Rotational torque
- Thread starter flattop1
- Start date
We all know it requires the same amount of energy expended to do the same job.
Doesn't matter if we lift the 50# straight up six feet or use a gradual slope or ramp, it requires the same amount of work.
Same as accelerating the same mass to the same axle speed.
What is important is if you have the ability to do more after you get there.
Doesn't matter if we lift the 50# straight up six feet or use a gradual slope or ramp, it requires the same amount of work.
Same as accelerating the same mass to the same axle speed.
What is important is if you have the ability to do more after you get there.
paulkish
old fart
I'll take a guess at the things you can do "to go faster" via only a change in physical properties, given the amount of input work available does not change:
1. reduce resistance
2. maintain momentum more efficiently
3. lighten the parts transferring the work
4. where the rubber meets the road reduce work used to accelerate in any direction except forward
5. stiffen sidewalls
6. raise air pressure
7. run closer to the limit of grip
8. ?
Always more questions. ...
If any of the above are ok, which might of inspired this thread or fit the jist of this thread?
My answer is I think it's only 1 and 2.
1. reduce resistance
2. maintain momentum more efficiently
3. lighten the parts transferring the work
4. where the rubber meets the road reduce work used to accelerate in any direction except forward
5. stiffen sidewalls
6. raise air pressure
7. run closer to the limit of grip
8. ?
Always more questions. ...
If any of the above are ok, which might of inspired this thread or fit the jist of this thread?
My answer is I think it's only 1 and 2.
Last edited:
LMAO
Sure seems you would like to hijack?????
If you have done your homework with the correct data, you should already know the answer.
Or, is it that difficult to interpret the information you have?
If, when torque drops off after peak horsepower, rpm at the engine and the axle is the same, but one setup is transferring more torque, would not that setup have an advantage?
The momentum component allows you to take advantage of this situation.
Reminder, nothing changed between setups but the driver combination for the same speed ratio.
Sure seems you would like to hijack?????
If you have done your homework with the correct data, you should already know the answer.
Or, is it that difficult to interpret the information you have?
If, when torque drops off after peak horsepower, rpm at the engine and the axle is the same, but one setup is transferring more torque, would not that setup have an advantage?
The momentum component allows you to take advantage of this situation.
Reminder, nothing changed between setups but the driver combination for the same speed ratio.
Last edited:
alvin l nunley
Site Supporter
(physics) A measure of energy expended in moving an object; most commonly, force times distance. No work is done if the object does not move.
Definition of Work
Work = force times distance (look it up in Wikipedia Dictionary)
Imagine if your ramp is flat, now imagine if it's slanted, 10°, 20°, 30° etc. etc. all the way to straight up and down. Obviously it takes a force to push the Kart across the flat, and even more force if the ramp is anywhere from flat to 90°. The steeper the ramp, the more force required. The more work expended.
Doesn't matter.
The net result is you lifted 50# up 6 feet.
Yes, more effort is required to move up a slope than across a flat surface.
But you are talking about 2 entirely different things
Raising an object require the same amount of work, whether lifting straight up, or sliding up a slope. The differences being we use less force over a greater distance when using a slope.
Might need to look at inclined planes, etc.
Use of leverage is also the same
Last edited:
Ted Hamilton
Helmet Painter / Racer
When it comes to racing engines, all I care about is RATE OF WORK. I want whatever gets me down the straights fastest. I also want quick rate of acceleration for the starts, and for anything that kills my momentum. So, to determine my gearing, I'm going to find the region in the HP curve that has the most area UNDER THE CURVE, that represents THE HIGHEST RATE OF WORK GETTING DONE. This will allow for the best acceleration. Period. This region will be where the volumetric efficiency of the engine and the geometry of the engine are best balanced, and the most torque is available. Torque is how hard it's pushing, HP is how quickly it's using that push. That's my understanding...rarely complete, always adding and refining.
alvin l nunley
Site Supporter
If only it was that easy!! Still, I agree for the most part, power under the curve.
paulkish
old fart
Then i'm thinking you primarily either have a lot of little miniature pony's pulling you or one huge draft horse.
Is it when torque is above hp you'll get better performance from the huge draft horse and when hp raises above torque and the herd of little pony's take over?
I'm guessing if there's need for more power/work to get the job done, if your under powered at the limit of torque then keep the draft horse up front as long as you can?
But if there's no need for power because what you have is able to exceed grip then get the most pony's up and at it as soon as possible.
Then there's the driver and the drivers ability to even be able to recognize it when additional pony's come on line.
Someone on another thread mentioned Don Ott and his kids in cars with his engine.
I once asked him a question about being able to bring on more pony's at high rpm. The exact question and talk was about using additional high speed pop off's to delay the torque curve going down.
