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Exhaust Arm Breaks?

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Hypergram

Hypergram

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Thread Starter #3
Really...crazy...is the exhaust ok? What hangers bushings you running?
Just got home. Exhaust looks ok. I'm running Torque Solutions, the old Whoosh ones. It wasn't the bushings fault, when Mountune sent my exhaust it didn't fit properly, so a shop welded metal to my car's hanger arm to extend it. It worked great, till now.
 
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#5
This problem was something I was thinking about when shopping for the ST. Every video I watched showed massive movement forwards/back and hilarious side to side rattle! The day after I took delivery with 70 miles on the odo, I went to my regular performance exhaust shop and explained how much our system moves around in stock form. He ended up adding some pretty decent welds to the hangers/tubing when doing my muffler and resonator delete. After minimizing engine movement with all 3 mounts upgraded and dropping ~30lbs from the system, I figure I'll never have issues. With zero road salt and my FiST yet to see rain in 19 months of ownership eliminates potential corrosion factors;)
 
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#6
Why didn't or don't you just get an extended hanger? Many companies sell them and they relatively cheap ($10-15). Your exhaust shop is to blame for that, not the exhaust. I run the same exhaust and agree it sits close to the valence, but it's an easy fix with an extended hanger.
 
OP
Hypergram

Hypergram

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Thread Starter #7
Why didn't or don't you just get an extended hanger? Many companies sell them and they relatively cheap ($10-15). Your exhaust shop is to blame for that, not the exhaust. I run the same exhaust and agree it sits close to the valence, but it's an easy fix with an extended hanger.
Do you have a link to those? I would be happy to pick some up. I would have preferred them to be stiff like the ones I purchased. I don't want them crashing around everywhere.
 
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Hypergram

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Thread Starter #8
So, I guess after class today I need to take off my muffler again? I don't know how I would get it to a shop otherwise... Zip ties and duct tape? And what even would I say to them / would they even be able to do anything? I doubt traditional Tires Plus or something would be able to do anything. You think a dealer will help? A muffler shop would probably be better.
 
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OP
Hypergram

Hypergram

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Thread Starter #10
To bad you don't live closer, I'd repair it for you. I'm a 4955 welder in the Navy. A good weld would not have broken due to a little rattling.

Sent from my moto z4 using Tapatalk
Thank you very much for the offer. It's appreciated. The guy who did the weld is an ASE certified technician who works on exotic cars everyday... I don't know how he could have screwed up? It should be a pretty easy procedure I though.
 
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Hypergram

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Thread Starter #12
Thank you. Upon further inspection, it wasn't the weld that snapped but was rather a piece of metal that completely sheared in half. How does that even happen? A friend and I got some zip ties from Walmart which seemed to hold it properly in place temporarily until I take it to a shop tomorrow.
 
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#13
If the metal was vibrating enough it could have stressed the metal. Heat from the exhaust can also make metal weak because of heat cycling so with those 2 things happening it would make the metal brittle and then shear it due to vibrations.

Sent from my moto z4 using Tapatalk
 
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Hypergram

Hypergram

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Thread Starter #14
If the metal was vibrating enough it could have stressed the metal. Heat from the exhaust can also make metal weak because of heat cycling so with those 2 things happening it would make the metal brittle and then shear it due to vibrations.

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Interesting. I'll have to keep an eye on it in the future. Well I got it fixed. $25. Pretty great considering.
 
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#15
Interesting. I'll have to keep an eye on it in the future. Well I got it fixed. $25. Pretty great considering.
Just to sort out the metallurgy issue here... The heat wouldn’t make the metal brittle, and the vibrations create what is known as high-cycle fatigue. If the number of cycles exceeded the fatigue limit ( which is the function of the material’s mechanical properties), the piece would break by cracking. I had several failures of the ATP charge pipe support tab (the geometry is similar to the exhaust hanger arm extension) for this very reason.
 

babyivan

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#16
Just to sort out the metallurgy issue here... The heat wouldn’t make the metal brittle, and the vibrations create what is known as high-cycle fatigue. If the number of cycles exceeded the fatigue limit ( which is the function of the material’s mechanical properties), the piece would break by cracking. I had several failures of the ATP charge pipe support tab (the geometry is similar to the exhaust hanger arm extension) for this very reason.
Heat does weaken metal. However, not sure if that translates to it getting brittle.

I just watched a doc on 9/11, and they go into a whole thing about metallurgy.

2017 w/Recaros - bone stock
 
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#17
Heat does weaken metal. However, not sure if that translates to it getting brittle.

I just watched a doc on 9/11, and they go into a whole thing about metallurgy.

2017 w/Recaros - bone stock
So - you are correct, elevated temperature does reduce the yield strength of material, but I was referring to the temps that exist under the car - the effect is negligible. The temps in the WTT fire were more than an order of magnitude higher.

Also, elevated temperature would make the metal softer, which would reduce the susceptibility to brittle failure.

Kudos to your paying attention to the materials performance stuff!
 

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