Vortec350ss

iTrader: (20)

something like this sounds like your only option if you can't go before the rear tire. I always thought exhaust through the bed was bad ***... not sure I could bring myself to actually do it though lol. Spoolin's truck nailed this.

SCOTT_A

iTrader: (1)

Have you read the sticky at the top of this forum about building a Helmholtz resonator? It works with a dead ended tube off the side of your exhaust for the purpose of canceling specific frequencys of sound.

GMCtrk

iTrader: (27)

Haven't taken a look at it yet, but my problem as has been pointed out in this thread, is the fact that exhaust is exiting under the bed. I've been doing a lot of brainstorming....from turndowns, to flexible exhaust tubing, to different mufflers, to oval exhaust tubing, etc. I'll update when I come to a solution. Whatever it is, I want to maintain the exhaust area provided by 4" tubing.

Atomic

iTrader: (42)

That's not your problem its the length of the pipe. Mine exits under the bed and its fine.

GMCtrk

iTrader: (27)

Is this what you're currently running?

Atomic

iTrader: (42)

Yes. And before you say you cant go over the axle like I did, keep in mind even though mine is still pointed at the ground under the bed it is so much quieter now than when it was just pointed straight back. Also the area of a 4" pipe is about 12.5 sq inches, and dual 3" is about 14.14 sq inches.

GMCtrk

iTrader: (27)

Thats the point, theres more to it than the length of pipe. Even the acoustic dynamics are different given the proximity of my bed to the ground versus yours. When I had the pipe over the axle and exiting by the spare tire there was no drone, it was great. In that picture of your setup mentally flip the axle over the leafs and imagine the clearance to the pipe.

Donaldson makes a plethora of big mufflers that Ive been checking out and they're cheap to boot. Im just not sure if i want to do a turndown right before the axle, id be weary of drone. Magnaflow has a 22" 4" inlet dual 3" out muffler but it has a 2.5" core. Dual 2.5s would be a roughly 27% decrease in area versus the 4", with dual 2.75" being pretty close and dual 3" exceeding a single 4" in area.

kbracing96

iTrader: (26)

If you wanna bring the truck up some time, maybe we can figure out something that will work. I've got TONS of scrap tubing and bends I'll give you and can fab something up for cheap! Maybe a 4" turn down/kickout and a resonator tube to kill the harmonics will be the ticket. Exhaust noise/drone is a HUGE petpeev of mine! Just let me know

lglowe

iTrader: (3)

On this topic what would y'all think of a dual 2.75s after my 4" magnaflow flow wise? The 30" magnaflow has a 3.5" core so that is the smallest point in my exhaust so would a a split to dual 2.75" pipes become the next restriction or would it even make a difference.

GMCtrk

iTrader: (27)

Its about 6% less area than 4" so I wouldnt even worry about.

BTW, i didnt know you had the 30" magnaflow, wonder how it compares to my 24". I would have gone with the 30" if it didnt neck down to 3.5"