Answer learned from the discussion was with the amount of power top engines now are making per what's needed, 99% of the drivers will not be able to see any difference. I said thank you.
But this is not about racing stuff with more power then you'll ever need it's about momentum racing and help reducing momentum eating mechanical differences.
I don't know the subject and i'm throwing my thoughts into in hopes what's wrong will be noted and i'll learn.
Right not I can go back, read this thread again from the start and during early reading think I see the points.
But when I get on down the road reading on farther I get lost not remembering any of the why about my thinking I see it.
Sure wish I could inhale the first presented idea/understanding and be able to use it on down the road.
But it gets lost in the shuffle. ...
Is it when torque is above hp you'll get better performance from the huge draft horse and when hp raises above torque and the herd of little pony's take over?
I'm guessing if there's need for more power/work to get the job done, if your under powered at the limit of torque then keep the draft horse up front as long as you can?
But if there's no need for power because what you have is able to exceed grip then get the most pony's up and at it as soon as possible.
Then there's the driver and the drivers ability to even be able to recognize it when additional pony's come on line.
Someone on another thread mentioned Don Ott and his kids in cars with his engine.
I once asked him a question about being able to bring on more pony's at high rpm. The exact question and talk was about using additional high speed pop off's to delay the torque curve going down.
Answer learned from the discussion was with the amount of power top engines now are making per what's needed, 99% of the drivers will not be able to see any difference. I said thank you.
But this is not about racing stuff with more power then you'll ever need it's about momentum racing and help reducing momentum eating mechanical differences.
I don't know the subject and i'm throwing my thoughts into in hopes what's wrong will be noted and i'll learn.
Right not I can go back, read this thread again from the start and during early reading think I see the points.
But when I get on down the road reading on farther I get lost not remembering any of the why about my thinking I see it.
Sure wish I could inhale the first presented idea/understanding and be able to use it on down the road.
But it gets lost in the shuffle. ...
Last edited:
You will need to take notes to stay on track.I don't know the subject and i'm throwing my thoughts into in hopes what's wrong will be noted and i'll learn.
Right not I can go back, read this thread again from the start and during early reading think I see the points.
But when I get on down the road reading on farther I get lost not remembering any of the why about my thinking I see it.
Sure wish I could inhale the first presented idea/understanding and be able to use it on down the road.
But it gets lost in the shuffle. ...
Also, ignore all the posts that lead off track to some rabbit hole somewhere.
It is hard to maintain train of thought also with distractions while trying to relate the information.
There is always at least one kid in class who has no interest, but insists on being the center of attention.
Last edited:
paulkish
old fart
trying to simply put it ...........
torque and hp curves will cross
i'm thinking moving where they cross (left and right on the charting I normally think of) will shift how you are able to use either additional torque or hp depending for racing needs.
Some racing depending on available grip and hp will need the crossing moved left and other racing will need it moved to the right.
LOL. .... the above statement I made instantly made me think about thinking if there is also a need to have the crossing point as high as possible.
... instant reply to myself said sure ya gota move it up too.
then the thunkin part of me started questioning moving it up thunkin it AGAIN depends on need.
dang this thunkin is hard on old ancient already snapped together brain cells. ...
thanks for the reply.
torque and hp curves will cross
i'm thinking moving where they cross (left and right on the charting I normally think of) will shift how you are able to use either additional torque or hp depending for racing needs.
Some racing depending on available grip and hp will need the crossing moved left and other racing will need it moved to the right.
LOL. .... the above statement I made instantly made me think about thinking if there is also a need to have the crossing point as high as possible.
... instant reply to myself said sure ya gota move it up too.
then the thunkin part of me started questioning moving it up thunkin it AGAIN depends on need.
dang this thunkin is hard on old ancient already snapped together brain cells. ...
thanks for the reply.
We need to be thinking a lot further up the horsepower curve, depending on the engine. Stock predator will not reach this rpm by rule.trying to simply put it ...........
torque and hp curves will cross
i'm thinking moving where they cross (left and right on the charting I normally think of) will shift how you are able to use either additional torque or hp depending for racing needs.
Some racing depending on available grip and hp will need the crossing moved left and other racing will need it moved to the right.
LOL. .... the above statement I made instantly made me think about thinking if there is also a need to have the crossing point as high as possible.
... instant reply to myself said sure ya gota move it up too.
then the thunkin part of me started questioning moving it up thunkin it AGAIN depends on need.
dang this thunkin is hard on old ancient already snapped together brain cells. ...
thanks for the reply.
The number of rpm where hp and torque are the same will always be 5252 rpm.
The number we are looking at is torque at peak horsepower rpm and beyond .
Maybe the best way is to look at target rpm torque.
Then look at torque thru rpm drop in the corners.
This is the only rpm we are using while racing.
