Big Three road tests

I wonder what kinda thrust that hooker takes?

Sport45 wrote:


buddyIam wrote:

Sports 45,

You made my point. You said it very well.

We should be concerned with power. Not horse power.

Horse power is an approximation.

It is based on torque and speed/distance. That is power that can be scientifically measured.

You don't need hp or power to have torque. But you must have torque to have power or hp.

Hp=rpm×torque/5252. The formula says it all. If there is zero rpm. Torque can be 1 million and hp would still be zero.

If hp is any number greater than zero. Then neither torque nor rpm can be zero.


Torque and rpm are the determining factors. Not hp. Hp is not a measurement it is an approximation dreamed up to sell stream engines.


Now I understand. You want to live in your own little world where you compare power by looking at a torque curve and multiplying torque and rpm. That works. The rest of us just use the HP curve where the calculations have already been made.

But I bet if you compare the power levels of two engines in your world you'll find the one that has 20% more power also has 20% more power in our world. Doesn't matter if you use horsepower (which you seem to dislike), elephant power, or kilowatts.

Big diddily do... my truck produces 1982lbs of thrust!!! Beat that!! (horse power advocates.... that's POUNDS OF THRUST)
:B

Sport45 wrote:

buddyIam wrote:
Sports 45,

You made my point. You said it very well.

We should be concerned with power. Not horse power.

Horse power is an approximation.

It is based on torque and speed/distance. That is power that can be scientifically measured.

You don't need hp or power to have torque. But you must have torque to have power or hp.

Hp=rpm×torque/5252. The formula says it all. If there is zero rpm. Torque can be 1 million and hp would still be zero.

If hp is any number greater than zero. Then neither torque nor rpm can be zero.


Torque and rpm are the determining factors. Not hp. Hp is not a measurement it is an approximation dreamed up to sell stream engines.

Now I understand. You want to live in your own little world where you compare power by looking at a torque curve and multiplying torque and rpm. That works. The rest of us just use the HP curve where the calculations have already been made. :)

But I bet if you compare the power levels of two engines in your world you'll find the one that has 20% more power also has 20% more power in our world. Doesn't matter if you use horsepower (which you seem to dislike), elephant power, or kilowatts.

When a big RV is going down the level highway at 70 mph it is mainly the wind resistance on the vehicle that is defining the amount of torque necessary on the rear axle to maintain the vehicle speed. Slow down a bit and the torque requirement drops significantly.

When that heavy truck and trailer hit the big twisty hills things are a little different. You will likely be traveling a little slower and wind resistance is not playing nearly as big of role. The incline angle of the hill largely determines the amount of torque on the rear axle to maintain speed. If the engine isn't able to produce the necessary torque the truck slows down. Even though slowing down reduces the power required to maintain speed it makes little difference to the torque requirement which is largely being determined by the incline not wind resistance. So if the engine's torque curve is flat or falling off as the rpms drop the truck will rapidly slow down till a downshifting occurs. With this truck it is the transmission that is responsible for the torque increase. An engine (such as the Cummins) which has a significant torque rise as the rpm drops will have a higher tendency to pull the hill and downshifting will not be as often required. All this can be seen with a quick glance at an engine's torque curve.

Who's sister is a hooker? Anyone have her phone number?

The 60' and 70's model fire trucks I drove for our East Texas volunteer fire dept in the mid-80's were the same way. They were all F-600 or F-700. Most had 370 gas engines and 4-spd tranny's with 2-spd axles. They'd get there, but not in a hurry.

Seemed silly to be running lights and siren with folk trying to pass us on the hills. :)

john&bet wrote:
Boy, I am glad you guys that are in such a big hurry don't drive behind the '13 28k+ school bus that I drive daily. With only 250hp and a 2500 rev limit and a 5 speed Allison it takes over 1500' to get it up to 55 mph on flat ground.

Or the 1992 IHC dump truck I have, with a 175/335 NA 7.3 diesel with a 7 speed spicer. Helps that I have 4.33 gears, 32" tires, and a 10.08-1 first gear to get going at 26k lbs too! Altho I can get 30k lbs to move up a 30% grade, sloooooooooooowly that is!

Marty

Boy, I am glad you guys that are in such a big hurry don't drive behind the '13 28k+ school bus that I drive daily. With only 250hp and a 2500 rev limit and a 5 speed Allison it takes over 1500' to get it up to 55 mph on flat ground.

Sports 45

I think we have solved the torque v hp wars. HP was great when we only had one steam engine. It didn't really mean any thing but it was good sales pitch for the steam engine salesmen.

But once there were two steam engine builders what was the point in comparing them to a horse. The comparison needed to be made to the other engine so why not just use power for the comparison.

Power relied on torque and rpm, not horses. ;)

buddyIam wrote:
Sports 45,

You made my point. You said it very well.

We should be concerned with power. Not horse power.

Horse power is an approximation.

It is based on torque and speed/distance. That is power that can be scientifically measured.

You don't need hp or power to have torque. But you must have torque to have power or hp.

Hp=rpm×torque/5252. The formula says it all. If there is zero rpm. Torque can be 1 million and hp would still be zero.

If hp is any number greater than zero. Then neither torque nor rpm can be zero.


Torque and rpm are the determining factors. Not hp. Hp is not a measurement it is an approximation dreamed up to sell stream engines.

Now I understand. You want to live in your own little world where you compare power by looking at a torque curve and multiplying torque and rpm. That works. The rest of us just use the HP curve where the calculations have already been made. :)

But I bet if you compare the power levels of two engines in your world you'll find the one that has 20% more power also has 20% more power in our world. Doesn't matter if you use horsepower (which you seem to dislike), elephant power, or kilowatts.