Motor, Transmission, and Differential Mounts

[Ggeezer]

Originally Posted by ///Mobbin

After two not so great engine mount experiences (manufacturing quality issues both times), I'm finally ready to try another set. For the one track weekend I experienced aftermarket mounts during, they were great, my car felt extremely dialed in.

Trying to decide between the AKG Poly mounts and Black Forest Industries Stage II or III. I only drive my car on the street 3-4 times a month now so NVH is not a huge concern, I still want some semblance of street-ability though.

Anyone have any feedback on the BFI mounts? ilikebmxbikes I recall you mentioning them in another thread, did you go Stage II, any thoughts?

What was the issue with your Vibra Technics mounts?

[roastbeef]

just to reflect back on my vibra technics mounts- when i had my rod bearings done they were in good shape.

[Ggeezer]

Originally Posted by roastbeef

just to reflect back on my vibra technics mounts- when i had my rod bearings done they were in good shape.

Good to know. I'm thinking of picking some up from the group but going on.

I'm at 53k on my 08 so I think they're due for a change.

[aus]

Group buy info here: http://www.m3post.com/forums/showpos...2&postcount=27

[Mvez]

Just installed a set of BW mounts and I don't find them offensive at all. Much less vibration than the Rogue poly mounts, and they will soften up a bit more unlike the poly. Happy with them.

[SYT_Shadow]

Originally Posted by Mvez

Just installed a set of BW mounts and I don't find them offensive at all. Much less vibration than the Rogue poly mounts, and they will soften up a bit more unlike the poly. Happy with them.

I've been running the BW ones as well for a year and pretty happy with them. Barely noticeable over stock and only at idle. Everywhere else it's more immediate but never harsh.

[jid2]

I installed the BW mounts this weekend during my rod bearing install and find them seriously harsh. There is significant vibration and noise at idle and during clutch transitions (with DCT). I saw some comments about the torque on the top nut, is it possible I went too far?

[SYT_Shadow]

Originally Posted by jid2

I installed the BW mounts this weekend during my rod bearing install and find them seriously harsh. There is significant vibration and noise at idle and during clutch transitions (with DCT). I saw some comments about the torque on the top nut, is it possible I went too far?

likely they need to break in. Mine did during a couple thousand miles, although the only time they were harsh was at idle

With a raised idle I would be hard pressed to notice the difference

[slicer]

Originally Posted by SYT_Shadow

likely they need to break in. Mine did during a couple thousand miles, although the only time they were harsh was at idle

With a raised idle I would be hard pressed to notice the difference

FWIW - I have them and also don't find them to be harsh (I have DCT). Something could be wrong with your install.

[SYT_Shadow]

Originally Posted by slicer

FWIW - I have them and also don't find them to be harsh (I have DCT). Something could be wrong with your install.

I'm also DCT

On my 6MT car I replaced with OEM as that's supposed to be a street car

[135]

Has anyone tried (or thought about trying) solid engine and transmission mounts, e.g. something similar to these

https://www.turnermotorsport.com/p-1...ion-mount-set/

https://www.turnermotorsport.com/p-3...ion-mount-kit/


And the solid diff mounts:
https://www.turnermotorsport.com/Sea...sedClearance=1

https://www.turnermotorsport.com/p-1...2-e9x-f22-f3x/


To suit an occasional street driven car with compromises for track use.
Also on an auto/steptronic/DCT.


Turner currently has these for 15% off - today is possibly the last day for the sale.

[pbonsalb]

Those look miserable. Major compromises. Definitely a track car only thing. If your only street driving is to the track and you don’t really care about NVH at idle and lower rpm where it is noticeable because you are never at idle or low rpm because race car then go ahead. Solid motor and trans mounts are really dedicated racecar parts.

[135]

Originally Posted by bigjae1976

I just put solid engine and trans mounts in my E46 M3. No track time yet but it quite loud. Again, the shifting is much improved.

I'm sure throttle response is improved but I can't perceive any difference.

Originally Posted by pbonsalb

I have run them on my E36M3, which uses the same mounts as an E9xM3, for about 5 years. They add some NVH noticeable at low rpm. More than Bimmerworld Group N replicas, which I have also run.

Poly motor mounts, even the AKG 75D, are not offensive to me on a daily driver. Bolt through or solid mounts are.

On the E36M3, I tried red poly bolt through trans mounts, and could not get them out of the car fast enough. I would go softer on the trans mounts, which are essentially rear engine mounts, than on the engine mounts, for a street driven car.

Same goes for subframe and diff mounts. Go hard on the subframe mounts and softer on the diff mounts or you will get whine you may not like. Probably more whine than vibration.

If it is a race car, solid mount everything and buzz away.

Originally Posted by bigjae1976

Solid or poly motor mounts should be OK for most DD'ing. Its the trans mounts that really start to add a lot of buzzing and vibration.

Originally Posted by WaylonM3

I have the BW solid motors and trans mounts along with the BW solid race shifter. Best mod on my car thus far. Causes a lot of vibration (especially right after the install) but the whining sounds and noises that comes with this mod is phenomenal. I'd definitely recommend getting the shifter as well.

