I have a 2017 RAM 2500 6.4 HEMI. I wanted to coax more power and a performance sound out of it so I had a custom exhaust system built for it (a CAI system from K&N is sitting in my garage waiting for the next phase of my bolt on quest for maximizing the HEMI's power). The OEM pipe front to back is 3.5" and I couldn't see getting rid of virtually new and good quality OEM piping so I asked for the muffler to be replaced with a MagnaFlow performance muffler, remove the OEM resonator and put a custom 2 outlet slant cut stainless steel tip on it. I couldn't do a dual exhaust exit because of the tight surrounds of the coil sprung rear end so I only have the one pipe, front to back. To be sure I still had 3.5" from front to back the shop ordered up mandrel bent pipe with the muffler (stainless steel as well) and modified the tip I supplied to make sure there was nothing less than 3.5" anywhere in the system. This guy has done work for me before and does great work at very reasonable prices so I know he knows what he is doing (I got a custom built system for less than half the cost of a bolt on store bought system). I love the sound and noticeable performance but it seems louder at freeway speeds than I remember from other similar systems I have had; it almost has a drone to it). So all this being said to set the stage, I am thinking it is noisier because of the large 3.5" pipe, the performance flow thru 3.5" muffler and "no resonator", which I understand but wasn't expect to be that much difference from what I have experienced in the past.

I have a theoretical solution to tame things down some and that is the real crux of my question: Will exhaust heat wrap on the muffler and a short distance in front of and aft of the muffler contain some of the noise that may be emitting through the case of the muffler and pipe closest to the muffler? Since this is right under the cab I thought if there could be some containment that it would reduce the noise (heat is not the issue) from radiating into the cab (which I suspect is happening, at least somewhat) and quiet things down some in the cab as well as reduce the suspected droning affect. It kind of makes sense to me so does anyone out there in MOPAR land have any experience or an opinion on this?

I welcome your response, advice and input. Thanks in advance for your responses.

I have not used header wrap, but I have seen headers that have rusted to peices because of it getting wet and holding water against the metal.

That thought about rust has crossed my mind but we are talking about stainless steel and I think I would be OK regarding any rust issues. There are no leaks in the system and the drone and/or DB's seem to be radiating up from underneath. I can't help but think that the muffler is emitting some of its noise from around the body of the muffler itself. I am going to give it some more thought and get back to my exhaust guy to ask what he thinks as well. I was hoping someone here may have had similar issues and tried something like this to counter act excess unwanted noise or drone. I have had similar systems before so I know to expect noise but this one is a little more than I expected.

I would expect a wrap to help with high-frequency sound - like "ringing" - but not the lower-frequency "booming" or droning; that was probably the resonator's job.
I've wrapped a short length of header primary tube near the starter before, and didn't notice any difference in sound, though that comparison may not apply here.
The wrap is relatively cheap from an auto parts store, so you could try doing some and report back.

This, but then in the OP's case, there is likely little HF emitting thru the muffler case or tubing in the first place.

And the wrap "trapping water" is a non issue, unless one drives thru standing water when cold, and then immediately parks the car. The wrap basically overheats steel tubing, causes it to oxidize at the newly elevated temps, and also cyclically heat fatigues the metal, until it crumbles.

and something to remember about stainless is the grade quality. the common "4series" stainless will take less abuse than the "3series". what grade stainless did you use in your installation ?

The factory mufflers are usually quite "big" and long.How long is the replacement muffler compared to the stocker?Couple that with no resonator and you may have your answer.Stick a 3.5" resonator/bullet muffler somewhere and see how it reacts.

Those magnaflow mufflers are LOUD. I'm running a 13749 on a 92 318 and a 88 5.9 and the 92 gets me unwanted attention on a 3 inch single exhaust with a eastern catalytic converter and full length pipes.

Comparatively the equivalent walker dynomax 3 inch RV muffler was much better and quieter but was aluminized instead.

I would start by reconsidering your muffler choice.

