ddestruel

alright i've tried several combinations

in my sig ive got an 03 305/555 with a ATS manifold and a S300 HTB2 62/12 so realize my engine tone and note is going to be louder than it was with a stock turbo. i have 4" down exhaust. I am currently running the 5" in/out 51" donaldson muffler with 4" to 5" reducers as far back as i can get it before the axle. 3 rubber issolator mounts at the muffler, nothing at the transmission. I previously ran a 24" muffler and later a 36" muffler neither of which could get rid of the horrendus drone that occurs while towing up grades with big loads. so i stepped up to the donaldson, which the donaldson lowered my outside noise but actually amplified the interior drone. i mean loud like don't bother talking to your passenger because they wont be able to hear you....type loud

Ive thought about putting the 24" muffler back in and installing it under the passengers feet as some sort of resonator but i have been told location of the muffler in the system dictates tone and potentially drone. supposedly the further back the better.

current issue is from 1700-2100 rpm i'm open to some suggestions. my buddy's 05 with straight pipe and just the CAT is quieter than my 03. seriously this is driving me nutz

do i need more isolator mounts? would the extra 24" muffler help? should i install a mount at hte bellhousing? should i wrap and clamp the exhaust pipe in the front to reduce resonation?

dogger

I'm kind of in the same boat as you (see my signature) and I tow too much to put up with the drone. Some people would say I took a step backwards but I installed a factory 05 Dodge muffler onto my MRBP 4 inch exhaust so I have a 4" in and out muffler. Although it is not perfect it definitely reduced the drone inside the cab, an it has to breath better than the 3 1/2" in 4" out stock setup. I had to shorten up the hanger on the aftermarket tailpipe (rebend) some but it looks good. The 05 muffler will fit the stock rubber muffler hangers. Good luck!

L8r,.........dogger

lniemeyer2

Had a guy tell me to loosen all the clamps, start and put the vehicle in gear (fwd/rvrs), shut it off and retighten. For some reason it will get a little bind and cause drone. This theory worked for me although I did have to get the dremel out and grind off the spot welds from the exhaust shop. The exhaust shifted maybe an 1/8 inch or so after doing what is listed above.

C Schomer

My 4" exh/51" nelson was really quiet til I changed the turbo and I got more noise and the drone. I put a 4" glasspack as far forward as I could get it and it stopped all the drone and made it a little quieter - I still have the nelson, too. It's acceptable now for talking and radio. Craig

rip 112

Have you tried putting a resonator in front of the Donaldson?

Rednax

Had an AEROTURBINE 4040 on mine when I bought it. A kiddy sound, and terrible drone when towing. Used it as resonator and added a ROKKTECH "Silent Might" muffler. Moved the Aero forward to act as resonator. As quiet -- or quieter -- than stock, and at low rpm highway cruising as quiet as many cars.

j-fox

A long time ago someone found that a length of angle iron clamped to the exhaust pipe forward of the muffler stopped the drone. Try it.

dogger

What size angle iron and how long? Do you just use some large diameter hose clamps?

annabelle

I was told(by Roktech)they no longer make the Silent Might.

kw5.9

if I turn my radio up or have my window down my drone goes away and it didnt cost me anything

ddestruel

i wish it was that easy. can't stick 4 guys in the cab and not have a conversation for 10 minutes while climbing a grade or on donner summit its 45 minutes to 1 hour of solid drone with the trailer. nothing like taking your boss and your banker up camping and on a jeep trip only to not be able to talk to them because the cab of your truck is reverbarating like a blender on steroids

Pull Dog

When I bought my 05 it had a 5 inch system with a muffler that was actually just an open chamber. The noise was unbearable especially when towing. Anyone sitting in the back seat had a horrible vibration in their seat. I took it off, put the OEM stock 4inch system back on and now it runs as good as before, I have no noticeable decrease in MPG or power. I checked the mpg on several tankfulls before I replaced it to see if I was actually hurting myself in fuel economy. I still get 18 local and 21 trip while not towing. Whoever had the truck before me wasted a lot of money on a 5 inch system and caused me a lot of expense to replace it.

Pooter

What really helped with my drone on the highway was adding sound deadener, everywhere. I have a stock downpipe to 5" straight all the way out and its almost as quiet as a stock truck with the windows up now...
Even if you dont want to line the entire cab, just doing the roof and back of the cab will help out quite a bit.

AlCorr

This is one I really want to hear about!

What size angle iron and how long? Do you just use some large diameter hose clamps?

Totallyrad

If I'm correctly remembering the one you're talking about, I think they only used radiator clamps on 3/4 or 1" angle. The clamps may have been about 2' apart.


On edit: I did a little searching but could not find the thread with the pics but... I looked at several threads and the size of the angle iron used ranged from 3/4x3/4 to 2.5x2.5. Some guys just clamped a piece the length of the straight pipe in front of the muffler while most to another approach. They would take a piece of angle about 2' long and clamp it on the straight pipe ahead of the muffler like the others. Then they would move it around until they isolated the spot that reduced the drone the most. Then some would weld it in place.