Insulation between exhaust and floor to stop vibration

[DasHooch]

I'm trying to get rid of exhaust vibration occurring at low rpm. The exhaust develops a good rattle from the engine's stiffer polyurethane mounts. I think it's constrained at the header and the muffler with a good shake in-between. There are other hangars, but they allow the vibration movement.

A bit of pressure on the pipe will stop the noise. I found this out by lightly pressing my shoe on it while I was under there. I'm considering getting some exhaust insulation and jamming it between the floor and the exhaust to create the pressure. Is this nuts? Should I instead get a shop to weld a new hangar location that tensions the pipe a bit?

[Phil@rise]

Yes what your thinking of doing is nuts. Fix and or replace your faulty hangers properly.

[DasHooch]

Alright. So I see two options with hangars. Looser or tighter.

A. Change the muffler hangars to hang looser, or

B. Add another hangar in the middle, in such a way that the rubber hangar is in compression or tensioned to one side.

[Phil@rise]

Your hangers should all be in tension basically pulling against each other from the exhaust to the body to keep it tight and rattle free.
Basically if you have one on the right side you should have one on the left side and so forth.

[Muskys SS]

Sounds like you may need a flex pipe. Vibrations like that can develop cracks over time. What Kind of car is this?

[DasHooch]

There's no flex pipe, just a somewhat adjustable joint at the header and midpipe. I think a side hangar will do the trick.