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I like the way my 34 coupe sounds on the outside but I would like to quiet the exhaust noise down on the inside. My pipes run from the headers outside the frame rails, under the running boards and straight back. The mufflers are tucked up under the running boards. Its a glass body and the doors and floors are pretty well insulated. For those that have been there done that, will wrapping my pipes from the headers to the mufflers and wrapping my mufflers make a big difference in the interior sound level? Pipe hangars have rubber isolators and I don't have much room above the pipes or the mufflers, maybe 1/2". Trying to keep that stuff out of sight.

Thanks
Bud
 

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bentwings
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I don't think you will get much sound deadening by wrapping the pipes and muffler with a side exhaust.

If you change to an ex exit behind the rear of the car it will help.

You may have to put some Hush mat inside the car. This helps with the drumming or drone.

I have a lot of wraps on my car more for insulation of the starter and floor. It works very well for this. I drive quite a bit in the rain and frequently wash the underside of the car. The pipes are 3" aluminized and the headers are Jet Hot coated. After 5 years I see no rust at all on the wrapped areas. I have changed the wrap a couple times as it seems to rot out after a while but nothing on the ex system.

It is really difficult to reduce ex sound in a "plastic" car. The road noise goes away pretty easily but ex seems to go right thru any insulation. Keep in mind that automotive engineers spend a lot of time and effort to reduce noise from everywhere. They also have many people whose only job is to do this and lots of computer power. We only have trial and error.....mostly error. haha:(
 

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What about a rhino-liner type product on the underside of the floorboards? I wonder if you have enough room for a resonator. Do you have a crossover/ x pipe. I don't think any one thing will cure your problem, but taken together it may help some.

What exactly do you have for an exhaust? Pipe dia, muffler type etc; and how big is your motor?
 

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Since you said the doors and floor are pretty well insullated, assume you have Hushmat or Dynamat inside the doors and on the floor under the carpet. Underneath the floor and running boards, Lizardskin helps with heat and sound. It looks like the Rhinoliner, but contains micro-spheres that really make a difference. They have heat control and sound control blends. It goes on with a sprayer like undercoat. Some of the places that sell it will loan/rent you the gun.
 

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bentwings
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I don't have an "X" pipe on my Willys. There just is not a lot of room for this with 3" ex pipes... Master cyl and booster, e-brake stuff, trans, drive shaft, mufflers, and crossmembers needed for the pro street frame.

Frankly, I'm not impressed with the X pipes. IF there is some power increase, I simply do not need it. It's far easier and more effective to just change the blower pulley.

There is a lot of sound radiating out of the mufflers and the mfg spend a lot of computer time designing this out. We simply do not have this capability. I have a friend that has a 440 Mopar with Flow Masters that is outright uncomfortable to ride in. I doubt, like me, that he has had it "on the mat" all summer. He would be better off with some cheapo turbo mufflers.

Even adding some kind of resonators may help but the majority of the sound is already out of the muffler by then.

I took the resonator off of my 1 ton diesel dually and it made no difference in sound at all. Now removing the muffler is a different story. haha

I've often thought that holding a sound meter at different points around the car would give some indication of where larger amounts of noise is coming from but I don't have access to this any more. You will see on modern cars there are various places where a square foot or so of sound deadner has been installed. This is usually a heavy material sometimes with a layer of lead in it. It's purpose is to soak up sound energy and change the frequency possibly to cansel out other sound. Again this done by computer analysis.
 
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