Vibration with new torque arm?
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From: Bridgewater,Ma
Vibration with new torque arm? Car is a 02 SS A4.
pinion angle set at 2 degree's.
I put a solid mount torque arm in(I think stealth,customer car)That the front mount is on the tranny cross member.At first I had a Nasty vibration from 75mph and up,in gear and nutural.Then I installed another driveshaft which moved the vibration to 90mph and up.
Would this be caused from the torque arm?Is there a solution to this?
Thanks
pinion angle set at 2 degree's.
I put a solid mount torque arm in(I think stealth,customer car)That the front mount is on the tranny cross member.At first I had a Nasty vibration from 75mph and up,in gear and nutural.Then I installed another driveshaft which moved the vibration to 90mph and up.
Would this be caused from the torque arm?Is there a solution to this?
Thanks
Re: Vibration with new torque arm? The torque arm is like a tuning fork or
pendulum, it has its own resonant frequency
with the axle being the "spring" and the
arm being the "mass". So there's going to be
some frequency at which the thing will want
to ring. However, I think it's more likely
that the hard mount is simply transmitting
rear end vibrations (driveshaft imbalance,
u-joint bind, tire imperfections, ....)
more efficiently to the body sheet metal.
With no rubber anywhere to damp it, it's not
surprising that it could get a little harsh.
If the pinion angle is significantly changed,
and the front & rear angles are not identical,
this makes U-joints show some bind and need
more fore/aft slip. This might be worth some
fiddling, see if the angles are eyeball-off
and see if you change the adjutments, if the
vibe goes away.
Any chance of, say, putting a rubber sleeve
on the fore end, trying a soft mount, etc.?
At least as a diagnostic cut, to narrow it
down.
pendulum, it has its own resonant frequency
with the axle being the "spring" and the
arm being the "mass". So there's going to be
some frequency at which the thing will want
to ring. However, I think it's more likely
that the hard mount is simply transmitting
rear end vibrations (driveshaft imbalance,
u-joint bind, tire imperfections, ....)
more efficiently to the body sheet metal.
With no rubber anywhere to damp it, it's not
surprising that it could get a little harsh.
If the pinion angle is significantly changed,
and the front & rear angles are not identical,
this makes U-joints show some bind and need
more fore/aft slip. This might be worth some
fiddling, see if the angles are eyeball-off
and see if you change the adjutments, if the
vibe goes away.
Any chance of, say, putting a rubber sleeve
on the fore end, trying a soft mount, etc.?
At least as a diagnostic cut, to narrow it
down.
