Torsional rigidty

[Digsy]

Has anyone got any proper torsional rigidity data for the stock Supra chassis (Nm twist input per degree front-to-rear flex).

Failing that, anything that might be close? I've had 8000Nm per degree suggested but no evedence behind it yet. Apparently the Elise chassis is 11800Nm per degree :eek:

Cheers,

[Chris Wilson]

Have searched but never found anything.

[Terry S]

Sounds like a Lotus engineer safe guarding his job to me ;) LOL

[Ian C]

That Elise needs a strut brace. It might increase torsional rigidity to 20,000Nm per degree ;)

-Ian

[JohnA]

I guess that the Elise has a much shorter wheelbase though, and the wheel axles are most probably narrower too, so it's much easier to make it torsionally rigid.

[Digsy]

You guys... :)

Just found some stuff on the interweb (http://www.maximum-cars.com/Cars/Car.php?carnumber=568&randomcar=1)that suggests the facelift might be stiffer than the the pre-1997 model.

...and apparently there's a Saab saloon out there up at 22000Nm/deg which kind of casts doubt on the 8000Nm/deg I had suggested for the Supra.

[Chris Wilson]

Well as the Elise has a bonded aluminium honeycomb chassis like an early F1 car ot's hardly surprising it has a higely stiffer structure than a massive steel shelled coupe! If you want to upset yourself jack up most modern cars under (say) one front wishbone and see how the door shut alters. Porsche 928's were touted as inredibly stiff by Porsche themselves. my wife and I have had several, on NONE would the door open and shut cleany when jacked up under one corner. Aerotops in most cars are far worse offenders than full steel roofed versions. Once you start looking at figures for carbon tubs and *PROPERLY* designed steel space frames you see just how desperately a road car needs a cage before any of the really stiff "suspension kits" cab have a prayer of working properly. This is one reason why I have always designed any kits for road cars to use softish spring rates. A spring can and should be damped, a jelly like bodyshell can't be... ;)

[JohnA]

The first time I jacked up the driver's side on the Supra, I was impressed by how much the rear wheel also rose up. That shows significant stiffness and rigidity.

In comparison the Calibra turbo would have the front wheel 2 inches off the ground (plus the few inches of suspension unload) and the rear wheel would still be firmly planted on the ground.
Totally different class, no comparison really...

[lovatt]

when i worked at ford we had a memo come round to all staff telling us not to jack one wheel up at a time on the new fiesta as it cracked the front screen ! i saw this happen with my own eyes at least 3 times