I can try to explain it to you.
I cannot understand it for you.
Last edited:
paulkish
old fart
I've read endless words on here asking and explaining about what rpm to shoot for with various classes.
From it I would also expect builders build to complete engine output at a specific rpm.
Though it is obvious now you have stated it I cannot recall ever reading one word on here relating engine performance to the amount of corner/turn rpm drop. thank you
Writing this also instantly presented me this question.
Either end of the track can be split into one or more turns.
Might you build to one specific turn when multiple turns are involved at an end of the track or build to the greatest rpm drop at an end of the track?
From my (proly wrong) understanding of what you already offered in this thread, I'm thinking and engines length in time of useful power production beyond the crossing of torque and hp might be key????? <again proly showing i'm not yet understanding. ...
And one more question. Does how an increase in hp along with expected decrease in torque relate to each other providing maybe a third line to be charted determine how much is available from an engine after hp and torque cross? yep.. again proly showing how I don't yet understand it. ...
From it I would also expect builders build to complete engine output at a specific rpm.
Though it is obvious now you have stated it I cannot recall ever reading one word on here relating engine performance to the amount of corner/turn rpm drop. thank you
Writing this also instantly presented me this question.
Either end of the track can be split into one or more turns.
Might you build to one specific turn when multiple turns are involved at an end of the track or build to the greatest rpm drop at an end of the track?
From my (proly wrong) understanding of what you already offered in this thread, I'm thinking and engines length in time of useful power production beyond the crossing of torque and hp might be key????? <again proly showing i'm not yet understanding. ...
And one more question. Does how an increase in hp along with expected decrease in torque relate to each other providing maybe a third line to be charted determine how much is available from an engine after hp and torque cross? yep.. again proly showing how I don't yet understand it. ...
alvin l nunley
Site Supporter
All that information may be good, it's hard to know, but that horsepower chart is way off. Notice where the 2 lines cross, you'll never see that on a real dyno chart. If this chart is that wrong, how right can the article be?
When you graph (in that RPM range) "any" engine on a dyno, the torque and the HP will always cross at 5252.1.
Torque 10 x RPM 5252.1 divided by 5252.1 = 10 HP. It just can't be anything else!!
Ted Hamilton
Helmet Painter / Racer
A question..... If I'm doing LTO, and my typical RPM drop is only 400 rpm, why wouldn't I gear the engine so that it had the most power in that range? Are we really saying that in typical LTO kart racing, we're running at the upper RPM limit, so far beyond the engine's "normal" powerband, that we see some sort of difference in the curve that is forcing us to compensate elsewhere?
It's kinda' like a v12 spinning at 8000 rpm vs a turbo 4 at 17000.... they're both doing the same amount of work, and both have equal HP ratings, but if you need shear grunt, you'd better go with the v12 because its' torque potential is much higher. Since its got a smaller powerband, it will be more sensitive to disturbances in speed, however... yes, no?
It's kinda' like a v12 spinning at 8000 rpm vs a turbo 4 at 17000.... they're both doing the same amount of work, and both have equal HP ratings, but if you need shear grunt, you'd better go with the v12 because its' torque potential is much higher. Since its got a smaller powerband, it will be more sensitive to disturbances in speed, however... yes, no?
alvin l nunley
Site Supporter
Lots of assumptions! Too many to make any kind of a reasonable guess. Show me the power curves, calculate the horse power under the Usable curve, show me the track. What are the gear ratios? Shall we assume a transmission in use? Show me the shift points and the number of them. There's a reason why formula 1 cars use 9 shift points!
Sometimes the simplest of questions end up not being so simple!
Sometimes the simplest of questions end up not being so simple!
Need to look at graph again.
Torque and hp cross at 5252
air fuel ratio and torque lines cross at 43-4400 probably an unnecessary item on the graph.
Peak Hp shown as 9.83@4700 This is where engine will do the most work.
peak torque shown as 14.10@2300 Is going to be difficult to keep idling much below this level.
alvin l nunley
Site Supporter
You're right, my bad. I mis-read the scale.
I've never seen a chart where the horsepower and the torque dropped in near unison that much. I'm going to blame it on my faulty vision. lol
I did notice there's an increase in fuel flow at the same time that both the other curves are falling, what's that?
You would want peak horsepower in that range. Where in the range would depend on if you need more grunt off the corner, or if you need a little speed at the end of the straight.
Huh
Kinda sounds like the reason for this thread.
You are kinda on the right track.
I would consider the engines normal powerband to be between peak torque and peak horsepower. So over rev a little to make sure you are using all the work your engine can do.
Below peak torque, any load you add will also lower rpm, dropping torque. Adding load above peak horsepower will drop rpm, but torque will rise.
Might have gave away the farm there.
Last edited: