Exhaust Harmonic Vibration

[White SSVR]

Hi,

Long time stalker, first time posting.

I recently installed a full exhaust from a Gen-F 340kw Clubsport on my S1 VF SSVR and I now have a bad harmonic vibration. It occurs between 1200-1600rpm and is worse under load. I can feel it through the seat and floor on the drivers side but not on the passengers side. The vibration also sounds a lot louder on the drivers side from inside the car.

I've put my car up on a hoist and checked all the rubber mounts, bolts, heat shields and made sure it's not touching anything else. I've even tried changing the rear mufflers and the harmonic vibration is still there.

Has anyone come across this or have any ideas on what might be causing the vibration? Thanks in advance.

 

[426Cuda]

I have the same set up on my VF1. Mine does this a bit too. Not bad though. I thought it was probably due to the system not having the flex joints the standard one had? But the, the standard one was whisper quiet too.
It is harmonic, as you say and can probably be felt through the steering wheel too. I just don't notice due to familiarity. No one else has ever commented on it to me though. Short of going back to flex joints, I'm not sure if there"s much you can do?Perhaps try some rubber grease in the support rubbers. You may just have to get used to it?

 

[BLACK-VE]

Hi,

Long time stalker, first time posting.

I recently installed a full exhaust from a Gen-F 340kw Clubsport on my S1 VF SSVR and I now have a bad harmonic vibration. It occurs between 1200-1600rpm and is worse under load. I can feel it through the seat and floor on the drivers side but not on the passengers side. The vibration also sounds a lot louder on the drivers side from inside the car.

I've put my car up on a hoist and checked all the rubber mounts, bolts, heat shields and made sure it's not touching anything else. I've even tried changing the rear mufflers and the harmonic vibration is still there.

Has anyone come across this or have any ideas on what might be causing the vibration? Thanks in advance.

I'd loosen the bolts of a bit and see it that helps settle the exhaust down a bit, is there extra tension on any rubber mounts.

Once fitted a system and even though seems all good with clearance the engine twisted made system touch underbody sometimes. Adjust the exhaust and no issues

 

[duaned]

Had the same issue with my first VF when I fitted a HSV exhaust. Fitting flex joints before the rear mufflers eliminated the bulk of it for me.

 

[Not_An_Abba_Fan]

That's exactly it, the factory exhaust has flex joints for a reason. When going aftermarket, they "tune" the resonators to take that out. (As in length, internals and position). OEM fitted flex joins to take the vibration out.

Another thing to look at is the body brace half way down, make sure the exhaust isn't touching that.

 

[Witto]

I only notice it when the AFM kicks in, I could also feel it with the stock system, but not as much.

 

[Murdoch]

same system on mine. No resonance
I put flex joints at the rear though when the shop fitted it. Maybe that helps?

 

[426Cuda]

same system on mine. No resonance
I put flex joints at the rear though when the shop fitted it. Maybe that helps?

No doubt about it.

 

[treesnake]

On my SV6 I had a painful resonance at about 800 RPM, so when coasting in reverse our of the driveway the right window would vibrate. Turned out the flex joint for the rear muffler amplified the vibration coming from the engine, essentially vibrating the rear muffler harder. A fixed joint where the rear muffler is dampened the vibration and fixed the issue.

Yes under load the engine mounts stiffen up (engine locking to one side) and transfers the vibs more, increasing the vibration amplitude in the system.

Adding flex connections to the front and rear of the exhaust could help, or make it much worse. From the posts above with similar setup its definitely worth trying.