Richard Konnen wrote:
 >
 >  Paul,
 >   So if I understand the variable intake chart, you want the RPM to be at
 > max torque point and with the variable intake you can adjust for the
 > efficiency? If your shooting for max torque at 6K then why is max HP so
 > important? Such that it shows your making 600+ HP at 9Kbut the torque

goes

 > away after 6K, so is the extra HP useful after that point. This is also
why
 > I never understood why drag racers would wind these engines up to 10 or
11K
 > if their torque peak was at 6 or 7K.
 > Tanks,
 > Richard Konnen

The difficulty in understanding torque (a twisting force along an axis) is
that no component of time and distance is present. So, if you put your torque
wrench on a head bolt and tighten it up, you are performing work, and generating
horse power because the wrench is moving. The equivalent of lifting a weight
in a specific period of time. (33,000 pounds lifted against the force of
gravity, one foot in the period of one minute equals one horse power). The work
required to move the wrench against the bolt while it is turning (some part of a
revolution per minute) is horse power. When the bolt tightens and the wrench
clicks, or the indicator shows the correct torque has been established, no
additional motion (time and distance) is accomplished so there is no more work
being done.

Pulling on the wrench is effort and is recorded in foot pounds of torque
applied to the head of the bolt (axis). So a torque wrench only one foot long held
in the horizontal with a one pound weight hanging one the end will be
producing one foot pound of torque against the bolt head. Properly done, this wrench
could hang on this bolt head with the weight attached and produce one foot
pound of torque for all of eternity.  Since there is no motion involved, (time
and distance) there is no horse power to measure.

Horse power is the measurement of work that adds time and distance to torque.
So the 5252 used in the calculation is a constant to account for time and
distance. Let us say that an example engine can deliver 100 foot pounds of torque
at 5000 RPM. That means if we rig up a brake caliper to grip the flywheel one
foot out from the center of the crank, and the caliper is sitting on a scale,
we could actuate the caliper to create drag on the flywheel until the scale
reads 100 pounds before the engine RPM would begin to drop from 5000 RPM. That
would be 100 pounds of force, one foot out from the crank centerline (torque)
times 5000 RPM (time and distance) over 5252 = 95.20 horse power.

Or if the time distance thing is not clear, the RPM is (revolutions) just a
simple count, times the time required, (one minute). The distance is the one
foot from the centerline of the crank times
3.1416 per revolution.

Or, for every revolution, that 100 pounds is being raised against the force
of gravity 3.1416 feet.

Since the amount of work that can be completed has time and distance as part
of the formula, revving the engine higher (more distance per minute) means
more work will be performed, (higher horse power).

The term "Brake Horse Power" actually refers to the "Brake" or strap on a
pulley used to measure torque on old dynamometers. Now the "Brake" is a water
coupled absorption unit.

Lynn E. Hanover

 
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