Thanks for the replies. I have decided against the wrap. I did some research and discovered that a J pipe looks to be my best bet. I Googled "getting rid of exhaust drone" and got some surprising (to me) results addressing exactly what I am dealing with. I went back to my exhaust guy and he is going to install a J pipe just aft of my axle and forward of the exhaust tip (that is where I have the most room). Very interesting information and I would recommend anyone with a drone issue, regardless of what kind of system you are using, to check it out. Almost everyone that had something to say about J pipes or any kind of resonator pipe installed into their system reported that the pipe eliminated all or most of the drone. I hope to get this done next week and will report my results here after it is done.

UPDATE: it took some time but I finally got rid of the drone/resonance in the exhaust system. It was as simple as adding a J pipe. My exhaust guy had custom made a 29 5/8" J pipe and tapped into the exhaust about 6" behind the muffler. He curved it slightly up and forward and then reverse curved it up over the exhaust pipe and towards the rear axle. He built a slip joint to tune 2" forward or 2" rearward from the 29 5/8" starting point. The 29 5/8" starting point worked great after the test drive so he tack welded (he welds everything, doesn't like depending only on clamps)the band clamp he used at the joint. The only drone I hear now is now very slight (is more the load on the engine and only when there is a load on the engine, not when cruising at steady speed) with the Magnaflow muffler, much quieter and sounding more like the flow through muffler that it is and not drone. Very quiet at cruise and did the trick. No need to wrap this or bullet that, J pipe was the way to go.

I'm kind of confused what a J pipe looks like. The only J bends I have seen come with an unwelded set of headers. Did you take any pics?

Modern Challenger J pipe exhaust

Challenger RT J pipe exhaust

It just provides more volume and stops? Freaky...

This is really interesting. Wondering if sound outside is affected and if the diameter of pipe has an effect. Also wonder if placement is critical.

The "J Pipe" talked about in the above posts is more correctly called a "Resonant Acoustic Stub" and has been discussed here on Moparts several times in the past. It does not have to be shaped like a J. It does have to be a specific length to cancel a specific tone. If the temperature of the exhaust gas changes, so does the frequency of the sound tone cancelled.

This same scientific principle is used to quickly measure the static compression ratio of NASCAR engine cylinders during inspections.

A "slide whistle" works this way too.

https://www.amazon.com/American-Slide-Wh...s=slide+whistle

With a given pipe thickness a 3 1/2" pipe will emit more noise because it has more surface area and a greater circumferential bend radius, so it is less stiff circumferential and, hence will vibrate more with a give exhaust impulse energy.

The j pipe is essentially a cheap version of a resonator, so I'm not sure what you gained by eliminating the resonator.

IMO, for a GAS 5.7L Hemi engine, 3.5" diameter exhaust is too big & you will lose velocity through the system - bottom-end & midrange will suffer. Single 3" would have been a better diameter. As far as the ol J-hook sound trap, a good resonator would have solved the resonance issue.

I do not have pics. Also, the OEM resonator was large, heavy and took up too much real estate for me to have the custom exhaust I was looking for. As far a engine size, I did state that it is a 6.4 and the 3.5" piping is OEM. If the factory put it there then I would expect it is sized right and be the most efficient for the vehicle it is on, which I believe I also stated it is a RAM 2500 HD. The exhaust system and the addition of a CAI system gave my truck about 2.5 more MPG and a noticeable seat of the pants feel in additional power. I also notice less shifting with the trans and it definitely shows its oats pulling a 5th wheel. I knew I was going to do the exhaust when I bought the truck. I priced a cat back system and the prices were upwards of $1,000 for quality systems. I had my entire system custom done for $600. Used as much of the OEM pipe as possible (no reason not to) and swapped out the muffler. The bulk of the work was done from the muffler back, all custom. The guy welds everything and does exceptional work. The J pipe is not a cheap bandaid to a built in resonance problem, it is a scientific fix the factory recognized with their addition of resonators, except, they seem to want to use the bulky overweight real estate stealing factory ones. All this being said, I am not an expert but have found out what works for me. I don't need anyone telling me about how J pipes are a cheap fix, should have kept the factory set up, if I don't like noise don't put this or that muffler on. Everyone has their own opinion and that is great but this worked for me and I thought I would share it with the MOPAR community.

J Pipes, resonators, X connectors and H Pipes are all equally scientific methods for modifying sounds from an engine.

I wonder if for diagnostic purposes whether a temporary adjustable length J Pipe could be made that could just be pressed on to the tailpipe exit and supported by the bumper?