[QUOTE]Originally posted by micah
[B]
If you were thinking this, I think I see the source of the confusion. HP is power; or WORK over time, or torque TIMES revs; but not torque over time, at all.

Again, there is no way that a dyno can measure your engine's torque unless you know the intermediate gear ratios. But the dyno can tell how much POWER your engine is putting out, minus friction. The fact that a dyno may measure torque internally is simply a confounding factor in this conversation, which is about flywheel power vs torque.

Anyone who's familiar with dynos can tell you that a dyno can tell you power without knowing anything else, but to get torque from it, you need to give it all kinds of information about tire diameter, gearing, and engine revs. This tells you that power is what's being measured and torque is what's being calculated. That's why the definition of a dynamometer is a device that measures power.

 

This is a VERY CLASSIC fallacy. First thing I learned in engineering school was not to mix up torque and work just because they're the same units. The radians term is very easy to forget, and it's easy to think that you can leave it out because it's unitless.

For real!? Check the web, there's a ton of ways you can make a dyno work without a torque measurement. Or just think about the pedals hooked up to the generator and light bulb - there's no torque being measured there, even though, yes, torques exist in the system.
I really think you're confusing yourself by thinking about the torque in the drum. That's part of how the dyno works internally, and it has nothing to do with the torque of your machine (usually a car - but the plank example was to try to show you that you can have a torque in the dyno when the device you're measuring doesn't have any torque associated with it!)

In general I recommend checking a textbook or one of the several primers on the web about work, power, force, torque, and distance.

[forrest]And that's all I have to say about that.[/forrest]

 

 

Come on guys.
Lots of people here obviously studied physics to some degree, did you all skip your calculus classes?

We are not talking about constant rotational velocity gas turbines here.

Peak numbers don't mean anything if you don't factor in the shape of the curve as it varies with time (RPM), torque OR power.

It doesn't matter if you know the shape of the torque curve with time (RPM) or the shape of the power curve with time (RPM) they can then both give you the WORK DONE.

Now factor in the number of gears and their ratio's you can now optimize the shift points to perform maximum work in each gear in the shortest time.

A great car would run a gas turbine through a CVT. This would provide theoretically infinite shift points along a constant power curve maximizing the Work!

NS2000X

 

All you guys that lament the lack of "low end torque" should wait a few years for the reintroduction to the market of electric automobiles. With them you get the maximum amount of their torque at 0 RPMs.

 

[QUOTE]Originally posted by micah
[B]
This is a VERY CLASSIC fallacy. First thing I learned in engineering school was not to mix up torque and work just because they're the same units. The radians term is very easy to forget, and it's easy to think that you can leave it out because it's unitless.


For real!? Check the web, there's a ton of ways you can make a dyno work without a torque measurement. Or just think about the pedals hooked up to the generator and light bulb - there's no torque being measured there, even though, yes, torques exist in the system.

I really think you're confusing yourself by thinking about the torque in the drum. That's part of how the dyno works internally, and it has nothing to do with the torque of your machine

 

Torque is not work. Think about it.
If it doesn't move there is NO WORK!!!

Here try this:

Walk out to the end of a 10ft 'I' beam, that is solidly attached at the root. Your on a cantilever right? Well how much work do you think the torque you are applying at the root is doing?



Careful with your statements.

NS2000X

 

 

[QUOTE]Originally posted by NS2000X
[B]Torque is not work. Think about it.
If it doesn't move there is NO WORK!!!

Here try this:

 

The chicken or the egg? Which came first?

If a tree falls in the forrest and no one is there to hear it does a it make a noise?

Choclate or vanilla?