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Discussion Starter #1
Evening All,

After a quick enquiry today, it seems feasible to look at the development of some uprated engine mounts. It seems recently that there are a lot of moves towards transmission and differential mounts and subframe bushes, so I'm happy to bow out to these, but after a fair bit of research, it seems engine mounts are a weak link on these cars. Being fluid-filled, they eventually tear and leak, and this seems to be a problem on not only standard M5's, but also the other V8 E39's, the 540, for example. I can only imagine how the even higher torque SC'd cars cope. Does anyone know if the M5 and 540 are the same mount? I've not had chance to check yet as I'm working on tonight.

So the plan is simple, I'm looking into uprated engine mounts and am happy for my car to be a test bed for these items. There is also the chance that they may be available in different ratings, fast road and competition, depending on requirements.

I have some unfitted, new Rogue transmission mounts that I'm also going to send off to see if these can be improved in any way. Always a chance.

Any offers of standard mounts to borrow would obviously be gratefully received, otherwise I'll buy these myself and then ebay them.

Please feel free to comment, and any suggestions for other items in the same vein, any possible interest would be good to, it might move it all forward a bit.

All a touch theoretical at the moment, but I'm keen to move this forward :)

Cheers all
 

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E39 M5 uses the same engine mounts as E38 750.
E39 540 uses the same as 740 also.
 

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I wasn't aware that the stock mounts were a weak point. No they're not solid but they don't need to be. I have 106k miles on my original mounts and they are in fine shape...I don't race my car too often but I don't baby her either....seems like you can't ask for more than that.

But good luck to you.
 

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Discussion Starter #4
All good feedback, and if that's the case then all good.

I was just going on feedback like this : E39 Motor and Transmission Mounts - Bimmerforums - The Ultimate BMW Forum

In my experience, these things can be improved with a more resilient mount, not solid, just stronger.

If it's a no-goer, I'll just get them made for me, it's not an issue, just thought I'd share :)
 

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They definitely can be improved upon. The stock ones last, but they frequently tear after a few bouts of really spirited driving. One typically does not notice it--until you replace them with new ones, then wow, what a difference it makes. I'd love to have some made out of Delrin.

--Peter
 

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I'll try to help.

Can anyone show me prints of what you have in mind? Let's take Peter's delrin mounts as an example, can you sketch up or send me
cad files of your ideas?
I do have a machine shop in my garage, that I'm not using much at the moment, and have made several motor mounts for my vintage
racing CanAm buddies.
Send me your ideas and I might whittle same R&D parts to help this little project along. (Peter will owe me a blast in his beast if they work though).

Randy
 

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Can anyone show me prints of what you have in mind? Let's take Peter's delrin mounts as an example, can you sketch up or send me
cad files of your ideas?
I do have a machine shop in my garage, that I'm not using much at the moment, and have made several motor mounts for my vintage
racing CanAm buddies.
Send me your ideas and I might whittle same R&D parts to help this little project along. (Peter will owe me a blast in his beast if they work though).

Randy
I have some brand new mounts sitting 6 feet from me right now, and will have my old set out soon if it would help..
 

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Discussion Starter #8
Guys, in this diagram, exactly which parts are we looking at for the rear of the car? I'm thinking :

4x #2 (33311091422) Subframe bushes
4x #4 (33311093936) Stoppers (to create the complete unit on the car)
2x #9 (33171093008) Rear diff mounting bushes
1x #6 (33171090389) Front diff mounting bush

Is this the setup we're looking for at the rear, something that's not solid, but where the replacements would last longer than standard, on both standard and modded cars?
 

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Discussion Starter #9
Also, part #6 in this diagram, the thrust arm bush? Although I am thinking that Powerflex make replacements for these, I was just wondering if anyone had anysuggestions as to how this could be improved, but not as harsh as some people say they are. Again, no flaming manufacturers, but it's a documented issue that some say they are too harsh...
 

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Powerflex does thrust and front control arm bushes,so no need!


I hope you guys are aware that if you replace the diff bushes with urethane,massive re-inforcement of the front bushing housing is required.

