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To go with aftermarket transmission mounts such as UUC or Rogue, are there any aftermarket engine mounts that would be benficial to helping reduce drivetrain slack, wiggle, etc., even further?

I read on Rogue's site that BMW"s Motorsport mounts can cost > $500, if you can find them. Has no one else made an aftermarket, affordable, and effective, motor mount?
 

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Ireland Engineering (http://www.bmw2002.com/) has made Urethane motor mounts for E30s, E36s and other BWMs. I have them on my M3 and they completely got rid of the vague shift gate location under hard cornering (combined with Rogue tranny mounts). They don't currently have anything listed for E39s, but maybe they would make some if there's enough interest.
 

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i think our motor mounts are oil filled and the msport are either solid or metal. i talked to ben about this once but i dont remember.
 

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Unless you are a hard core track junkie and don't mind vibration, a solid or urethane motor mount is probably not a good idea. See this related thread for another owner's vibration issues possibly related to motor mounts. Even urethane tranny mounts w/enforcer cups can transmit unwanted vibration though this can be minimized with proper installation.
 

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The majority of driveline slack comes from the allowed vertical movemnet of the mid-propellershaft CV joint support bearing. That bearing sits in a rubber mount with about 2/3 inch of movement vertically (and sideways too).

This is the thing that goes thump under the car when you accelerate hard and abruptly let go of the accelerator pedal.

I assume it is designed like that to lessen shock loads on the propellershaft.
I think, even if you mount the engine rigidly you will still have a lot of play.

David
 

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Some more random (and not necessarily relavent) thoughts:

The reason that most people replace motor and transmission mounts with Solid Aluminum or Urethane is that with the stock mounts the transmission and engine move relative to the shift linkeage during hard cornering (R compund tires while driving on a racetrack). This is responsible on E36s for miss-shifts such as downshifting into second instead of fourth gear which causes an over-rev and valve and possibly piston damage. I haven't heard that over-revs are as much of a problem on E39s as they are on E36s.

If the oil has leaked out of a fluid filled motor mount as happens with age, it might cause an increase in NVH (Noise Vibration and Harshness) because the mount collapses on itself. The NVH won't be cured by a Urethane motor mount, in fact it might be made worse. Some of the other cars I have owned (Porsche 928) also have fluid filled motor mounts which do indeed collapse with age and increase engine vibration. The Porsche mounts are very expensive so some people have sucessfully substituted a Ford truck part number. I have no idea if there is a non-OEM substitute available for M5s or not (and some people will at this point pronounce me a heretic for suggesting such a thing).

It is very true, however that there is an increase in NVH when you install stiffer engine and tranny mounts than stock. My M3 is almost entirely a track car these days so I don't care so much about that. For a street car, your tolerance level for NVH will determine whether solid mounts are aceptable for you, I can't imagine that there's any performance reason to install them in a street car since it will never see the kind of cornering loads experienced on the track. If there is a cost benefit and you can live with the extra vibration they might be a solution to the expensive OEM motor mount problem (if there is one).

Regards
 

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Has anyone installed urethane engine mounts or any other aftermarket ones? How long does the OEM mounts last?
 
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