Sneak Peek at an Upcoming Transmission Motor Mount

Here is a treat for GEN3 (2014+) Mazda 3 owners!

We are in the process of designing and producing a CorkSport Transmission Motor Mount, (TMM), to reduce the excessive engine movement present from the factory. Buckle up as we go through a sneak peek at some features and go through the design process and decisions that all serve to give you a better mount in the end.

When approaching this project we sought out to improve the performance of the GEN3 Mazda 3 without sacrificing drivability or OEM fitment. Stiffer motor mounts are a great way to improve throttle response, improve shift feel, and reduce wheel hop by reducing the total amount of engine movement but they can hugely increase NVH (noise, vibration, and harshness). As such, there is a balancing act between finding an acceptable level of NVH for the performance gains you get.

In a typical front wheel drive car the engine is mounted in a transverse matter, that is, the engine is parallel to the axle centerline. So when the engine tries to turn the wheels, the force to do so tries to make the engine rotate in the opposite direction. Motor mounts resist this motion of the engine.

Initially, we wanted to change the orientation of the factory mount for the Mazda3 to use the polyurethane bushings in the most optimal way possible as the bushings function best when they are parallel to the axis of rotation. Doing so proved to be difficult as we were effectively creating a new pivot point in the system.

Going through this design, we also realized that overall size was becoming a problem as different transmissions have varying heights. Since this mount sits right above the transmission, this was a vital thing to keep in mind. So for our 2.5L manual Mazda 3, we had a good amount of room below the mount, but it needed to go on a serious diet to fit an automatic model. This meant moving to a drastically smaller bushing which likely would have increased NVH, only using the mount for manual models, or using a custom bracket for each different transmission & model. Check out down below for one of the early (and ugly) designs.

So we went back to the drawing board. We decided to move forward with a design similar to the OE design. Doing so allowed for a smaller mount, easier manufacturing, and a significantly wider applicable model range. This includes all 2014-2016 Mazda 3, all 2014-2016 Mazda 6, and 2013-2016 CX-5 (we have not confirmed the 2017+ models years yet, but there’s a good chance this will be compatible).

Even though we went to a similar design to OE do not assume it’s the same thing. The CorkSport mount has the same diameter bushing as the OE mount; however, the OE mount does not utilize all the available space. This means that in addition to the stiffer polyurethane material, there is simply more material to resist the engine’s movement.

The CorkSport TMM utilizes billet aluminum for the main body of the mount with stainless steel plates for the washers and the angled section of the mount. This provides a more attractive and lighter mount than the OE offering while retaining the same strength and fitment of OE. Check out the picture down below for a look at one of our 3D printed prototype test fits.

We just received our first functional prototypes for further fitment and testing since 3D printed plastic parts don’t support an engine & transmission very well. With these samples, we can determine exactly how stiff to make the polyurethane and finalize the best possible design for you. During our test fit, we even noticed some deterioration of the OE mount.

This OE mount came off of the CorkSport Mazda 3 racecar. While it does not have many miles, they have all been racing miles that are very hard on all vehicle components. Check out the image down below to see a comparison between the used mount (left), a new mount (center), and the CorkSport prototype TMM (right). It’s interesting that Mazda has made some changes to their OE mount in the last few years. What you can’t see very well is that the racecar’s mount has areas where the rubber is starting to separate from the metal center section of the mount. There are even a few small tears forming on some of the inner bushing surfaces.

These signs of wear are encouraging to us at CS since this means we are helping to solve a potential problem facing 2014+ Mazda3 owners. As such we could not wait to get the TMM on a car for testing. Fitment is great so far, and we were even able to overcome some minor manufacturing errors. The first test for the mount was with the CorkSport Mazda 3 racecar at the 25 hours of Thunderhill. This event is an endurance race that runs for 25 hours straight.

The Mazda3 completed 613 laps during this time covering over 1800 hard miles. This is a torture test for any part, and I’m happy to report that the CorkSport TMM passed with flying colors. The drivers liked the mount and Derrick (who owns the car) reported greatly reduced slop in the transmission when shifting. Here is what the mount looked like after the 25-hour long race:

Aside from being very dirty and having a few scratches where it was bolted down, the mount had no issues and was still in good working condition. It already has a new home in a daily driven Mazda 3 to get even more testing done. Initial impressions are good, but we will look to decrease NVH as much as possible before any of you get your hands on it. Look for the CorkSport 2014+ Mazda 3 Transmission Motor Mount in the next few months.

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