Why can't diesel make more power than gasoline?
08-01-2007, 04:20 PM
#61
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Originally Posted by mark kibort
As soon as you find away to apply a power, that includes a net force at the rear wheels at 0 velocity, you might experience it. 
Originally Posted by mark kibort
This is why both the A=F/m and A=power/(mass x velocity) can be used. It is the force at the rear wheels that will accelerate the mass (car). power will dictate this. Ive never suggested that power, not force , is what accelerates the mass. Ive said, very clearly, that power determines the force that will accelerate the car.
[/QUOTE]
at 0 speed, you dump the 500hp to the wheels, do you ever have 500hp or the 10,000ft-lbs of torque at the wheels ? if you could, you would have infinite acceleration. but, then again, if you are accelerating, you are not stationary.
[/QUOTE]
if you could get tire to handle that amount of torque then you would get few g's of accelration far from infinite. your "if you are accelerating, you are not stationary.
" highlights your confusion about initial conidtions/states of a dynamical system.[/QUOTE]
You are arguing regarding a newtonian identity. if you want to question it to understand it better, thats ok, ask away.
[/QUOTE]
i do ok with what i know but thank you for the offer.
[/QUOTE]
so, to better understand it. think of two cars both with infinitely variable gear boxes. lets continue to use the 12,000rpm 250ft-lbs but 500hp engine vs the 6000rpm, 500ft-lb 500hp engine. Both rev the engines up to max HP rpm and dump the clutch. assuming NO wheel spin, both will have the exact same torque at the rear wheels, meaning that both will accelerate at the same rate.
If you truely have an infintely variable gear box ( kind of impossible), the moment the clutch is dropped, you would have trememdous acceleration, however, due to Newtonian laws, it would fall porportionate with velocity.
[/QUOTE]
so a car that has 250ft-lbs at 12k rpm and a car that has 500ft-lbs at 6000rpm both would have the same TORQUE at their max rpm ?????????????? same power at that point yes but not torque. the "initial" acceleration would be different assuming same gearing and no slip at the tires.
[/QUOTE]
[/QUOTE]
acceleration = power/(mass x velocity)
it means acceleration is proportional to power and inversely proportional to velocity. but, you have to look at the power applied at the wheels. it means grip cant be a variable. This the part that you and KrC2S are missing
Mk[/QUOTE]
see above
08-01-2007, 04:37 PM
#62
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Originally Posted by krC2S
if i am pushing a block of mass with constant force it has constant acceleration but an increasing velocity..very simple
Originally Posted by krC2S
2-">I'M glad you asked. its really QUITE simple. hp determines torque at the rear wheels. just do a simple test. take 500hp. (both engines, but in the same car with same spaced gear boxes). one engine has 250ft-lbs of peak torque, the other 500ft-lbs of peak torque do all the math you have quoted and tell me the torque at the rear wheels at ANY vehicle speed.
you will find that both will have the same torque at the rear tires ,as mulltiplied through the gear box."
sorry that's wrong torque at the real wheels is just crank torque times an effective transmission ratio which you say is the same so with different crank torques we have different wheel torques
you will find that both will have the same torque at the rear tires ,as mulltiplied through the gear box."
sorry that's wrong torque at the real wheels is just crank torque times an effective transmission ratio which you say is the same so with different crank torques we have different wheel torques
08-01-2007, 04:46 PM
#63
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Originally Posted by insite
in order to maintain a constant force on an accelerating block, you would be increasing your power output. acceleration is inverse to velocity if you hold power constant.
you're thinking in terms of statics again. if the car is stationary, you are correct. the car, however, is moving. because the vehicle's moving, equal power would be required to have equal force at the wheels. the only way a 250lb-ft motor can push as hard as a 500 lb-ft motor at the same vehicle speed is if it is spinning twice as fast (equal power).
you're thinking in terms of statics again. if the car is stationary, you are correct. the car, however, is moving. because the vehicle's moving, equal power would be required to have equal force at the wheels. the only way a 250lb-ft motor can push as hard as a 500 lb-ft motor at the same vehicle speed is if it is spinning twice as fast (equal power).
think of running a car on a dyno..it's no moving but you are making power!
the reaon is that actual power is defined in terms of torque at the crank and angular speed at the crank and similarly for torque and angular speed at the wheel
when the car is moving then we can ususally ( no slip) relate wheel angular speed to car speed
08-01-2007, 04:50 PM
#64
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Originally Posted by doc2s
so a car that has 250ft-lbs at 12k rpm and a car that has 500ft-lbs at 6000rpm both would have the same TORQUE at their max rpm ?????????????? same power at that point yes but not torque. the "initial" acceleration would be different assuming same gearing and no slip at the tires.
each car would be making 571HP. one HP is 550ft-lbs of work per second. if each is capable of working at the same rate (314,166 ft-lb / sec), then each is capable of moving an equivalent mass (say 3,000lb) over the same distance in the same amount of time. this means that the forces at the wheels are equivalent (again, given equivalent gearing).
