I see we come to the same conclusion but a few things I disagree on:
Considering a strain gage will only indicate a particular setup's stresses (will require testing of all, or will still require further reverse engineering to simulate the proposed mount setups in order to find which is superior), and that the stresses on the mounts are a few quick measurements and some quick hand calculations away, I don't see why not using strain gages even an issue, muchless a big one. Please feel free to educate me.
the numbers from a strain gauge would allow you to size your stock for a safe design factor and little more.
i want to see the incurred stresses simply to find order of magnitude -
80% of my learning on these things is straight out of college texts,
and we dealt more with bridges and proverbial greased pigs than an
unsprung clutch dumped at 5k
I think it would also be particularly interesting to compare left and right hand loads and perhaps build each differently as the case allowed - as making the mounts in multiple parts could significantly reduce costs in materials.
considering my position, i think it would be pretentious of me to claim to "educate" anyone
![Wink [;)]](/emoticons/emotion-5.gif)
. i consider this to be an excercise in speculation and problem solving, and i'm no expert
Funnily, I actually did some calculations for FSAE and on our ProMod (for a class) about the 'pendulum motion' about the trans mount (I referred to it as "residual engine torque about the z axis") and I can safely say the effects are negligible. And I even used exaggerated figures (from reality) in those calcs. I'll dig up the papers, scan them and post them in the files section on this site. Remind me about those in the new year.
I would be very interested in this, as my old S14 seemed to have considerable "residual engine torque about the Z axis" - but it could have also been skewed perception of rotation about the crank due to the engine bay
The lack of fatigue strength may become a long term issue on Fred's setup (if he doesn't retain his current mounts), but I seriously doubt it would cause failure of the webs. I see the block failing in the area of the mount or even bolt hole elongation long before the webs even starts to show signs of deflection.
I hadn't really thought of the block taking stresses for which it was not designed, but in your proposed sandwich design, i think it would work out well. the only reason i brought fatigue into this at all is that thus far, i have enjoyed watching fred's build and would like to see it continue
for my swap, i have to be fairly agressive - i will be removing the front chassis rails, replace them with rectangular tube with flanges to facilitate a removable front end a la Z33 or Bimmer and adding only the bracketry necessary to support the suspension.
I'm still in the "refabricating the strut towers" stage, but i intend to use fairly traditional engine mounts, as exhaust routing is an issue, and i have not found a better idea
if you have any hich clearance mount ideas, i am all ears