Quoting "John G. Napoli" <john@xxxxxxxxx>:
> Exactly. That's why lockup clutches on trannys with torque converters
> are
> very important. Depending on the stall speed of the converter and the
> weight of the car, you can see a 10% drop in engine rpm once the lockup
> clutch is engaged, at highway speeds. That's a measurable improvement
> in
> mpg. Fluid couplings would show a much smaller improvement. Hard to
John, its a lot less than that for cars like our 60's and early 70's
Imperials. For normal crusing it can get as low as 1% or even less (see my
prior post). Even at WOT, as long as the engine speed is around 4000 rpm or
more, it will be of the same order (1-2%). Modern cars with small engines have
high stall converters, and these will slip a lot more. Also, these engines
have a lot less torque, so the lock-up clutch can be a ot weaker, and it often
locks on all gears.
D^2
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