Upgrading to a stronger motor mount with urethane inserts is a popular upgrade for many car owners that have increased the power output of their vehicle. Most manufacturers of these high performance motor mounts offer several different types of urethane so that you can select the best choice for your application.
The different urethanes have varying durometer levels, often ranging from 62a to 94a. Is the number related to performance of the mount... bigger is better? Not necessarily.
The first thing to note is that no urethane is stronger or is going to outlast any of the other options. A higher durometer mount only increases the stiffness of the mount. This translates into NVH (noise, vibration, and harshness). NVH can range from a minor annoyance to the driver and/or their passengers to being so severe that it causes issues with the sensors in the vehicle. For example, Honda does not use 94a urethane on their track cars because of sensor issues due to the extreme vibrations.
We reached out to Hasport, the most trusted name for performance motors mounts, for their recommendations. Here is what they had to say:
62a - "Street" - Recommended for street cars that may see occasional track use
70a - "Race" - Recommended for heavy autocross or road racing
88a - "Extreme Race" - Recommended for weekend drag racing
94a - "Most Extreme Race" - Recommended for dedicated drag race cars only
If you have any questions about which urethane is best for your application, please feel free to Contact Us. We are always happy to assist!