Understanding Dyno Readings -- is HP "real world" HP?

[russ_watters]

The ? is can you gear around a major lack of torque and one group says no and the other yes. This is crucial in being able to understand what a dyno is really telling for motor application.

I would hope by now you know what the correct answer is (whether you accept it or not), and why. Can you repeat it back to me so I know you are paying attention to what you have been told? I don't want to go around in circles.

The rest of your post is more gibberish and handwaving of the same type as before. It provides you no value and I once again urge you to be more rigorous in your analysis. You are never going to have a reason to believe what the science/math tell you if you just keep throwing out meaningless numbers and gibberish phrases!

 

[RogueOne]

Yes, you can gear around low torque coming off the crankshaft, as long as it has enough horsepower to do that amount of work. All you are doing is increasing the leverage that the engine has over the load that it is trying to move.

 

[jack action]

The ? is can you gear around a major lack of torque and one group says no and the other yes.

The answer is «yes».

The ? is can you drive that 1200 hundred tons to that point of 40 MPH with any 2300 HP engine and gearing.

Yes.

Even the top engine builders said Nasa science and a billion $ transmission you may be able to figure out how top do it but not at all in a practical sense.

It wouldn't cost a billion $ to build such a transmission as there is no magic about the concept. But it is true that such a drivetrain would probably not be practical (too many gears to shift, loosing power between gears).

It's not that it lacks the power it lacks the drive coming from the crank to build RPM under such tonnage, this is what the engine builders were saying and they were saying a lot of people do not understand this so a higher torque engine is more powerful in real world use even though on paper they may look the same and you just gear for what you want.

Yes it is because it lacks power. Because the engine drops to a rpm that delivers a lot less power.

I am saying even if average HP at RPM are similarly matched and the higher rpm turning engine is not peakier.

You are maybe saying this, but you are constantly referring to examples which do not have the same average HP at RPM (Pro stock & large diesel truck engines). If they were, you wouldn't see a difference in the power delivery. Even the number of gear ratios would be the same. The only difference would be the final drive ratio.

 

[Moretorque]

Thanks for all the replies, I edited my previous post above # 35 to make it real short and sweet to my real ? and belief so for those interested please refer to it.

I am admitting I am probably wrong about this but I am real curious.

Thanks Jack for pointing out my error in above post .

Any input is welcome and thanks...

 

[RogueOne]

Here is the answer to your question:

When you move the system, you are doing work to it. If you do work to the system, you move it.
If you have an engine that is capable of making 5 horsepower, then it can do 5 horsepower worth of work to the system. If you have an enormous load, then you can move it with that 5hp engine by gearing the engine (giving it a lot of leverage) over the system. The gearing increases the amount of twisting force that is applied to the load. However, it decreases the RPM at which the twisting force is applied. So the engine is making the same horsepower and torque at the same speed as before, but that is being used to drive a gear that has a lot more twisting force over the load that you're trying to move.

You increase the twisting force being applied to the load. You decrease the speed at which the twisting force is applied. The horsepower output is unchanged by the gear ratio, aside from parasitic friction (minimal losses). The gears connect the engine to the load or object that you're trying to do work to. The engine operates at its normal speed and makes its normal amount of torque as well as its normal amount of horsepower.

Look at gears like they are levers. They give leverage. If you have a large enough lever, you can move any load by putting any amount of force on the side farthest from the fulcrum.

 

[Moretorque]

Thanks for the above post, it's my fault because I did not understand how to explain what I was looking for.

Here is an example that sums up my belief which could be wrong and according to most it is but some have said it is correct but I believe I may have misinterpreted what they told me from not giving them all the correct parameters. It is basically all things being equal does a engine that makes the power earlier have more power.

The Mack Maxidyne 238 RWHP was known to be able to push 35 tons to 62 MPH with just a 5 speed. It has a torque rise of 52% and was considered a little GEM. Underpowered by today's standards but the speed limit was lower decades ago.

You have the Mack Maxidyne that makes 238 HP at 1500 RPM and you have another engine that makes 238 HP ay 4500 RPM. We will say they both have torque rises of 52% so the power bands are identical on paper and you just cut the gear ratio by 3 for the second engine and they should be the same in real world use.

Now the Mack does have the advantage of more torque coming off the crank to get the load up and going and as stated it was mated with just a 5 speed to move 35 tons to 62 MPH. It is my belief the second engine in this comparison could not do the job near as well with a 5 speed and would need more gears to drive the load as well even though they were all laid out the same ?

This is what I am after.

It means HP is HP if I am wrong or the dyno lies and you better be able to make adjustments because something is lost in math translation...

 

[russ_watters]

Ok, that's enough. You can either accept the answer or not, but the thread is going around in circles and not getting anywhere and I won't let it keep wasting our time. Closed.