Quiet, mellow mufflers?
 

I need some help from those more experienced then me on muffler selection. This is for my '56 Chev pickup with a hot cam LS-3 and a 6L80E. I bought it with a horrendously noisy exhaust system. It had terrible harmonics, and it was torture to sit in the truck at idle.
I just had the entire system replaced with mandrel bent 2-1/2" stainless pipes, H-pipe, and Magnaflow 18" long mufflers. As the truck has a C-4 IRS suspension, there is no reasonable way to exit it at the rear. The exit is out the sides, ahead of the rear tires. The old system had turn downs, but it was blowing dirt all over the rear wheels, so the new system has straight out square tips.
I "auditioned" the Magnaflows, but the shop was in a metal high-roof building and what I thought I heard inside is not what I ended up with.
The new system is at least as loud as the old system, and with any reasonable throttle, it is way noisier. The harmonics issue is gone, but I don't think I can live with this. I have the Camaro with Flowmasters as the in-your-face vehicle, this one needs to be a quieter, mellower hot rod.
So I am looking for recommendations for a QUIET muffler. Performance is a secondary consideration.
Thanks in advance for sharing your experience!

Bill

I've only tried Magnaflow on my daily Yukon. Their cat-back system. A little too much sound for me on a daily and had a terrible highway drone. Flowmaster has several different styles of mufflers and they are rated by sound, I swapped just the muffler on my Magna system over to a flowmaster an have been very pleased... something I noticed though, usually the quieter the muffler, the bigger the muffler... pay attention to the sizes.


Jef-

Thanks, Jef. Do you know which model Flowmasters?

I've tried several types of mufflers and the one I felt was the best for power/ flow and mellow quiet cruising was the Dynomax turbos. They're decently deep toned and quiet when cruising and come alive fairly well when you lay into it. As with other turbos they have internal flow direction changes but they have bends inside the muffler that direct and keep the flow moving smoothly instead of just dumping into a chamber and then moving through another tube, if that makes sense.

I grew up in the 80s and have always loved the sound of Flowmasters, but every vehicle I had them on from a street strip Nova to my 76 Suburban to my G-body wagon the drone was a little annoying. Their larger truck mufflers are said to cut down on that drone.

50 series Delta Flow is what I used on my Yukon...

You could try adding resonators up stream of the mufflers if you have room.

Borla XS. Run your pipe/pipes (mine is 3" single) under the C4 pumpkin. Mount muffler(s) at end of vehicle, not under the middle. This is the best muffler I have ever had in my 20+ years of doing stupid hotrod things (and I am so old that I now hate loud exhaust).

Is it an 18" case length or 18" overall? The biggest they make is 4x9, 24" overall (18" case) and is fairly quiet. I installed a pair on an LSX 454 and they was too quiet

Have you researched side branch resonator / Helmholtz chambers / "J" pipes? It may be a less expensive way to "tune" your exhaust.

http://penn.freeservers.com/jeep/wj/qfrexhaust/

https://ls1tech.com/forums/cadillac-...ltz-tubes.html

I know it's not a muffler, but it may be worth looking into.

Also, you may want to look at:



:cheers:

I ran the Borla XS and it was pretty quiet..it also depends on muffler size.

I ran Billy Boats on my Mustang that were 20" long and even with full 3" exhaust and a fairly hot motor it was quiet compared to most to run 90DB at Laguna.