Sound deadening for exhaust drone.

[20camaro12]

anyone know of a video that shows the before and after of an exhaust with j-pipes? I can't seem to find one.

[VR Baron]

Originally Posted by 20camaro12

anyone know of a video that shows the before and after of an exhaust with j-pipes? I can't seem to find one.

Not that I know of. At start up it made mine just a very, very little bit more quiet, thats it.

[LBV]

Originally Posted by CyberBri

I just dont wanna change my exhaust tone i dont see how changing flow will not alter sound...

The end of the j-pipes are welded at a 90 degree angle to the stock exhaust pipe (after a hole of appropriate size is drilled in the stock pipe). As such, the exhaust flow never enters the j-pipe (ok, maybe a bit at idle) but the sound waves do.

The correct length of j-pipe means the sound waves bounce off the end cap and head back and cancel the new waves coming in.

The sound will quiet down a minimal amount overall but the removal of the drone is where it shines.

[Kiowa88]

I know how you feel. I've been on a quest to kill my drone and in the process I think I've switched my exhaust 4-5 times now in the process. This is my current set-up and is absolutely drone free and is still pretty aggressive...

G6X3 Cam w/supporting engine mods
JBA Long tubes without cats down to 2.5"
Stock L99 resonator with the mufflers chopped off

The car still has the amazing idle, sounds like a pissed off banshee at WOT but has no drone. I used to drive around with ear plugs it was so bad. The worst range was from 1700-2000ish RPMs. I just drove from Savannah to Colombia this weekend with my girlfriend and we kept the volume around 12 and never had to shout to hear conversation.

I used to have the JBA 3" exhaust with their Hi-Flow cats and that baby droned like a mofo. I then tried the J-Pipe kit from Solo which helped a little but the drone was still there (not to knock on them at all, I think with the cam it just changed the required length more than which their kit could support).

I then cut off the JBA mufflers and had the Flowmaster Outlaws welded in their place. Still droned but not as bad. I tried adding some resonators which ended up just quieting the exhaust but the drone was still there.

But like I said, with the current set-up it is 100% drone free and I love the way it sounds. I'll get a video when I can. I can now hear myself think in the car again and I LOVE to go out driving again!

I don't know what killed the drone..either the reduction from 3" to 2.5" or the L99 resonator so I can't tell you for sure.

Hope this helps. And sorry for the long post!

[OPP]

Yesterday I had to put the back seat down to carry a big box and I noticed the exhaust noise and DRONE were increased inside the cabin. It was really bad and annoying. So the question is: How come sound deadening material is not going to help with drone if simply opening the back seat made it worse? I would deduct that a little more baffling in the trunk should reduce it at least a little.

[BigRed585Lbs]

No matter how much Dynomat you add, you'll still have the source of the drone. Just like a deaf man not hearing the noise doesn't mean it's not there. Best bet is to find a solution to eliminate the drone, not a band-aid to cover it up.

JMO

[Unobtainium]

Originally Posted by OPP

Yesterday I had to put the back seat down to carry a big box and I noticed the exhaust noise and DRONE were increased inside the cabin. It was really bad and annoying. So the question is: How come sound deadening material is not going to help with drone if simply opening the back seat made it worse? I would deduct that a little more baffling in the trunk should reduce it at least a little.

Mostly because you changed the shape of your driving "chamber" if you will.
The back seat acts like a soft barrier, changing the size of the cabin. When you laid it down, it changed the frequency that can resonate there.

[Sleez]

either fix the drone at the source, or turn up the stereo.

it's your car, do what you want, you have been given some great suggestions, and insist on focusing on deadening the sound passively. if that's what you want to do, do it, you don't need our approval.

but the only real way is to remove the sound before it comes out, via a different exhaust or J pipes. dynamat, peel and seal or whatever material you use, is just going to mask the drone, it will still be there.

good luck in whatever you do.

[2012REDSS]

I'm in the same situation as the op except I've already added the solo j pipes. It helped some but at some rpms mainly when under light accel or goin up hill the interior of the car has some serious vibes coming from the rear of the car. I've checked the pipes and they are not making contact with anything. I knew the JBA 3" was going to have some drone but I think some sound deadening in the trunk would help with the vibes.

[bthibodeaux]

If ou add a resonator just behind the cats, the drone and any popping you may have will go away. It worked great for me. The pics are of my old 2.5" system. I am now running 3" with resonator, which produces the same power that the 2.5" did before adding the resonator.

[OPP]

Originally Posted by Sleez

either fix the drone at the source, or turn up the stereo.

it's your car, do what you want, you have been given some great suggestions, and insist on focusing on deadening the sound passively. if that's what you want to do, do it, you don't need our approval.

but the only real way is to remove the sound before it comes out, via a different exhaust or J pipes. dynamat, peel and seal or whatever material you use, is just going to mask the drone, it will still be there.

good luck in whatever you do.

Chill!!! I'm just pointing out the difference of putting the seat down and asking for an explanation. Unobtanium gave a good explanation.