Here's something that ought to be made out of Al

[Randy Webb]

Accurate wts. in lbs.

915 style transmission support bare (bare), w/shim 3.7
915 style trans.support complete w/ rubber mounts, through bolts, etc. 6.0

Anybody know how much the 964 style mount weighs? It's Al.

[Porschekid962]

why not get crazy and build the trans case out of rfcc??? mclaren is using that this year in F1. pretty insane stuff, maybe after i win the lottery.

[Jim Sims]

If the design of a part is governed by stiffness (flexing and deflecting under load) then switching from steel to aluminum may not be warranted as although aluminum is about 1/3 the weight of steel it is also only 1/3 as stiff. One may be better off optimizing the steel part but this can drive up manufacturing costs. There are a lot of tradeoffs both technical and economic. Cheers, Jim

[Randy Webb]

Right, Jim. Then there's Ti. But ever since I saw a 964 version on eBay it occurred to me that PAG already did the analysis needed re flexure.

Someday I may try to modify the 964 Al piece. It is not a huge amount of wt. and is in about the best possible spot to have wt. but....

[Jim Sims]

Ti's still only 60% the stiffness of steel; I know of an application (non-automotive) where substituting Ti for steel resulted in performance degradation due to the stiffness issue. Jim

[SpeedracerIndy]

Here's on on ebay. Only $55: http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=33733&item=2481312897&rd=1

[MT912RS]

Crummy pic.

[KTL]

Try one off of a 87-89 G50. It's aluminum/alloy too. Problem is, the mounts are not removable and it's beefy. So it's probably heavier than the 915 steel piece.

[island911]

Originally posted by Jim Sims
If the design of a part is governed by stiffness (flexing and deflecting under load) then switching from steel to aluminum may not be warranted as although aluminum is about 1/3 the weight of steel it is also only 1/3 as stiff. . . .

True, but many times the less dense aluminum will leverage thicker geometry for a much better weight specific stiffness. (ie an aluminum panel may only need to be 40% thicker to achieve the same stiffness as a steel panel. . .making the alum version weigh half as much)

(Not to imply Jim Sims isn't completely aware of this . . .just pointing it out for others benifit.)

I've also seen the "steel trans-mount meets hole-saw" story. . .a nice ending

[KTL]

Originally posted by island911
I've also seen the "steel trans-mount meets hole-saw" story. . .a nice ending

Not to be confused with the "steel motor-mount crossbar meets hole-saw story" right? Which incidentally also has a happy ending, resulting in a "oooooh! You must race your car?" comment from the onlookers.............