Motor and Transmission Mount Installation - May 26, 2008
I decided to install stiffer motor mounts and transmission mount on the car to try to reduce the loss of power through the drivetrain. Stiffer mounts allow for more energy to be transferred to the wheels instead of being wasted in twisting the engine in relation to the chassis. I used Project Silvia Motor Mounts and the Peak Performance Race Transmission Mount.
- I installed the transmission mount first. To take off the stock mount, I removed the two bolts that hold the mount to the transmission.
- Then, I supported the back of the transmission with a stand and removed the four bolts that hold the transmission crossmember to the chassis.
- With the crossmember out, I unbolted the stock mount from the crossmember and attached the Peak Performance unit using the two supplied bolts.
- I bolted the crossmember back onto the chassis and then attached the mount to the transmission using the two supplied bolts.
- The peak performance transmission mount does not have a spot to attach the catalytic converter bracket like what is done with the stock transmission mount. Therefore, I decided to weld the bracket onto the crossmember after installing the motor mounts.
- To take out the old motor mounts, I first removed the top and bottom nut on each mount that hold them in place. I removed the nut that holds the heat shield in place on the left mount. (The actual heat shield broke off a while ago so I just removed the small piece that was still bolted to the mount). On the right side mount, I removed the braket that the wiring harness should probably be attached to. Mine was not attached to the bracket.
- I placed a 2x4 across the oil pan and slowly jacked up the engine from the bottom until I could slide out the old motor mounts.
- I put in the new right side mount first. I took out the two bolts that connect the upper and lower part of the mount together (bolts that go through the bushings) and installed the lower and upper parts separately on the car. I left the nuts loose for later adjustment.
- I did the same for the left side mount.
- Then, I slowly lowered the engine until the upper and lower parts of the mounts lined up relatively well. I put the two bolts on each side through the mounts using some persuasion.
- I lowered the engine completely down and tightened all of the fasteners.
- With the engine and transmission mounts installed, I had to fabricate a mount for the catalytic converter.
- I took off the bracket that was connected to the stock transmission mount and bolted it to the bracket that extends off the catalytic converter. After grinding the paint off the back of the transmission mount, I welded the bracket that used to be on the stock transmission mount to the crossmember. Finally, I sprayed the crossmember with black paint. This setup is essentially that same as having the catalytic converter connected to the transmission mount since the engine/transmission won't be moving much with the new mounts.
The first picture shows the right side mount installed, and the second picture shows the left side mount.
The process sounds easy from the steps I outlined above, but it was actually pretty time consuming and required a lot of patience because of the tight space around the mounts. It also required some small wrenches to get into those tight areas, so I'm glad I ended up doing it at my dad's shop.
The car feels much more solid with the new mounts. There is very little "torque feel" when getting on the gas hard or just revving the engine since the engine moves with the chassis.
The engine sits in just about exactly the same position as with the stock mounts, so strut bar clearance wasn't an issue (at least not more of an issue than it already was with stock mounts). However, engine movement is greatly reduced so there should be less rubbing of the valve cover and injector wiring on the strut bar.
The ride comfort of the car is pretty horrible with the new mounts. Everything vibrates and rattles inside the car, especially below 1200-ish RPM. But the performance gain is well worth the sacrifice in comfort.