list:

point is well taken. accelerating from a stop is certainly mainly a torque
issue. and cruising on the flats the tow isn't much of a torque or
horsepower issue, as wind resistance is not a lot higher and the extra
rolling resistance is not a major factor (and no external force is
required to keep the mass moving at constant speed along a straight line).
but what about going up a hill, say 10 deg? well, 82 hp = 45,100 ftlb/s.
assuming a combined weight of 8,000 lb, dividing power by
8,000 lb x sin(10 deg) = 1389 lb, yields 32 ft/s = 22 mph. in other words,
to lift 8,000 lb up a 10 deg slope at 22 mph requires the full rated 82 hp
of a 1.9 l. since there are other losses, such as wind resistance and so
on, and since it isn't a good idea to run an engine at full horsepower for
long periods of time, it would seem prudent to avoid hiils.

dan

>On Jun 23, 2004, at 4:12 PM, Robert Fisher wrote:
>
>Semi tractor trailer trucks weigh up to 80,000 lbs and have about 300 hp..
> A ratio of 267:1!  It's all about torque, not horsepower, when towing
>something heavy.
>
>Ryan