[Dimma]

Hi Guys,



Anyone of you who knows about a transmission mount which is stiffer then the Porsche one but not as stiff as a solid one ? So a mount for street-sport use instead of a full racing car ? I mounted the solid one yesterday and though it does solve my problems with wobbling or / and flipping out of 3th gear it gave me a screaming gearbox ( the light version ) in return. So I'm looking for the best of both worlds ....



Anyone ?



Thanks !



Regards, Frank

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[flash]

i've never seen one. the OEM mount is a pretty crappy design. i think the best you could do would be a link bar. i'm planning on adding one to my car and will post shots soon.

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[Dimma]

Yes, I did it !



I stiffened up a new transmission mount and it works great ( for me at least ).



What I had :



With my old mount the car wobbled very ugly when engaging the ( Spec stage 3+ ) clutch, the back end dribbled when shifting down to 4th and even worth when shifting down to 3rd. On the track it even popped out of 3th gear when shifting down under heavy breaking. Further more the Alu flywheel made a lot of noise from 2000 to 3000 rpm.



What I did :



First I bought and mounted a solid mount ; that did work for the wobbling when engaging the clutch and for the dribbling while downshifting but what I got in return was a very irritating scream from the gearbox from 80 on to 200 + and the noise from the Alu flywheel got even more intens. So a solid mount is too much for me.



Then I bought a new rubber from the Porsche dealer ( only 56 Euro's ! ) and started by filling up the empty spaces in the rubber with a ( rather hard ) windshield sealant. Then I machined a piece of Alu into a triangle shaped plate to fill up the space between the 'cage' and the rubber. Now the rubber will, instead of leaning against 2 small strips of rubber on the upper part of the mount, have the full size of the rubber to push against under load.



After giving the sealant time to harden I mounted the new mount and it works out just fine for me ! No more wobbling when engaging, no more dribbling when shifting down, no more noise from the transmission and the noise of the Alu flywheel is not completely gone, but better then it has ever been.



Total cost : 56 Euros for the mount, 20 Euros to have the Alu machined, 10 Euro for the sealant and that's about it !



a very good modification for your car ! the back end of the car really benefits !

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[Cloud9...68]

Interesting... It sounds like you came up with a very good solution for your problem, but I can't say I've ever noticed the symptoms you describe. Do you think the extra torque from your turbo was resonsible for the wobbling and "dribbling" you were experiencing? Or was it likely just a worn-out transmission mount, or a combination of both?

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[flash]

wobbling and dribbling - are we sure we aren't just at the pub?

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[Dimma]

Hi guys,



Sorry if I use the incorrect words to discribe what it feels like ; that is hard enough in your own language let alone in a foreign one ....



The car has spent some 15 years as a normal road car also doing at least 2 or 3 trackdays a year ; that does tend to wear out things, doesn't it ? and it's a genuine CS also.



The gearbox mount was well worn when it came from under the car but that will not have been from the few Turbo miles I did. So it was up for replacement anyway. What did surpirise me was that when I mounted the new one unmodified ( which was by the way different / upgraded from the one under my car ; Porsche tried to stiffen it a bit by putting an extra plate in the middle of the mount ) it still showed the same behaviour as with the worn one ; Ok a little less but not as much as I had hoped for ... and by far not as much as I needed !



If you don't experience ( yet ) what I have you now do know what to do whenever that time comes <img src="/forum/images/smilies/968/wink.png" class="smilie" alt="" />



Going to the pub now <img src="/forum/images/smilies/968/smile.png" class="smilie" alt="" />

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[savvas968]

try some polyurethene sealand used for bus front windscreen of shore 60 to 70 grade.

fill the voids and pour on top top and sides inside the x member.

Allow to cure for 36 hours. Best of both worlds.

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[flash]

one of the things i am currently working on is a sort of panhard rod for our transaxle. that will hold the box centered in the car. it won't take me long to get this out there either. i have had the design idea done for months, but not had the time to put the car in the air to finish it up. since i get the car back this week, and it will be up in the air for a few days, i'll get a chance to finish up a few of these kinds of projects, and get some new stuff out there.

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[MB968]

I agree with Savvas. I've use a window mount urethane, 3M part # 08609 to do engine and tranny mounts. Its ~65 durometer and can usually get it in a day or so from your local NAPA dealer. It does have a specified 48 hours cure time, which I've found to be even longer when filling large cavities (wait 3 days and you should be OK). 3M part # 08613 (about the same mechanical properties as the 08609) has a shorter, 24hr cure time, but is much more viscous, and can be difficult to fill voids without entrapping a lot of air.



I did all 4 engine/tranny mounts on my Mazda 2.5l, and it transmitted a little more noise/vibration, but not bad at all for a DD/weekend track car.

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