 79 Camaro/IA . Camaro is a little louder as I kept 3.5 X all the way the the mufflers,whereas the TA reduced right past the collectors to 3" and a 3" X.

Loosely related to this thread-
The single Flowmaster 40-series (3.5" in/out) on The Bandit Suburban (455HO) is very loud. I can't find an appropriately quieter 3.5", so I'm considering a 3" Flowmaster 50-series. Anybody ever used one?

I ran 40 series with dumps. I could not drive the car. It was so loud with a drone. It gave me a headache instantly.



With tailpipes it was manageable.

Ready to remove my single chamber 3" Vibrant 1142. I'm hearing the Walker 21357 are the quietest performance dual chambers. Anyone have any experience with these?

the 24" ultra flows will be slightly quieter because of the size of the case, not by design. The Xlerators, Ultra Flows, Pypes Race Pro and Magnaflow all use the same design and therefore the only thing that will change the sound is the size. If you REALLY want to get quieter, then go with the dynomax Super Turbo if it's still available in 3". Significantly quieter than all of the above.

If you go with the 3" Super Turbo, get the larger size (5.5" x 11")case: it keeps the full 3" in the internal tubes. The smaller case (4.25" x 9.75")Super turbos neck down internally to 2.5".

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I've got the old Torque-Tech 3" system with the Flowmaster Delta 50's on my blue '67 GTO. Mellow at idle and cruise with no drone. Things change when I have my foot in it and it becomes a cop magnet at that point. Iron heads, Dougs D-port headers, and an H-pipe with no cutouts.

Cell phone video so sound level is clipped somewhat. Video from club dyno day in 2018: Blue Goat on Dyno

I've got the big 3" Super Turbos in my '66 GTO (and Doug's round-ports) but the car was still way too loud for me. I then installed those little "resonator"-looking things: http://www.dynomax.com/mufflers/race...und-24405.html and those made just enough difference to make it tolerable.

Also, just looked at the Dynomax website and it looks like they no longer have the long-case 3" offset/offset that's the correct configuration for '64-'72 A-bodies... might want to call them to verify.

I like the Dynomax Super Turbos but lately I've been having issues with parts coming loose inside them and them making noises..

Glad to hear Goerlich is still in the muffler business, I see muffler ads from them in Hot Rod magazines from the fifties.. Here's one for a 58 Pontiac.

I picked these up from Walker, they are the longest biggest 2-1/2" muffler I could find. I'm going to run them without tailpipes on my 69 el Camino with 454. Check the Walker catalog under 3" truck mufflers, you might find the perfect one..

Did you put them in the tailpipes or in front of the mufflers? I’ve been thinking of trying those even though the long case Ultraflow’s and 3” pipes are tolerable.

In the tailpipes where the stock resonators were.