[DeTomaso] Engine Bay Brace question

[jderyke at aol.com]

.....'separation' of the braces? 

OK. Remember, all this is 'theoretical' since no one ever actually did 
full-scale stiffness tests. Both Goran, Dick Koch   and I all agree that the 
connector-tubes between the upper and lower tubes should ideally contact the 
upper tube AT THE FENDER ENDS of the upper horizontal tube, so as to not input 
bending in this tube which does take substantial side-loads. Since I doubt 
if there's any real force on the lower horizontal tube, the cross-braces can 
be tied in pretty much anywhere with about the same results.
BTW, nice craftsmanship on your inner fender plate welding, Gary. Someone 
spent some quality time doing this! 
On the factory GR-4s, the cabin-cage tie bars passed thru holes cut right 
through the rear window to attach to the upper inner fender panels very near 
the shock towers, which were then taking loads from many directions!   All 
the ones I've seen used bolt-in tie-bars going through holes cut in a Lexan 
window. Dunno what the LeMans cars used for a rear window; plexiglas was not 
homologated, so maybe that area was free.....
FWIW, the best 'theoretical' bay-brace design I ever saw was many years ago 
by Ron Siple in NV for a customer. It was about a 4" wide box-section 
fiberglas or carbon-fiber fabrication that covered the entire area between the 
upper brace-mounts on the inner fenders and ran all the way down to tie-points 
on the tops of the subframe rails- not to the backside of the a-arms. It 
had arch-buttressesvuilt in above the bellhousing/ZF for minimum clearance. I 
can't remember how the adjustment clevis was attached or if it even had one. 
I never got any in-use results so it may have been yet another idea 'not 
quite ready for prime-time'..... or maybe on a street Pantera that really 
didn't need it. 
FWIW- J Deryke