: REVSHIFT poly hardness selections for minimizing NVH increase

03-04-13, 12:11 PM
Good day, all. I am about to place an order from RS for everything they have currently for the V. Below is the parts list, along with the hardness level that I am leaning towards for each. I would like some feedback on my choices of hardness, given the type of driving that I do mostly. So far, my car has been strictly a daily driver, but I am considering some upcoming auto cross days. I would like to stiffen the car up, but at the same time I don't want to increase NVH horribly. So my goal is to use the hard poly for areas where it won't contribute as much to NVH, and the softer poly where it would make a noticeable increase. In the list below, I have taken my best guess at pairing hard poly with parts that don't affect NVH, and soft poly with those that do. Does my matching make sense for each part? Do any of my "hard" selections contribute noticeably to NVH, or could I get away with upgradeing from soft to hard for any of my "soft" selections?

Diff mount - hard
Rear cradle - soft
Rear trailing arm - soft
Upper control arm - soft
Motor mounts - soft
Trans mount insert - hard
Flex disc coupler - hard

I appreciate the opinions!

OneFast V
03-04-13, 01:30 PM
diff mount will definitely contribute to NVH as would transmount insert. They don't make the flex couple with the hard durometer poly. I would go with the hard durometer poly for the trialing arm bushings and UCA bushings and nothing else is NVH is a big concern. the "softer" poly is already much stiffer then the OEM rubber.

03-04-13, 02:51 PM
We only make the coupler with the harder 95A polyurethane but we just color the bushings blue because it looks better than red. We can actually make the polyurethane any color we want. The trans mount insert is only available in the softer 80A.

If you don't want nvh then stick with 80A motor mounts. That is the most important thing here. You most likely are going to see only minor differences in nvh with the rear end bushings.

03-04-13, 03:15 PM
The simple answer is 95A everywhere except the transmission mount (which you don't have a choice on) and the motor mounts.

03-04-13, 08:27 PM
I agree with ^^^^^^^