[modernbeat]

So, I had a member here point us to this thread with some questions about the mounts and legitimate concerns about their use in their daily driver. Here's what I wrote back to him.

For a daily driver with stock power levels there is not an easy solution. If a performance motor mount is doing what it should be doing (limiting movement) you WILL have more vibration passed into the tub. The stiffer the mount, the more vibration will be passed. If you find that you need to keep the engine from rolling over and causing the money-shift on track, then you need stiffer engine mounts. More power and more grip will exacerbate the situation, and you will find that stiffer mounts are required to keep you from missing shifts, having the shifter bind up, or shifting into the wrong gear (and blowing up an engine - the money shift).

We have looked at a LOT of other designs and still feel our style is the best. We don't rely on metal bonded to poly, which ends up tearing. We don't have a true bolt-through design, which requires massive torque to keep it in place. Our mount is secured to the subframe separately from the bolt that holds the polyurethane bushing and engine. And what was mentioned in that thread about over torquing is true. If you over tighten and preload the bushing, you have made the mount stiffer and it will pass more vibrations. Tightening it up just enough to capture the bushing is the right way to install ours. Tightening it until the bushing bulges is NOT going to make you happy.

There was also a mention of our mounts breaking. They did. The previous design was susceptible to damage if it was asked to bend, which is what happens when someone drops the transmission without loosening the engine mounts. I spoke to many owners that broke a stud and kept a database of issues. In every case they had either had a recent wreck (causing a shearing motion to the mount), or more commonly, had serviced the transmission or clutch without loosening the engine mounts (like putting a huge cheater bar over the stud and then bending it over). When the SCCA changed their rules that stipulated the ratio of metal in replacement mounts we took that opportunity to make the mount stronger with a shorter top stud. Since then they have been problem free and seem to even stand up to the dropped-transmission issue.

The bottom line is that if fresh, stock mounts are not preventing shifting problems for you, then you should move to a stiffer engine mount. If that's is not enough, then add a stiffer transmission mount. And if that is not enough, move to a solid engine mount and the stiffer transmission mounts. Understand though, that with every iteration they will pass a little more vibration into the tub. With just poly engine mounts, it's a livable amount when installed right. With engine and transmission mounts, you most likely have performance tires, dampers and upgraded spring rates, so the change in vibration will most likely be lost in the changes that those other components make.