Thx for the great review! +rep

Thanks Raul for taking the time out to try this out. I pm'd you but I'll post it here too since everyone should hear/see it. When I did the 75A (stiffer than yours) mount in my own car (350Z), I literally thought we had forgotten to reconnect my exhaust! I've got a build motor, Crawford headers, test pipes and a titanium exhaust. Everything inside the car resonated and was much louder. The rear glass had a noticeable resonance at the 2500-4000 rpm point. You even felt it in the steering wheel. This was done on a Saturday afternoon. I spoke to the engineer on it and he assured me to just keep driving it and it would settle in, so I did. It made a world of difference. By the following Wednesday, I had done around 350 miles in the car, a mix of highway and alot of backroad (so lots of shifting, accel/decel) and it had settled in perfectly. It was still a deeper sound in the cabin but none of the resonance was there.

If you've got some time to do some more miles, give it a go and let me know. I'll also talk internally and see what we can do about a lower durometer as well.

Thanks again!

Interesting. So let's assume RCZ racks up a few hundred miles quickly and confirms this. How long before these go into production and are available for purchase?

I'm hoping that things settle in as I'd love to firm up the shifting action.

Hopefully it will, and I am sure RCZ will report back after a week of driving.
Thanks for doing this RCZ, hopefully now with one on a car we can dial everything in to get perfection for this part.

I mentioned this a while back when this was first talked about. I think you will find a lot of your problems are from using two different bushing materials. your motor mounts (most likely softer bushing) are fighting your trans mount bushing which is now much firmer.

You have to look as the motor and trans as one piece since they are solidly bolted together. And since this is the case you cannot use two different bushing materials because they will fight each other, which might be why the Z1 mount is 'loosening up" when in fact it is wearing out prematurely from fighting the vibrations that the motor mounts are allowing.

I learned all this the hard way with suspension bushings and it took me 3-4 bushing sets to realize you have to change out all the bushings that are affected to the same material other wise they are just going to fight each other.

So I feel that until you get some motor mount bushings that are of the same stiffness you will continue to have this problem.

Good point.

The factory motor mounts are MUCH stiffer than the factory transmission mount. By increasing the durometer on the transmission we're actually better balancing things than even Nissan does from the factory. We tested the factory 370Z motor mounts extensively as we had also planned to possibly release a urethane version down the road. We decided for the time being that such a mount would not be beneficial, and if a mount is to be developed, a solid one would be the best solution. That is still in the design phase though, and not something we have any immediate plans for (since there are still so few cars out there). FWIW, this is exactly the same case with the 350Z. The motor mounts were significantly stiffer than the transmission mount.

Urethane settles....that is the nature of a product that has some level of give to it, and particularly one with a 110 lbs transmission bolted to it. The mounts we're using on the 350Z's have been R&D for quite a while before I even tested it on my car own car. I've inspected the mounts personally after months of use, track days, and no wearing is taking place. If any was present, I never would have installed it on my own car, and I'd certainly never sell it. I frankly don't need the money that badly to bother dealing with stuff that's not going to make our customers happy.

We've got a few other ideas on how to even further reduce vibrations and I'll be looking over those in more depth as well

So RCZ, did you install the Comfort edition, or the Race edition?

Comfort.

ouch.

Raul, thanks for the GREAT review. And as usual, for being a willing test bed +1 rep :tup:

You're all welcome. I will definitely keep this updated throughout the following couple of weeks. Either I'm getting used to it or the vibration is starting to ease a little already.

^ that's great news for the rest of us Raul, thanks :tup:

That is Great News! Thanks for being the guinea pig RCZ. Ha..

How are the SPC front and rear camber arms holding up...are you still happy with the performance?