GMs in IT

[JeffYoung]

Correct.

Interesting, so you do not think the advantage of adjusting rear camber and toe rises above the noise level in car differences.

Dick/Earl, having driven Miatas, the 240z, the TR8 and Ron's Lola at speed at VIR, CMP, Roebling and others, I've yet to really see where the TR8 is at a serious disadvantage to the others.

Once we eliminated bind and settled the axle down with a good tri link and panhard setup, the back end does not mover around. I obviously don't get any camber back there, and that hurts some, but as someone pointed out I also don't get toe and camber change as the axle moves.

By subjective feel, the only place the TR8 seemed at a disadvantage to the Z and the Miatas before the tri-link was Hog's Pen. But now even there I pull most good RX7s and Z cars out of the hole -- watch the vid Ron posted (and that was BEFORE tri link).

Earl, yes, I can run the curbs at VIR fine. The car doesn't like the channelled FIA curbs at CMP, which I understand are coming to VIR for next year, yay, but not sure any of our cars really do.

I think with our 150-180 whp cars, the live rear just isn't that much of an issue.

Bill, no off the shelf fix for me either, but it was not hard to have one, a good one, fabricated given how open the rules are for a live rear axle with the 'traction arm" allowance.

[billf]

Want to know what happens to a live axle when jumping curbs??? Just watch ONE V8 SuperCar race from Australia, and you will see EVERY car jumping curbs. They are mandated a live axle, even though the chassis are originally built with IRS, and mandated to run a spool at all events.

When the cars jump the curbs, the wheels have liters of air under them. The effect is minimalized by the spool which delivers 100% power to the opposite (still in contact with the pavement) wheel.

Quite the lesson in drivetrain dynamics...

Jeff,

Sometimes the live axles "bend" in service and acquire some camber... I'm not sure the mechanisms are fully understood....

But the lack of camber and toe changes surely make the live axle a good choice if one can tolerate the expected unsprung weight.

Finally, I believe the lack of toe and camber change, in addition to the ability to harness the axle torque reaction, gives the live axle an advantage in traction out of the corners with especially high horsepower cars. The new generation Mustang is certainly competitive with the competition, all of which have IRS...and its corner exit is impressive. Only Porsche is better, and that probably is because of its greater rear weight percentage.

Bill