The stiff bushes will rip the diff out of the subframe(it does that even with stock bushes)...


Changing the rear subframe bushes to something more rigid increases the risk of ripping the subframe out of the chassis(see E46 M3 issues)...


The stock engine mounts are fine(if they are new).Even if the car has 800hp....

Stiffer engine mounts increase vibrations transmitted to the body big time.And also increase the risk of breaking the stock aluminium mounts on the block doe to stress and vibrations.


Been there,done that.

I am a huge fan of improvement on these cars,but you guys are barking at the wrong tree there!

Anything that is not proper researched,developed and tested will only increase the risk of damage to expensive parts.


My recommendation is for anyone who has worn engine mounts,replace them with new ORIGINAL(not the aftermarket crap) mounts and you will see it really transforms the car!
Makes the front end much tighter!

Experienced that on several S62s...
 

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Discussion Starter #11
:) If this is the case then I'll hang fire, I clearly haven't managed to find the right threads to find this stated before, I'm sure it's been mulled over in the past, so apologies for not being entirely on the ball.

Again, many thanks for everyone's feedback :)
 

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The problem is very often that "improvements" can cause much higher stress on the parts they are attached to.

There is a reason why engine mounts,diff mounts,subframe mounts are designed on a street M5 as the weakes links.

To prevent damage in other areas to happen.

With stuff like that,you have to see the whole picture,not only the single component.

Let's take E46(WTCC,GT,whatever) race cars for example,they have usually aluminium or urethane replacements of the subframe bushings.

BUT,the mounting points are re-inforced as well as the roll cage extended and welded additionally to the mounting points...
 

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Discussion Starter #13
Absolutely, yes. The general reason modded cars get a bad rap, uprate one thing and it stresses the next link down the line, give it more power and then come gearbox problems.

Like I say, perhaps a lack of thought on that one. I'm just one those people who likes to make things stronger, and last longer (more reliability...now!), perhaps this isn't the area to do it :)
 

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Absolutely, yes. The general reason modded cars get a bad rap, uprate one thing and it stresses the next link down the line, give it more power and then come gearbox problems.

Like I say, perhaps a lack of thought on that one. I'm just one those people who likes to make things stronger, and last longer (more reliability...now!), perhaps this isn't the area to do it :)

If you consider that stock engine mounts and subframe mounts last at least 50k miles,it is really an option just to go for new OEM stuff,take it out of the box,bolt it on and be done with it...

I have a similar approach you have regarding making things better on these cars.

But very often,after long thinking about it,I go for new original stuff.I just have no intention to have to deal with issues like the ones I pointed out,and rather change the original parts that are known to work more frequent...
 

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got this from powerflex this morning regarding subframe bushes:-

I'm afraid until we have completed it and the parts are ready for general release, I couldn't any indication of price

This is already one of our next projects so it should certainly be within the next 2-3 months, I just can't give a more accurate timescale as with development the goal posts can move very quickly

Kind Regards

James Bourn ~ Sales Manager

***************************
EPTG Ltd
POWERFLEX
7 Union Buildings
Wallingford Road
Uxbridge
UB8 2FR
ENGLAND

Tel: (+44) 01895 460033
Fax: (+44) 01895 520095
[email protected]
Powerflex
***************************



...so there should be aftermarket subframe bushes for the e39 m5 out this year, but i guess re-inforcement issues are something to think about.
 

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Guys, in this diagram, exactly which parts are we looking at for the rear of the car? I'm thinking :

4x #2 (33311091422) Subframe bushes
4x #4 (33311093936) Stoppers (to create the complete unit on the car)
2x #9 (33171093008) Rear diff mounting bushes
1x #6 (33171090389) Front diff mounting bush

Is this the setup we're looking for at the rear, something that's not solid, but where the replacements would last longer than standard, on both standard and modded cars?
Are the 4x #4 recommended when replacing the subframe bushings? And all new hardware?
 

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Discussion Starter #17
As far as I knew, these were the subframe bushes themselves, but happy to be corrected on that.
 
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