Got a customer wanting a really quiet exhaust on a truck i am fixing to start doing a turbo build for. S476 on a 4.8.

Ive done 4" from turbo to tail pipe with a large 36" diesel muffler and a 18" resonator and it was kinda quiet but had a drone.

I want to try and do a 4" Inlet/dual 3" outlet Y, then a couple really big 3" mufflers. Hoping to let it flow good and still be quiet.

Ive got a Dynomax 17235 on my 2500HD without Cats and its very quiet, almost stock but a tad deeper note. Its the largest Dynomax they make at 24" or 30" body length.

Never done a y pipe on a turbo setup but never tried to keep one this quiet.

Any ideas?

 

Just make the entire thing outta muffler

 

Few more pounds of boost to offset the extra weight?

 

I had to make two different drone eliminating tubes to get rid of the drone on my quad muffler 4" exhaust.

 

Made a huge difference.

 

I'm running 2 vibrant resonators. They freakin work...

 

I used their largest resonator on my 4" exhaust with a AP Exhaust 36" diesel muffler and it was still kinda loud. But thinking back i think that was because of the turn down at the bumper vs a tail pipe..
Ill have to give it a try and report back haha

 

This also worked really well on mine to knock down the sound significantly.

 

I have been thru several iterations of the 4" exhaust on my reg cab and they have all fallen short in some area. I feel like the original 36" magnaflow was the best at sound attenuation until all the packing blew out of the muffler. Since then I have tried several other mufflers and 1/4 wave resonators. They all seem to be loud or drone in one RPM or another. I think a 4" exhaust on a gas motor is going to be inherently loud at lower exhaust volumes due to the size of the piping and velocity of the exhaust. I actually want to redo mine to dual 3" with an X for more muffler volume per exhaust volume to tone it down. The 4" downpipe into 2-3" idea has some merit, imo, but will have to be mindful of the Y-merge used to ensure it flows well in the opposite direction.

 

Ok just realized that the turbo kit he got connects to the factory exhaust.. So going to try a 3" to dual 2.5" or 3" to open it up some.
My old KB Racing kit had 4" off the turbo to past the transmission and i ran 4" from there out. I didnt think to check this Huron kit till now.