Vibration from poly mounts at high speed? (70+ mph)
 

Is this possible for the car to shake because of the poly mounts at speeds 70-110mph?

The car is at the shop and the mechanic replaced tie rods but he stated that vibration is still present. We can't rule out the mounts because I have poly filled.

I have replaced the wheels, tires, I have new flex discs and I'll replace the tranny mount this weekend to see if that will help anything.

I also have a weird vibration in park at 1800-2000rpm, so I wonder if that's tied into this. Research shows it might be the torque converter...

Does the car feel like its swaying? Check the rear bushings.
Does it vibrate on throttle or in neutral while rolling at speed?

Lol..you just answered your own question

It's def the mounts, I drove it fast on the highway and they vibrate a bit.

But it's definitely not as bas as it used to be before the service he performed (bearings, tie rods, balance tires, alignment) the car's a lot better. Don't get solid mounts!

Shouldn't you have solid trans mount if you have solid motor mount?

I just replaced my mounts about 6 months ago with OEM Lemforder, but was thinking about using solid poly mounts next time around.
This thread is definitely making me question that plan - seriously don't want any vibration.

You'll definitely feel more of a vibration with poly mounts. The poly is stiffer than the oem rubber mounts and on top of that, you don't have the fluid anymore.

Countdown until the solid poly mount manufacturer (East Coast Euro?) chimes in.
10, 9, 8, ...

I warned about this when you wanted them ,what you expect from solid mounts

Replacing OEM mounts is a crappy job to say the least but they are so cheap and vibration free...

The OP is not using our product. He is using a stock mount filled with polyurethane. Ours is designed from scratch to achieve our goals and minimize vibration.

The mounts that he is using were made by me - just OEM Poly Filled, 80A... made and sold for high power cars that eat mounts, little care was given to vibration as the customers they are made for and marketed to, don't care about vibration. A few of our cars can bust a set of mounts in one dyno session... (650+ whp cars). I have bought and installed a set of the ECE mounts and they are the best of both worlds.... we have put in heavy testing on the shop car, and they don't flex much at all, and are much smoother than the ones I took out (mine).

Big shout out to ECE for coming up with a quality solution!! :y

Thanks

Dave

Some good respect here between contributors to the AMG scene :y

Thank you for the kind words! Great to hear they are performing well 👍

So to make it clear: My car had other underlying issues with the suspension and bearings that lead to a different vibration at high speed, so really I never even had a clean chance to experience what the poly mounts should actually feel like.

I made this post before I picked my car up from the shop. After I picked it up I drove it on the highway post repairs and it was a night and day difference. The vibration from the poly mounts is barely an issue at this point, I had a much worse problem going on. Luckily my mechanic was able to get to the bottom of it.

At this point I'm not even sure i want real mounts again, I love the responsiveness of these mounts.

Ahmad's mounts are the future though. Curious to see how the tranny mount would perform and what it does for day to day driving. It's next on my list of things I want to install.

Like mentioned these were poly filled, not the fabricated ones.

The issue turned out to be something other than the mounts, they perform at an acceptable level.

So what was the issue?

Needed new tie rods, to tighten the bearings, and a new alignment.

I recently took my car to the dealer after chasing down a similar vibration that never got solved with balancing. They suggested that my front wheel bearings needed "adjusted" and re-lubed.

I didn't even know the wheel bearings were a serviceable part on this car. Rebuild kits are cheap. I wouldve done this my self but had the car in for a bunch of maintenance items and they covered the cost of the wheel bearing adjustment. Seems pretty simple though.