Insane speed in german cars... [Freightliner]

[jason@scirocco.org (Jason)]

At 05:37 PM 11/5/2002, John Van Vuren wrote:
>Actually, a Freightliner will do 100mph with a 450hp engine...  just not a
>VW 450hp engine.  They are geared to take advantage of torque, which a 450hp
>Cummins, Cat, Detroit, etc will provide in large numbers

Those of you who know me know that I'm not a fan of HP numbers, since they 
are misleading.  There is exactly one time where HP becomes important, 
though, and that's in top speed.

Gearing multiplies torque, but nothing effects horsepower:
         (Gear something down 2:1 and you put out 2x the torque, but at 
exactly half the speed, which means HP is uneffected).

All that torque is great for acceleration and pulling, but because it 
happens at such low RPMs, gearing will be very high and the result will be 
a reduction in torque.

You can calculate, for example, using the Cd and stuff, the horsepower you 
need to go a certain speed.  That number is, however, independent of 
torque.  So, while you're completely right that the Freightliner making 
450hp at 3000rpm makes massive amounts of torque, it unfortunately isn't 
helping all that much in top speed.

Jason

PS:  I have no idea if 450hp is sufficient to get a Freightliner to 
100.  My guess is that it probably is close to being enough...