> -----Original Message-----
> From: owner-dakota-truck@buffnet4.buffnet.net
> [mailto:owner-dakota-truck@buffnet4.buffnet.net]On Behalf Of Jon Steiger
> Sent: Thursday, July 15, 1999 1:46 AM
> To: Dakota Mailing List
> Subject: DML: Yet another Carlisle post :-)
...
> One thing that seems strange to me is the shape of the hp and torque
> curves; if you can call 'em curves... HP just goes up in a straight
> line and just starts to peak and go over the top of the hill where
> I had the guy shut it down (around 5300rpm). The torque just sort've
> goes straight across; goes up a little, drops down a little, and then
> just goes straight across the page. Not much of a curve to either of 'em.
> (Anyone know if that's good or bad?)
I thought your nice, flat torque curve looked great. It shows you're
developing more force to propel the truck forward at lower RPMs. With
little rice burner engines, you have to wind them up to about 8000 RPMs
before you go anywhere. Might work fine for a sustained race on a twisty
track where you can keep it above 6000 RPM for the whole race, but since you
start from a standstill on a dragstrip I think the flat torque curve is a
good thing.
A small high-RPM engine might have the same HP peak, but it would have a
sharper slope and would have less power at lower RPMs. Since you do have to
spend time at RPMs less than redline, the power there does matter.
If I remember my physics, the work done toward acceleration (increasing
kinetic energy) would be the integral under the power curve, across the RPM
range that you're using. No, wait, I think it would be power over time. So
more power at low RPM will help push the truck faster and climb up to the
higher RPM even faster. I think...
The August Car & Driver has a little blurb about horsepower:
"In simple terms, horsepower is a multiple of torque and engine rpm. In
other words, horsepower is the *rate* at which torque is applied to the
crankshaft. Want to increase horsepower? You can do it by increasing
torque or by increasing engine rpm."
Sort of makes sense of the constant slope on your HP curve.
(It's too early for this... :-)
---------------------------------------------------------
Jason Bleazard http://www.bleazard.net Toronto, Ontario
current: '95 Dakota Sport white 4x4 Reg. Cab V6/3.9L/5spd
current: '98 Dakota Sport black 4x4 Club Cab V8/5.2L/Auto
RIP: '95 Dakota Sport black 4x2 Club Cab V6/3.9L/Auto
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