GMs in IT

[Ron Earp]

3.4 needs a torque adder? What else does? Where is the line drawn?

Apparently it is a "We know it when we see it" thing. Empirically it is a "Domestic Penalty" - TR8 (ITS, maybe it has one, domestic motor), Mustang V8 in ITR (does have one), Camaro V8 in ITR (has one), Corvette (not classed but would probably have a torque adder in ITR) - all domestic powered cars with torque adders.

RX7s have no torque to speak of, but at 8000 RPM that twisting force makes a lot of horsepower, and horsepower tells us how much work we can do with the motor. There are many torqueless motors that perform just fine - Miatas, GSR, etc. because they produce good horsepower in the framework of the class they race. Their horsepower peaks are broad enough to get the job done.

Naturally I'd take a broader horsepower curver over a narrower horsepower curve as the area under the horsepower curve that is accessible with the gearbox is all that makes any difference. But in looking at a lot of dyno plots I'm not entirely convinced that 2V large displacement domestic engines are producing horsepower curves that are appreciably wider than small displacement imports. Especially when most of the import motors have four valve heads which provide for impressive breathing capability.

But besides all of that, those two GM cars should be in IT. Shame about the Camaro as it doesn't have disc brakes in the rear. Typically GM does ok on brakes but they left drums on the car until it got the more powerful 3.8L V6.