ChaSSe

So I just bought a 1999 Z28 with a BMR Lower Torque Arm Relocation Crossmember and I hate it. It vibrates too much for my taste. Has anyone else had this issue? Anyway to fix it? I would just get an OEM one but I cant find them anywhere..

vjo90rs8

iTrader: (9)

with the torque arm mounted to the transmission the torque arm is isolated from the body by the transmission mount and torque arm bushing. The torque arm relocation kits mount directly to the body so the torque arm is now only isolated by the torque arm bushing. What torque arm does the car have? I would stay install a rubber torque arm bushing but it is probably impossible to find one that works with the bracket and an aftermarket torque arm.

ChaSSe

http://www.bmrsuspension.com/?page=p...&productid=327

This is what I have..

Deviant LS1

iTrader: (4)

Its going to transfer the movement of the rear end to the floorboard. Loading (accelerating) and unloading (cruising) the rearend will cause the torque to move vertically up and down. This sounds almost like a popping or slight tap. Any noise from your rearend also gets stethoscoped to the floorboard and it makes it sound louder now that the noise is right next to you instead all the way in the back.

It's going to make more noise than stock. I've learned to live with it.

BMR Sales2

iTrader: (40)

First off make 100% sure that the pinion angle is correct if this is off than there will be more vibration than there would normally be. Also if you have a poly-urethane transmission mount than there will be an increase in noise. Since that setup mounts the torque arm directly to the chassis there is a good chance of some additional noise over the stock setup since it mounts to the trans rather than the chassis.

ChaSSe

How would I make sure about the pinion angle being correct? Im also pretty sure that it is a poly mount because it is way stiff.

jimmyblue

iTrader: (11)

I had the same problem with a Yank relo member.
Even went as far as trying to put rubber between
it and the car, no help. Best you can do is "minimize"
driveline vibration by getting the driveline angle
(which is -not- pinion angle, PA is only half of it)
to net zero under some condition - you will have to
decide whether under load, or at cruise, matters
more. Because soft parts in the suspension will let
the angle vary with load, as well as the asymmetry
between LCA and TA grometry imposing an angular
change at the pinion under squat / rise.

I have what I think was a cool little idea for a
"street/strip" TA relocation, I've sent it to some of
the suspension vendors but no evident interest.
So what the hell, here is is for the world to see.

Maybe somebody wants to weld up their own, it's
rather simple really. Idea is that the mount attaches
to the trans tail above the soft mount where tail
mass and bunge can soak up the vibe. Then you
just need compensating shim plates outboard to
get the net height / angle difference back to zero.

BMR Tech2

iTrader: (5)

It is a poly mount and there is generally sufficient bushing isolation to absorb a majority of the driveline harmonics and road noise. Everyone has their own opinion on what is acceptable and what is not, but generally we have found that our 75 durometer polyurethane, especially in this specific application, works well for the majority of users. As Kyle pointed out above one of the easiest things to check first is the pinion angle. Here is a direct link to our Pinion Angle Adjustment How-To Video.

01ssreda4

iTrader: (96)

Listen, I'm running the same bracket and hated it also. However, I found out that it was another issue with the driveshaft that was actually causing the vibration. Once I got that fixed there is NO vibration. You have other problems, I'd suggest finding/fixing them.

ChaSSe

The vibration is while in gear and in neutral, thats what has me stumped.

jimmyblue

iTrader: (11)

In gear and neutral, the driveshaft spins and the U-joints bump over
just the same. Unless you're parked. Load adds to it but not much
difference in suspension geometry between coast and cruise.

01ssreda4

iTrader: (96)

Right, neutral (while rolling) eliminates the engine as a source of vibe because rpm drops. Driveline rpms remain.

ChaSSe

I meant to say while parked. Sorry to leave that out. The vibration completely matches the RPMs if moving or parked. Higher RPM more vibration, Lower RPM less vibration.

SS SLP2

iTrader: (8)

[QUOTE=ChaSSe;15359975]I meant to say while parked. Sorry to leave that out. The vibration completely matches the RPMs if moving or parked. Higher RPM more vibration, Lower RPM less vibration.[/QUOTE

^^^ by this I think you just passed the problem being TA or angle problem> are you std / a4 ?
I would guess front engine pulley / enturnal engine/ fly wheel/ flex plate/ clutch /presseue plate/ loose TC/ front or rear trans bearing

stating as 6 spd or A4 may help elemate several possibles
just my .02' Johnny

01ssreda4

iTrader: (96)

If you are getting vibration while parked, its from the motor/converter/flexplate. Thats the only thing spinning.

ChaSSe

Its an M6

01ssreda4

iTrader: (96)

Ok, well it would be the motor, balancer, flywheel, or clutch.

ChaSSe

I think I found the issue. I looks like its solid (well close to no bushing) mounted.



Compared to this...

01ssreda4

iTrader: (96)

Sorry buddy, that bracket isn't causing vibration when you are sitting still in a parking lot.