Exhaust causing floorboard vibration

[Metz3020827]

Hey y’all, the more I look into this, the more it drives me nuts.

I have a roush catback (h pipe with roush mufflers so essentially a straight pipe with how little the mufflers actually do for volume) and notice even when I rev my car in neutral it vibrates the floor of my car.

of course you can probably expect some NVH from a full exhaust but is this normal? What can I look for? It’s done it since I’ve added the h pipe, and it’s starting to drive me nuts. I can constantly feel it when I drive no matter the speed. But I just figured out it happens when I just rev it in neutral (I don’t really ever rev my car like that lol) so I’m assuming it has something to do with my exhaust since nothing else would really be moving?

any ideas on what to make it better? It’s not intolerable since I’ve driven with it for like a year now with it as a catback. Unsure of what to do from here

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[Metz3020827]

Bump

 

[23GreenGremlin]

Chances are that somehow your exhaust is making contact with the floor or something directly connected to the floor. It may only be happening when you rev the engine, because the engine and trans can shift slightly (more if mounts are worn out) allowing something to make contact. Best way to figure it out is to get the car safely up in the air with the suspension loaded just like it sits on the ground (tires on ramps or blocks, not hanging) and have someone underneath while revving the engine to find the contact point. You can usually expect it to happen where the exhaust is already closest to any part of the floor or other structure. An exhaust shop with a lift can probably pinpoint your problem and make the necessary adjustments very quickly. Good luck.

 

[Metz3020827]

Chances are that somehow your exhaust is making contact with the floor or something directly connected to the floor. It may only be happening when you rev the engine, because the engine and trans can shift slightly (more if mounts are worn out) allowing something to make contact. Best way to figure it out is to get the car safely up in the air with the suspension loaded just like it sits on the ground (tires on ramps or blocks, not hanging) and have someone underneath while revving the engine to find the contact point. You can usually expect it to happen where the exhaust is already closest to any part of the floor or other structure. An exhaust shop with a lift can probably pinpoint your problem and make the necessary adjustments very quickly. Good luck.

So you think just adjusting the exhaust could alleviate my problem entirely? Nothing more severe than that?

 

[23GreenGremlin]

So you think just adjusting the exhaust could alleviate my problem entirely? Nothing more severe than that?

Super common problem. Sometimes it happens right after install and sometimes it happens after a bit of time. If a clamp isn't tight enough or you hit a good bump, the exhaust can shift a bit and suddenly make contact somewhere. Usually once you identify the location you just loosen up the nearest clamp, move the pipe slightly, and retighten the clamp.

If however, you have worn out motor or trans mounts, that are allowing the contact, you will need to replace them.

 

[Metz3020827]

Super common problem. Sometimes it happens right after install and sometimes it happens after a bit of time. If a clamp isn't tight enough or you hit a good bump, the exhaust can shift a bit and suddenly make contact somewhere. Usually once you identify the location you just loosen up the nearest clamp, move the pipe slightly, and retighten the clamp.

If however, you have worn out motor or trans mounts, that are allowing the contact, you will need to replace them.

Don’t the ford mustang motor mounts leak a ton of oil if they’re bad?

I’ve noticed the vibration since I installed the h pipe a year ago. People told me that it was normal though, just “NVH” but I beg to differ and now it drives me crazy.

 

[Metz3020827]

Super common problem. Sometimes it happens right after install and sometimes it happens after a bit of time. If a clamp isn't tight enough or you hit a good bump, the exhaust can shift a bit and suddenly make contact somewhere. Usually once you identify the location you just loosen up the nearest clamp, move the pipe slightly, and retighten the clamp.

If however, you have worn out motor or trans mounts, that are allowing the contact, you will need to replace them.

Also from a quick google search, the only “symptom” that is relative to a bad transmission mount is the vibration I get. The car is dead quiet, no clunks during shifts or anything. No hard shifts, etc. so weird.

 

[Cobra Jet]

You have to get under the car and look at the exhaust from front to back.

Somewhere along the way, something is touching either a cross member, or somewhere along the trans tunnel, or rear frame of the car. Stock or aftermarket exhaust will not vibrate the floor pan if mounted properly and NO contact between it and the vehicle.

Also check the A/C line along the passenger side frame rail. This is an area known where if that line makes contact with the inner frame rail or the inner fender, it will cause vibrations heard or felt.

 

[Metz3020827]

You have to get under the car and look at the exhaust from front to back.

Somewhere along the way, something is touching either a cross member, or somewhere along the trans tunnel, or rear frame of the car. Stock or aftermarket exhaust will not vibrate the floor pan if mounted properly and NO contact between it and the vehicle.

Also check the A/C line along the passenger side frame rail. This is an area known where if that line makes contact with the inner frame rail or the inner fender, it will cause vibrations heard or felt.

I’m starting to wonder if that’s what has been rattling in my backseat for the better half of a year. I took every panel off and it still rattles. I’m starting to get curious

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