Exhaust hum inside cab

[Dino]

I have a new TTI 2.5" exhaust with H-pipe and HP manifolds. Instead of the Dynomax Super Turbos thery come with, I installed the Ultra Flows. It sounded alright but it had an annoying deep hum inside at about 1800-2000 rpm, below and above that it's gone. Since this is cruising rpm it had to be fixed, so I did get the Super Turbos and it's the same issue. They actually sound better overall, but still that loud deep hum at cruising. Prior to this setup I had cheap headers with true duals, 2.25", and old Walker mufflers, and it didn't have this issue.
What may be the problem? The mufflers? The H-pipe? Any suggestion on what to try?

[John_Kunkel]

What you're experiencing is "drone" and it's caused by your combination of exhaust components. Changing one of the components in the system might eliminate the drone, might lessen the drone or might  make it worse.

From my personal experience, just about every aftermarket performance muffler will cause some drone...some will disagree and those who like "throaty" exhaust will just live with the drone.

https://thecarhow.com/how-to-eliminate-exhaust-drone/

[Dino]

Oh I thought drone would be more intense than this. Well I gotta change something. This is driving me nuts. Thanks!

[metallicareload99]

Main difference between what you have and I run is I have headers and an X-pipe with my TTI 2.5" exhaust system. I had a fairly bad drone with the super turbos but not the Ultra Flows. Another reason why I may not perceive a drone problem is cause my 440 wouldn't like to cruise below 2500 RPM whatsoever 

The easiest change for you might be to add resonators in the tail pipes like a factory Hemi car

[Kern Dog]

From my personal experience, just about every aftermarket performance muffler will cause some drone...some will disagree and those who like "throaty" exhaust will just live with the drone.

While I am not disagreeing, I somehow have not had any exhaust system exhibit the drone in any of my cars. If I'm interpreting it right, I'm thinking that drone is a low frequency, steady hum.
I have had a few cars with Flowmaster mufflers that sounded great to me but did reverberate when driving near sound walls, buildings and big rigs. By that I mean that I'd get a loud echo of the exhaust sounds bouncing off of nearby objects. It was a sharper sound and not a low tone by any means.
I drove to Los Angeles one year with 3.23 gears and the Flowmasters. None of the internal hum sound but as I stated, once another car was alongside me or a big rig, it really sucked.
Could that be considered a "drone" ?

[will]

I had that drone with my Pypes 2 1/2" and shorty headman hedders. I put some resonators on the exhaust, and it did get better. The muffler shop put them in front of the mufflers, which wasn't what I wanted. That was with the 383, the 440 has no drone. I went 3" with whatever ultra Flows it comes with.

[John_Kunkel]

Drone is the reason many factory systems have resonators...even the engineers can't predict what combinations will be drone free.

[Dino]

I'll add resonators behind the axle and see how that goes. Thanks!

[b5blue]

Cool! 

[Dino]

Tiny bit of an issue with this. The pipes are 2.5" OD. The resonators would have 2.5" ID, same as the exhaust tips. I was hoping to make just one cut in the pipe and connect the resonators directly to the tips. Besides connecting them with a short pipe on the inside, and a band clamp over the top, I'm not sure what else to do.
Any recommendations on which resonators to use?

[metallicareload99]

Are the tailpipes on Hemi cars 2.25" like 440 cars? Unfortunately I don't have any good ideas to offer

[Dino]

Yes they are. I'll figure it out. I just need to find a decent resonator.

[b5blue]

https://www.ebay.com/p/1628688437?iid=143778921773&fitmentTarget=Make:Dodge%7CModel:Charger&gQT=2

[Dino]

That's not cheap!

[b5blue]

Best price I could find! (For the real deal.)

[b5blue]

https://www.walkerexhaust.com/support/exhaust-101/what-does-a-resonator-do.html

[b5blue]

Walker 21610 may work, it's for old Caddy's.   

[doctor4766]

My old 69 had an annoying drone with a full 2.5" system
On advice of a knowledgeable friend, I had the pipes from the mufflers back re-made in 2.25" and the difference was amazing. 

[Dino]

I installed Dynomax bullet mufflers. Not all of the drone is gone, but there is a significant improvement. I also have the Ultra Flow mufflers I can try in place of the Super Turbos, and/or different resonators. I hope I don't need to buy new tailpipes and exhaust tips, but I will if all else fails.