I bought my 2003 dmax used. The previous ower installed a 4" exhaust. It sounds and performs great. However, when I am pulling my RV the drone is a little high. I would like to decrease the drone to the level I have when I am not pulling the RV. The sound, or drone, is similar to when you are driving past a concrete barrier and the exhaust is bouncing back to the truck. I think the sound is bouncing off of the RV. The end of the muffler has a large tip on it. It looks to be about 6 inches. Would removing the 6" tip make the drone louder or quieter? Would turning the end of the exhaust up, down, or forward help? Again, I am looking to just lower the drone level about 25% when I am pulling my RV.

Thanks in advance,

Getting rid of the tip is it is 6" will quiet it some, also playing with the tip length will help some. Does your truck have a cat? If not you can add a small resonator in the front pipe to reduce the noise level.

Look to see if he removed the muffler, also a resonator might help.

I looked under the truck and did not see a Cat, unless it is tucked up next to the tranny. The muffler looks to be about 6 inches in diameter and about 18 inches long. It looks like a bullydog exhaust. There is a long run of straight pipes so an additional resonator might help. The exhaust is assembled with the sheet steel type clamps so it should be easy to retrofit. Where do i get a resonator for a bullydog exhaust?

You can get a resonator from MBRP (thru DPP), Air Flow Systems, and Magnoflow, at least that is what I found so far (undecided so far). They'll run between $80 -$120. They are about the same size as a straight-thru muffler. The there is also some heavier duty, bigger, straight-thru muffers from Donaldson. Lets us know what you end up with and how it installed and worked for you. I'll do the same.

This is what is in my exhaust pipe. At least this is what it looks like from the outside. Maybe I already have a resonator and not a muffler. What does a muffler look like? What does a resonator look like? Whats the difference?

http://www.dieselperformanceparts.com/images/1886.jpg

this is a reversible muffler.. one direction is louder while reversing it with the louvers facing the front, will quieten it. Also, if you had a cat you would know it.. they are too big to miss.

as mentioned already, you can get a resonator tip or a resonator up front.
first see if the muffler can just be reversed.

remember, louvers facing the rear is loud, louvers facing the front is quieter.


This is what is in my exhaust pipe. At least this is what it looks like from the outside. Maybe I already have a resonator and not a muffler. What does a muffler look like? What does a resonator look like? Whats the difference?

Do the resonator. The 1600-1900 RPM drone will be eliminated. For lower EGTs and quieter ride, the best of both worlds is the combination of flow through type muffler and a resonator.

tcbusch,
The guys are right you need an extra muffler/resonator (basically the same thing) we have a shortie one (18 inches overall) that does the job for most folks. They are available in aluminized and stainless. Call us if you have any questions etc.

Mark @ DPPI