Flowmaster 40 Deltas too LOUD! Please suggest...

[76LongBox]

I admittedly didn't read all of the replies above, but I will tell you that last year when I was working on my interior and had all of the carpet and jute out of it, my truck was LOUD on the inside.  I still had the headliner, but nothing in the floor, and it was annoying to say the least.  I didn't like driving it at all like that.  I had the carpet put back with new jute and also some asphalt style sound-deadening mat, and it made a world of difference. It had been so long since I had ripped out the original carpet, but I really believe the sound-deadening mat made a huge difference even from what it was before I ripped out the original carpet.

I can only imagine how loud your truck is with no carpet and no headliner either....

[Rich84]

The 40's drone like crazy..I added resonators right in front of the mufflers. Now it drones much less, and should be tolerable if you put some sound deadener and a carpet in.

[Jim_Hensley]

Flowmasters are about the worst flowing muffler you could install ..Switch out to some Ultraflos or even cheap ass $20 turbo mufflers and enjoy better flow and better sound and no drone.

[Greybeard]

Can't agree with the no-drone assessment of cheap turbo mufflers. That's all I've put on a truck. They drone like the dickens. They always sound good though.

I have a suspicion that at least some of the droning is caused by too big of exhaust pipes for the engine. The sound pulses have too much opportunity to pass through the pipe wall due to slow flow instead of being forced through and out of the pipe by the high velocity gasses. Just a thought. Just listen to a diesel for an instant to see what I mean. The sound is much hollower. That hollow sound is due to slow gasses. Droning, to me, is hollow sounding. 2+2= maybe?   

[Funracer]

Exactly the same problem with my 85 C10.  Google "J pipes" for lots of good info and pics.  My muffler shop put one on each side and
it cut the drone by 70 %. 

[Greybeard]

I like this. Never heard of this system before but it makes sense.

[a.graham52]

That thumping you mention... how is the exhaust hung? Is it hung to the frame or the body/cab? I used them cheep rubber strap hangers and I can tell my resonance is certainly ly transferring through them. Best thing Iv found is rubber hangers u find on new gm trucks. Just a thick rubber loop with two holes in them. U can see them at the end of the tailpipe behind the spring, so next time u see a 2000+ gm truck, take a peek.