alpine003

I've always wondered if this was true. I've read conflicting info.

I have the turbo mounts and can't feel any difference compared to my non turbo mounts.

laz74

My guess is the Turbo mounts have more rubber than the Carrera mounts, but they're still hydraulic.

What about the GT3 - does it use Turbo or Carrera mounts?

SSST

The stock 996 Turbo mounts are definitely hydraulic. I cut one of mine open after I replaced them with the X73 mounts. The X73 mounts are visually identical to the stock mounts, but are a lot stiffer. I had assumed they are also hydraulic, but I'm not cutting one open to find out.

alpine003

Thanks for the verification. Bummer as I thought I had "upgraded" by getting the turbo ones.

Did you feel any difference between your original stock mounts and the x73 mounts?

SSST

Huge positive difference in handling, smoother shifts, and quicker off the line. Just by holding the motor in place better, less energy is lost from the motor torquing on it's mounts. No noticeable difference in vibration, ride, or noise.

I'm not sure how much of that was worn stock mounts and how much is stiffer X73 mounts. However, I chould hold the old mount in my hand and easily flex the threaded shaft around in the mount. I couldn't budge the shaft on the X73 mount.

BTW. I installed the mounts 2 weeks before the shocks and springs, so I got a very good read on the difference just the motor mounts made. It was significant.

alpine003

Bump. Any updates on if it's still holding up good?

One thing I'm still not 100% clear on is if there is a potential for the rubber cup portion to decouple from the metal housing and shoot up since the metal cap is no longer there.

Also important to note is to get 80A rated Polyurethane as their are several designations of which the two most used are A and D ratings. Different stiffness even though it's the same number depending on if it has the A or D designation.



Another source to get varying durometer levels of Polyurethane is McMaster. http://www.mcmaster.com/

Thinking of going this route soon.

laz74

Yes, holding up very well. I've done a couple thousand miles and several autocrosses since installing. I'd like to go stiffer, so I'm working on another set using slightly harder 90A urethane.

The metal cup is not structural - it's only purpose is to protect the pre-existing rubber enclosure for the hydraulic fluid, which I remove.

It's also important to note that older mounts sag, and so it's necessary to make a jig to relocate the stud relative to the housing before filling. I took measurements from a brand new OEM mount and will construct and utilize this jig for my next set of mounts, ensuring perfect fitment.

Hardback

The original mounts allow the motor to sag. When I installed RS mounts I realized the engine was lifted higher in the chassis. The RS mounts are not great at keeping a low center of gravity as a result. (lowering the car helps obvuiously) So, your mod actually keeps the height of the engine as low as stock but stiffens the movement of the motor. Pretty cool.

laz74

Hardback, thanks for confirming that.

masitr

Great Info. Do you know roughly what the height difference is?

MiamiC70

I am about to pull trigger on RSS mounts for my 40th AE riding on x74 suspension

bornrich

I have the RSS mounts in my C2 and really like them. That being said if the Function First mount would have been available when I did mine I would have bought those. Based on the quality of their trans mount I think their engine mounts would be a good option.