Exhaust drone after tummy tuck

HornedToad

TJ Enthusiast
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Aug 12, 2020
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Utah
After installing my tummy tuck, there is excessive exhaust drone (factory cats, factory muffler) while driving around. When setting up the exhaust mount that attaches to the transmission mount, I had to pull the catalytic converter towards the ground to keep it from touching the body (so that mount is now pulling the exhaust down a little rather than "holding it up"). The next exhaust mount (the one above the rear axle on the frame) is essentially doing nothing, and the last mount next to the gas tank is pulling up hard (rubber thing is pretty stretched) on the tailpipe. The solution seems to be to rework the exhaust and mounts to achieve an even "upward tension" from all three hangers. Who else has had a similar experience? How bad is it to pull down on the cat rather than push up on it? Can the cat y pipes be loosened and retightened at the manifolds to change its orientation in relation to the rest of the drivetrain or is it fixed?
 
When I did my tummy tuck it was immediately obvious the stock catback was not going to work. I had multiple interference issues. I started fresh because my muffler was rotted, but I think it is expected to have to do some exhaust mods. I wouldn’t be too concerned with pulling the cat down. If you loosen up the manifold bolts you should be able to get the cat downpipe in a neutral position.
 
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I had the same experience and needed to have the exhaust system re-worked by an exhaust shop.

Depending on how much of a tuck it is, that's the only way to do it right.

You might not like hearing this, but your stock catback exhaust is not going to work, plain and simple.

Welcome to the joys of tummy tucks. You'll always spend way more than you thought you initially would. Enjoy ;)
 
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Over the years i cant even count how many times my exhaust has had to be redone. Its finally in a state i consider perfect for my needs and HOPEFULLY no new mods have any effect on it. We will see...
 
Over the years i cant even count how many times my exhaust has had to be redone. Its finally in a state i consider perfect for my needs and HOPEFULLY no new mods have any effect on it. We will see...

Funny you mention that, I'm having Blaine re-work the exhaust for me while he has my TJ. Like you said, eventually you lose track of how many times you have to redo it.

With a big enough tuck, there's simply no way you can (or should) realistically try to reuse the stock catback.