Urethane Transmission Mount

RCZ

Here's the review, just in case people dont know where to find the journals.

OK, so here's the review as promised.

Installation:

It was extremely easy. Its 6 bolts and its done. Very easy access, doesn't require any special tools, however you do need to find a way to support the transmission so it doesn't sag when you take off the mount.

This is what you are looking for under the car. Its right by where the driveshaft starts:



Support the transmission somehow. We used this guy, but you can use whatever as long as its sturdy enough to hold up the weight:


Remove the bolts:


Stock Mount:



Side by side comparisons.



Removed:


Z1 Mount on. Make sure the "arrow point" is pointing towards the back of the car:



After that, just put the bolts back in and your are done.


Thoughts:

Alright, so did it make a big difference? Absolutely. On the pro side, it made shifts much more positive. Shifting feels very consistent in every situation. It feels crisper and more exact when you put it into gear. You get this sensation like no matter what you are doing; accelerating or decelerating, the shifter is attached to something that is completely solid instead of something that has some give to it. As expected, that off-throttle jerking in low gears has been reduced. Instead of getting a sort of reverberating stop-go jerkiness that you get with the stock mount, you get this "load, unload, over" type of a feeling. Its hard to describe. Think of it this way... with the stock one it feels like the transmission is moving back and forth as it loads with the engine. With the hardened mount it feels like the whole car is a solid piece being acted on by the loading/unloading of the engine. You still feel it jerk, but it does it less and less abruptly.

Now the problem is this... and you folks knew there was a problem coming.

We know our engine and tranny are notoriously coarse as we go up in the RPMS, well guess what...you can hear and feel EVERYTHING. You can hear the synchros speeding up and slowing down when you put the clutch in and out. You can hear every little engine sound, clutch sound and chassis sound X100. Sounds like I have straight cut gears inside the car. If that wasn't bad enough, as you can imagine, huge amounts of vibration is transferred into the cabin. When I got home after the install, my whole body had that tingling sensation you get when you hold on to something tha'ts vibrating for too long. Just revving the car in neutral shakes you like a massage chair. My friend was joking that its a nice massage mod and that maybe girls would really love it.

I talked to Z1 and they said to give it a few hundred miles to let it bed in because it should get a little better. I drove around 100 miles this weekend and it has not really improved much. I am going to leave it in for the week and see if there is any improvement in NVH levels. It feels so good for shifting that I really don't want to let this one die. Please keep in mind that it is a product in development and it still needs to be altered a bit before production. I think if we made it less stiff it would get rid of a lot of the NVH, but it will also feel more like the stock one.

I think this would be excellent on a dedicated race car, but as it is right now, I don't feel the level of NVH is acceptable for a street driven car. Perhaps what we need are shifter and differential bushings + a softer version of the transmission mount. I am not happy that the side effects were so bad since shifting feels excellent. Way more composed and consistent than the stock one. Z1 said they would look into lowering the stiffness of the bushing if it's necessary. He will probably chime in and tell us what the plan is.