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      08-10-2021, 08:46 AM   #1
kevmk81
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Chassis brace on bottom of vehicle - rattling

Since installing both an AWE midpipe, exhaust, as well as ER catted downpipe, what I *think* is rattling is the midpipe against the brace on the bottom of the car. What I have done was add a few washers between the brace and bottom of the car. Lately I've noticed that once again it's hitting that bottom brace. When I added the washers the noise went away entirely. I'm not sure I understand why the exhaust apparently keeps creeping down! The ER downpipe must have moved the exhaust further down I take it and that's why this is happening? Are there any downsides to me adding yet additional washers between that brace and the cars underside? I realize that brace is there probably to stiffen up the underbelly (reducing the chance for frame damage i guess? or maybe to keep body roll in control when cornering?). I guess I'm struggling to understand why the noise went away - and now is coming back. I would think it's a good inch or so away from the midpipe at this point! I'm just imagining what my exhaust pipes must look like moving around when going over bumps (noise only happens on certain sharp bumps in the road). Also - the noise only happens when the exhaust is cold. After driving for a bit - even the sharpest of bumps doesn't cause the clanging noise. When the car is cold and I hit a bump - not only can I hear it but I can feel it clang against that brace.
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      08-10-2021, 09:29 AM   #2
weehe126
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You probably should reposition the midpipe so it stops hitting the brace. When I installed my dinan midpipe it rotated/settled and started to hit the brace. So I repositioned it and tightened the clamps.
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      08-13-2021, 10:13 AM   #3
chris-c
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It's the clamps that hold the two exhaust sections together. The rear section wants to stay in place because it's just hanging there and the front one wants to twist and move because it's connected to a moving engine.

Where they join they'll move apart becoming longer and when it's longer it droops down in the middle. I've had this issue so many times but it's easy enough to fix with a jack. Just lift it up, undo the mid clamp, push the exhaust together and re-clamp it. Mine wasn't an issue until I went up in power and now i'm running 600+ it happens quite frequently. I run the MPPSK so it might be a different exhaust but I'm fairly sure they're all joined at the back/mid area and this is the problem point.
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      08-13-2021, 11:26 AM   #4
kevmk81
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Quote:
Originally Posted by chris-c View Post
It's the clamps that hold the two exhaust sections together. The rear section wants to stay in place because it's just hanging there and the front one wants to twist and move because it's connected to a moving engine.

Where they join they'll move apart becoming longer and when it's longer it droops down in the middle. I've had this issue so many times but it's easy enough to fix with a jack. Just lift it up, undo the mid clamp, push the exhaust together and re-clamp it. Mine wasn't an issue until I went up in power and now i'm running 600+ it happens quite frequently. I run the MPPSK so it might be a different exhaust but I'm fairly sure they're all joined at the back/mid area and this is the problem point.
Yeah that's what I've noticed. I rotated the midpipe a couple nights ago then tightened the clamps to 60 ft lbs. I was thinking that if it moves out of adjustment again that I may have one of the clamped areas spot welded with a small weld as well as tightening down the clamps again. Or maybe weld both clamped areas for that section of exhaust? I mean the stock exhaust is an entire piece anyways so it's not like there's potential for damage.
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      08-15-2021, 12:14 PM   #5
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You should just be able to loosen the clamps, twist it to give clearance and tighten again.

Spot welding the joints is common exhaust practice to prevent parts moving later, but just make sure it's right before you do it, or undoing that isn't a lot of fun.
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