If there is one main gripe that comes with Mazdaspeed 3 ownership, it is the dreaded torque steer. At stock power levels it is a manageable problem. When you decide to turn up the boost, the problem becomes a little less manageable.
That is where James Barone Racing has you covered.
James Barone Racing offers their rear motor mount ($100) in 3 different durometer selections. 70 durometer (the softest), 80 durometer, and 88 durometer (the harshest). Each durometer selection has an accompanying NVH increase. NVH is an acronym for Noise, Vibration, and Harshness. The higher the durometer, the more NVH gets transmitted, in other words, the higher the NVH, the buzzier your ride will be. But before we discuss NVH, I feel like I am getting ahead of myself, you might be wondering why I would want to swap my stock RMM for one of these? Good question.
For stock power levels, the stock RMM is fine. Over time the mount will wear out and rip, but you can just replace it and keep rolling down the road. It will offer the best ride quality with the lowest NVH, after all it is what Mazda designed for comfort. Under load, it does deflect a bit. That deflection helps to create torque steer. Under spirited driving situations, it can also cause some missed shifts among other things. But as I said, at near stock power levels, all that is manageable.
When you turn up the boost, all of those small problems become exaggerated. You miss shifts, torque steer becomes very pronounced and that stock mount was not meant to put up with the abuse of higher power levels. That poor rubber mount gets worked hard and has been known to rip even after a fresh install of a new one. If you are going to increase the power, a good idea is to replace the rear motor mount with a better one.
Now back to the earlier conversation about durometer ratings and NVH. I decided to purchase a new RMM as future proofing, so of course I went with the 88 durometer mount. Why?
Installation was a simple remove and replace (you can watch the video in the install section of this site). The break-in, was anything but simple. First start-up and the car buzzed like the hive of a thousand angry bees. It buzzed everywhere. I found .50 cents that slid down the side of the seat because I heard the change rattling against each other. I almost regretted the purchase, but I knew from research that over time the buzzing would die down. It did after a few days and I was rewarded with a car that felt more alive.
I used to have a problem getting into first gear, no longer. All my shifts were now crisp and I missed shifts less. Torque steer had been dampened down to a level below even stock. It still buzzes now but anything above 3000 rpm and the buzz is gone. The neat thing for me is that I feel it in the seat of my pants when it revving hard now. There is something to be said about tactile feedback and the connection it makes between car and driver. I enjoy that sensation so much, I am considering changing the motor mounts too!
Long Term Update
I have had the same RMM in the car for a year now and I still enjoy it. The shifting is still precise and the buzz under 3000 rpm is still there. But with the boost increase I am running now (18 psi) I don’t think the stock RMM would have lasted much longer. It was already ripping when I replaced it. I wouldn’t call this an absolutely necessary mod, but it should be high on your list if you are modding a Mazdaspeed 3.
James Barone Racing Rear Motor Mount