Originally Posted by pbonsalb

Those look miserable. Major compromises. Definitely a track car only thing. If your only street driving is to the track and you don’t really care about NVH at idle and lower rpm where it is noticeable because you are never at idle or low rpm because race car then go ahead. Solid motor and trans mounts are really dedicated racecar parts.

Thanks for the reply. I've also quoted one of your previous posts that mentioned the same.

Street driving is a bit more than just to the track. I have solid RSFBs, which didn't increase NVH, and a solid diff brace, which added whine but it's not noticeable (to me) so I would think solid diff mounts won't increase NVH any further.

It's the engine and trans mounts that I've been trying to find feedback on and I've included a few more comments from this thread. Street driving is generally in the 2000-4000 (or higher) RPM range. I'd expect noise at idle would be more noticeable but a raised idle may reduce/eliminate that.
What range do you class as "low rpm"?

I was also particularly interested in bigjae1976's comments that solid ending mounts should be fine for most street driving but it's the trans mounts that start to increase NVH, and also his feedback on the solid engine/trans mounts in his E46 M3 18 months later. I was also of the impression that engine and trans mounts solidity should be matched.

[pbonsalb]

Ask syt shadow since he has the Bimmerworld mounts on one car and new stock on another car. On my E36M3, I run Vorshlag 75D poly motor mounts with a 900 rpm idle speed and they are fine. On my E90M3 I tried Rogue motor mounts that are not as stiff as the Vorshlag and removed them because they added NVH that I considered objectionable but I did notice that if I held the idle at 800-900, they were fine. If you can get a custom tune with raised idle, I think stiffer mounts would be ok on the street. With the E36M3 I have tried a few trans mounts and found that I could not go as stiff on the trans mounts as on the motor mounts before NVH became intolerable for a driver, and I do run a higher idle speed on that car.

I recently bought some 80A trans mounts to try on the E90M3 and should have them on this weekend and will report how I like them. The stock trans mounts are really squishy even new ones, and that may be for a reason. I’ll find out soon.

I don’t think engine and trans mounts solidity should be matched. I think trans mounts should be softer than engine mounts. Except on a race car. Don’t worry - you will know right away if it is too much. I have over modded cars before to the point where I don’t want to drive them as much. I try to avoid that now.

[135]

Thanks! That's some really good information. It makes me think solid will be bearable on the street. Please post back your thoughts after you install the 80A trans mounts on your E90 M3.

[pbonsalb]

Solid motor or trans mounts would not be bearable on the street to me.

[///Mobbin]

I just picked up AKG 75D motor mounts and 95A transmission mounts and plan to install them in January. My car doesn't see much street time anymore though. To/from the office a few times a month to keep the battery charged and then to/from "local" tracks. Hoping my ~3 hour drive to COTA and a bit further to Cresson are still bearable, tbd.

If I was doing more street driving I would probably go Bimmerworld Group N or BFI StageII (85a) engine mounts and stock transmission mounts.

[XCUSE_M3]

Originally Posted by ///Mobbin

I just picked up AKG 75D motor mounts and 95A transmission mounts and plan to install them in January. My car doesn't see much street time anymore though. To/from the office a few times a month to keep the battery charged and then to/from "local" tracks. Hoping my ~3 hour drive to COTA and a bit further to Cresson are still bearable, tbd.

If I was doing more street driving I would probably go Bimmerworld Group N or BFI StageII (85a) engine mounts and stock transmission mounts.

Who do you run with at Cresson?

[135]

Originally Posted by pbonsalb

I recently bought some 80A trans mounts to try on the E90M3 and should have them on this weekend and will report how I like them. The stock trans mounts are really squishy even new ones, and that may be for a reason. IÂ’ll find out soon.

Did you end up installing the 80A trans mounts on your E90 on the weekend?

[pbonsalb]

Yes and I don’t like them at all. Fine at idle and up to a little before 2000. Very noticeable vibration from 2000-3000. Tapers off after that but still there. Would be great for a track car or a car that is street driven only occasionally to the track. But one if those mods that takes a lot away from comfortable daily driving since you cannot avoid going through 2000-3000 rpm range repeatedly in daily driving.

I will remove them. I don’t think poly “breaks in.” I may first try retorquing them since sometimes too much torque on trans mounts adds vibration and just the right torque does not.

[pbonsalb]

Running motor mounts that vibrate at idle and trans mounts that vibrate off idle is a good way to ruin a street car. If you actually drive the car, the vibration gets old fast. If you just drive it for an hour on the weekends and pretend it’s a race car and you are adding a whole lot of performance because the car now vibrates, then I guess it does not matter. If you really have a track car that is street legal just to get you to the track then it is also OK.

[bigjae1976]

Solid engine mounts aren't that bad. Lightweight flywheels are much worse. You get more exhaust noise.

My theory with solid trans mounts is the tranny is right under you so you're closer to the noise. If it were me, I would not get solid engine mounts if I didn't have another car to drive regularly. Otherwise, I'd do it unless you like to listen to the radio more than engine noise.