So I got some solid motor mounts for my car. They are about 1/2" taller than the stock ones. Stock mounts are relatively fresh. I asked about this and the reply was that over 10-15 years stock mounts will mash down. I don't think this really applies to me.
My questions are,
Does anyone know how tall a stock mount is?
If these mounts are actually taller, how much does that hurt?
-I am worried it will change the driveline angle, and cause extra wear to the u-joints, etc. Also, it will raise the CG of the car, which no one wants.
SOlid mounts are a bad idea, unless of course, the prize for coming in First Place is $100,00.00. Under those circumstances, I suppose even I could tolerate solid engine mounts for 40-60 minutes.
It is 1200 for tires, a little bit for brakes, and a couple of hundred in other gift certificates. Plus, you get a picture with the trophy girls. I don't really drive the car though, except for to and from the track, so It should be worth it. If not, nothing and hour or so can't fix.
Also, they are not exactly solid, more of a delrin type material.
Last edited by bionicbelly; 03-09-2017 at 01:22 PM.
I'm running these and don't have any issues - http://www.vibra-technics.com/bmw/z3..._engine_mount_
Still rubber, but a very stiff version.
2001 Steel Gray MCoupe - 147,000 miles and owned since new. MCS 2WNR suspension, Hotchkiss swaybar, poly bushings all around, cat delete headers with custom tune, 3.73 LSD, and Clownshoe Motorsports rear subframe reinforcement.
2014 Porsche Cayman S / 2022 BMW X3M Competition / 2020 Ram Rebel
Any idea how tall they are?
20150612_142011.jpg 20150426_115048_resized.jpg
A couple races ago, we sheared a stock mount and fixed it with a ratchet strap (you do what you have to do mid-race). That broke, so we cut some chain off our trailer and that did the trick. We got the car back to the shop and our machine engineer teammate fab'd up some solid aluminum mounts (photo #1). We backed those up with some turnbuckles mounted through frame and tied to top of motor (photo #2).
Solid mounts make my teeth hurt. I think I'd love them if I wore a mouth guard. Forget about it on the street. Everything vibrates and buzzes, and not in a way you think would be enjoyable. Usually after a long session I just have to pee.
Nathan in Denver
1999 M Roadster, VFE V3 S/C, Randy Forbes Reinforced, Hardtop, H&R/Bilstein, Apex PS-7, Supersprint
1999 Z3 2.8 Coupe, Headers, 3.46, Manual Swap, H&R/Koni, M Geometry/Brakes, M54B30 Manifold, Style 42
Ill go ahead and take a stab at actually answering your question instead of discussing solid mounts. I had solid mounts in my old Stealth R/T Twin Turbo, felt fine. I don't care if my sports cars feel a little stiff and bumpy.
I don't think 1/2" an inch should hurt. I just replaced my mounts with stock mounts and the engine has quite a bit of "wiggle" room when replacing things. It could potentially put a little more stress on your transmission mounts, that's all I can really think of. I the drive shaft has u-joints to take care of any angle issues. My engine was probably sitting 1/2" low with my old mounts and it didn't hurt anything else down the line.
A nod to Nathan for confirming all that I alluded to. And taking a little more of a stab than venom, this is what I have:
Recently removed mounts from an 09/98 build Coupe: 66.79 mm
Brand new BMW sourced (11 81 2 283 798 (always keep a few in stock): 68.99 mm
With a half-inch gain in height, I'd be more concerned about the throttle body (or manifold; I'm not near as familiar with non M models...) hitting the underside of the hood than about any affect on driveline angle and associated wear.
Thanks!
This actually makes me feel better. 68.99 mm=2.717 in. My old mounts were 64.21 mm, and my new ones were 73.15 mm. I guess it was closer to a 1/4 inch difference.
There seems to be room enough that the manifold/valve cover won't hit. I did start it up, and no, I would not want these on a daily, but it isn't that bad. REALLY looking forward to see how they work on track.
Make sure you are comparing apples. An inline 6 cyl is naturally balanced, as it's cousin the V-12 (Jaguar called it a double-6). 4 cylinders are not; the inertial loads of the differing piston accelerations cause them to hop up and down. You can probably get away with solid mounts on a 6cyl where a 4cyl will be blurred vision unbearable.
/.randy
For my own curiosity, what is the benefit of solid mounts? Is it just durability on track, or something more?
I recently put the 95A mounts here: https://www.revshift.com/product-p/pmm-r36.htm
in my car... Really didn't add a lot of NVH. Feels pretty solid.
96 320i Touring
98 Z3 2.8 Roadster
01 PY M Coupe
96 Z3 1.9 - DASC
95 318ti Clubsport
94 Miata M-Edition
13 smart fortwo
Yep
There was an increase at idle, but it calmed right down once the revs went up.
- - - Updated - - -
Better shifting, better response, better ability to feel what the car is doing , and how the right foot is affecting the car during cornering. That sort of thing. That is what I am hoping anyway.
I autox my cars so I personally like my poly tranny mounts. Engine mount I've never tried them.
2001 Steel Gray MCoupe - 147,000 miles and owned since new. MCS 2WNR suspension, Hotchkiss swaybar, poly bushings all around, cat delete headers with custom tune, 3.73 LSD, and Clownshoe Motorsports rear subframe reinforcement.
2014 Porsche Cayman S / 2022 BMW X3M Competition / 2020 Ram Rebel
So, a little update. Drove from Des Moines to the NCM Motorsports park this weekend. I do not regret these bushings at all. I feel like shifting is better, overall feel is better, and on the highway, I do not even notice any extra vibrations. There are vibrations at lower RPM's, and you can fell some shudder when taking off from a stop, but for what I do with the car, it is insignificant.
I had some poly inserts on my Vibe. They didn't bug me much, but my mom hated them and I felt self conscious when anyone else rode with me.
In contrast, one of the motor mounts on the Z3 opted to rip in half instead of detaching from the crossmember even though it was unbolted when I lowered the member. I noticed absolutely no change in vibrations and it still ran smooth as butter. When the new ones arrived the next week and I put them in, the only thing that changed was my anxiety about them.
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