Torque or HP?

[victorfb]

again "LOAD" added to the equation. another good analogy.

[miketsouth]

Jer.....
Now you gonna mess it all up.
I was wrong, again. Just like before when Jim Lee sold more hats. Remember that Mr. McClure?
So, Jer, where is that Q window in the JPC
http://mywebpages.comcast.net/mikejet/forgettorque.JPG

[UBFJ #454]

By Definition:
Torque - The tendency of a force to produce rotation about an axis.
Work - The transfer of energy to a body by the application of force.
Power - Strength or force capable of being exerted.
Horsepower - A U.S. Customary System unit of power, equal to 745.7 watts.
Tq vs. RPM Curve as used in the context of this thread is a measurement of the rotational force that a given motor produces (or is capable of producing by its design/build) at given RPMs.
Hp vs. RPM Curve is the curve showing the rate (over a range of RPMs) that the motor is capable of applying that Force.
So What's The 'Argument' About?
Thrust in a jet boat is the forward-directed force (linear work) developed by the motor & pump system as a reaction to the rearward ejection of the water.
As jer points out ... With Jet Boats it's all about the amount of Thrust that can be delivered to, and out the nozzle ... Having an optimum setup (especially for a race boat) involves a whole lot more than just having the 'Right' Motor & Pump Impeller.

[steelcomp]

Victor, I'm going to be devil's advocate here and take you to task on this one. If i remove the 270 hp 454 from my duelly, and install nissans 320 hp V6, will i be able to pull the 5th wheel with 14000 pounds easier? if HP is a true measure of power, than it should pull much harder with the added 50 HP. HP is HP isnt it?
I say yes, but only if you can keep it in the range where it was making that hp. like with a 9 speed trans and 4:56 gears. Would that be suitable for towing? Not likely, because of the rpm you'd have to keep it at. Your big block makes it's power, or developes it's q at a lower rpm, therefore more suitable for towing.
Let's pick an equal q for both motors and see what we get.
390# @ 3600 = 267 hp. Sounds like a big block.
390# @ 4300 = 319 hp. Could be the Nissan.
I'm using what I think might be peak q rpms for each motor. It's a guess on my part and could be completely wrong. By going backwards through the math, you can see that the Nissan, being an OHCam, smaller CI, higher revving motor, vs the big block, big CI, lower revving motor, given the HP figures you gave, make the same Q. You'd have to keep the Nissan at 4300rpm to get the same power the big block makes at 3600.
I have NO idea how this relates to this thread, and after figuring all this my head hurts, but I thought it would be fun to try and compare. :coffeycup
edited to correct hp if anyone's checking

[miketsouth]

...
390# @ 3600 = 274 hp. Sounds like a big block.
390# @ 4300 = 319 hp. Could be the Nissan. ....
You'd have to keep the Nissan at 4300rpm to get the same power the big block makes at 3600.
I have NO idea how this relates to this thread
It gets to the heart of it. Let's extrapolate:
390# @ 1rpm = 13.4 hp. Could be Jer tightning a headbolt, well maybe not
390# @ 3600 = 274 hp. Sounds like a big block.
390# @ 4300 = 319 hp. Could be the Nissan.
You'd have to keep Jer tightning the headbolt and/or the Nissan at 4300rpm to get the same power the big block makes at 3600.
http://mywebpages.comcast.net/mikejet/forgettorque.JPG

[Infomaniac]

Hey how about that rain out in Atlanta? :notam:

[steelcomp]

It gets to the heart of it. Let's extrapolate:
390# @ 1rpm = 13.4 hp. Could be Jer tightning a headbolt, well maybe not
390# @ 3600 = 274 hp. Sounds like a big block.
390# @ 4300 = 319 hp. Could be the Nissan.
You'd have to keep Jer tightning the headbolt and/or the Nissan at 4300rpm to get the same power the big block makes at 3600.
http://mywebpages.comcast.net/mikejet/forgettorque.JPG
I think Jer's head bolts are a little overtq'd already!....JK jer.

[miketsouth]

My point is that torque on the shaft is completely independant of the power the shaft is producing.
It is somewhat less than coincidental that i mentioned Jer's headbolts
What's the key element for jet boats, torque or horsepower?
i say horsepower and
http://mywebpages.comcast.net/mikejet/forgettorque.JPG

[steelcomp]

Hey how about that rain out in Atlanta? :notam:Where TF is Atlanta????
Another planet heard from. How's life in the fast lane??!!

[LVjetboy]

Here's some rather long posts. If you're interested in the torque vs power debate please read and spend time thinking about what I've said. If after you read my comments you don't agree or don't understand, feel free to question with a quote from my post or challenge anything I've posted. We'll talk. I have no problem supporting my position. And I'd be happy to explain in more detail and post numbers to illustrate.
If instead you'd rather skip my long winded posts, could care less, or just favor accepted wisdom from the local engine guru, jet pro or whomever you consider a more knowledgeable source than me? Then I suppose you can just skip it move along and never know the difference.
Most of this has to do with the theory of how things really work. But when it comes to application, well, understanding the difference between torque and power won't ruin your fun in the sun or jet boat party time on the lake. In fact, you probably won't notice unless you're after that last mph or fraction of a second ET.
On to the debate...
jer