I’ve pretty much finished the build of my Jeep that pertains to anything off-road. Now my problem is that I want to try to make it better for daily driving and a bit more comfortable. The biggest issue at hand is that it’s absolutely loud inside. I do have a borla exhaust which is far from quiet and there’s little to no sound deadening inside the cabin or under the hood.

I took some decibel readings today with an iPhone app. It may not be the most accurate (not sure) but as long as the readings are consistently inaccurate, then I’ll have a good comparison of before and after.

As of right now at an idle, the readings inside the cabin at the driver seat are between 77-80 db. When accelerating up to about 75 mph and normal driving I’m at about 95-105 db.

Im going to start with tearing the interior apart and laying down some 80mil butyl sound deadening. The muffler is going to get replaced with a quiet one as well.

Future plans are to remove the top and use the same 80mil sound deadening and then a cover king head liner. I’ll do this when the weather warms up a bit.

I’ll keep this thread updated with what things make what differences in sound measurements inside the cab.

 

The problem with a lot of these aftermarket exhausts is them not using a resonator. It makes a big difference. I previously had the Magnaflow off road pro exhaust and it was very loud inside the cabin and droned heavily on the interstate. It sounded good outside but became obnoxious inside. I sold that and went with the AFE rock basher exhaust and it is significantly quiter on the inside while still sounds good on the outside. Both systems have no resonator and dump before the axle. The sound deadening will definitely help and just having carpet and mats lower the noise considerably.

 

My exhaust dumps just beyond the axle but you’re correct that there isn’t a resonator.

I can add one but I’d rather just put a quiet muffler on it.

 

I bought this one to let the stock 2.5" exhaust breathe better with the V8. 2016 Chev with my engine used a 2.5" exhaust so mostof mine was stock except for the crossover system. Noise on hiway is negligible and nice rumble around town.

Dynomax 53804 - Dynomax Super Turbo Muffler (partsengine.ca)

 

Driving with 95-105 db noise is really high! Having worked a bit in hearing protection required areas, I looked this up: >85 db is hearing protection required (based on 8 hours) and 100 db is only 15 minutes max without hearing protection. If it's really 100db, a conversation would be quite hard to have.

I've had this RR muffler for years. Decent ground clearance and the sound is enough to easily hear when to shift, and still have normal conversation or listen to the radio. I think the exhaust exiting aft of the rear axle is best for sound and health. The only insulation I've added is to the hardtop, but that was for temperature.

Suggest changing out the muffler before adding sound dampening, it may not be necessary. The rubber exhaust hangers may be hard and transmitting vibes/sound, and new ones are much easier to install when replacing the muffler.

Pic from about 7 years ago after install... The angle of the camera makes the outlet look lower than it actually is.

 

Thanks for the input guys. After briefly looking at resonators, I think I’m going to rule that out. They don’t seem to do much as far as reducing overall volume. As far as exhausts are concerned, I don’t have a factory exhaust and my muffler is currently positioned adjacent to my transfer case. I need to find one with a 2.5” in/out and with a somewhat small circumference. I have looked at the Walker quiet flow:

https://www.amazon.com/Walker-21856-...d_i=B000RUDJB0

Theyre a cheaper muffler but the reviews I’ve seen on YouTube makes me believe they’re a pretty quiet muffler. I may just let an exhaust shop take the Jeep and just tell them to make it quiet.

 

With a non-factory exhaust setup, a shop sounds like a good plan. A decent muffler shop will have a pretty good idea of what the sound will be, as well as what fits in the available space.