08-01-2007, 04:53 PM
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Originally Posted by krC2S
no insite it's not statics it's dynamics but of the crank/flywheel angular motion and torque applied there and that generates power even if the car is not moving
think of running a car on a dyno..it's no moving but you are making power!
the reaon is that actual power is defined in terms of torque at the crank and angular speed at the crank and similarly for torque and angular speed at the wheel
when the car is moving then we can ususally ( no slip) relate wheel angular speed to car speed
think of running a car on a dyno..it's no moving but you are making power!
the reaon is that actual power is defined in terms of torque at the crank and angular speed at the crank and similarly for torque and angular speed at the wheel
when the car is moving then we can ususally ( no slip) relate wheel angular speed to car speed
08-01-2007, 04:59 PM
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Originally Posted by insite
if the engine is hooked to a dyno AND the engine is actually on, then it is making power! it is also moving! it may be angular motion, but it is still motion. you can't have power without motion. the very definition of the word power REQUIRES motion to occur.
08-01-2007, 05:02 PM
#67
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Originally Posted by insite
they would have the same WHEEL torque at their max RPM (given equivalent gearing). the 250ft-lb converts its extra motion to work. think of it this way:
so if the last two terms are the same for both vehicles. then wheel torque is not the same. power on the other hand is the same because you have 1/2 the torque but twice the engine speed assuming the same losses in the drive train.
08-01-2007, 05:04 PM
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a tale of two farmers:
two pumpkin farmers each have 100 pumpkins that weigh 50lbs each. the farmers must each move ALL of their pumpkins from one end zone of a football field to the other.
one farmer is a hyper, wiry little guy. the other is big and burly.
the burly farmer carries his pumpkins across the field two at a time. it takes him thirty seconds to cross the field with his pumpkins and he teleports back to get more pumpkins.
the wiry farmer carries his one at a time, but he RUNS accross the field in fifteen seconds before teleporting back to get more.
who finishes first? they finish at the same time. they have done the same work in the same time, so they have exhibited the same rate of work (power). the little guy made up for his lack of might with extra motion (call him Mr. RPM). the big guy made up for his slower speed with sheer force (call him Mr. Torque).
at the end of the day, these guys were equivalent. the same is true in the 250ft-lb / 12K motor vs. 500ft-lb / 6K motor scanario posted earlier.
two pumpkin farmers each have 100 pumpkins that weigh 50lbs each. the farmers must each move ALL of their pumpkins from one end zone of a football field to the other.
one farmer is a hyper, wiry little guy. the other is big and burly.
the burly farmer carries his pumpkins across the field two at a time. it takes him thirty seconds to cross the field with his pumpkins and he teleports back to get more pumpkins.
the wiry farmer carries his one at a time, but he RUNS accross the field in fifteen seconds before teleporting back to get more.
who finishes first? they finish at the same time. they have done the same work in the same time, so they have exhibited the same rate of work (power). the little guy made up for his lack of might with extra motion (call him Mr. RPM). the big guy made up for his slower speed with sheer force (call him Mr. Torque).
at the end of the day, these guys were equivalent. the same is true in the 250ft-lb / 12K motor vs. 500ft-lb / 6K motor scanario posted earlier.
08-01-2007, 05:06 PM
#69
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You still are missing the point.
the rear wheel torque at ANY vehicle speed will be dictated by power. sure, the result of the power is going to be some torque curve on a engine. it can be a curve at high rpms with low torque values, or lower rpms with high torque values. BUT, at any vehicle speed, if the power is the same, the acceleration rate will be the same and to your fight, yes, the REAR wheel torque, after all the gear reductions, will be the same too. I still dont think you understand this.
I am not telling you anything that you probably dont know from your high school studies. However, now we are talking the application of that knowledge that can be a different animal. You still dont understand how two cars with two different engines , (one with twice the engine torque as the other) can produce the same rear wheel torque as multiplied through the gear box at ANY vehicle speed? This is the key to understanding the entire discussion.
you make a comment below about pushing a block with constant force.
if you could do this, power would go up proportional to velocity. See how simple that is?
I think the root of the issue is that you lack the acceptance that it all starts with energy. energy, or potential energy (like in a lump of coal or a gallon of gas) dictates the work that can be done. think HP-seconds or even killowatt-hours like in you home electric bill. the potential energy can produce tremedous power for an instant, or a little power for a long time. the power, or rate of doing work, determines how fast something (a mass) can accelerate.
the torque or forces are dictated by the power, or energy available, and in a gallon of gas or diesel, it is relatively known. lets not even get into efficiency right now, as you know , our engines are very inefficient. if you do work real fast, you accelerate at a rapid rate.
now for your #2. You are not reading carefully enough. i never said same transmissions, I said equal gear spacings. this means that the two 500hp engine powered cars will have the exact same torque at the rear wheels as multiplied through the gear box at ANY vehicle speed.
Since you have said, "your wrong" twice, let me show you why it is not wrong and you need to think a little more about this.
at 100mph, both in 3rd gear, one at a 5:1 ratio, the other at a 10:1 ratio because the 250ft-lb engine revs to 12,000rpm and the 500ft-lb engine revs to 6000rpm. the net force at the rear wheels would be the same. why? because the power dictates the rear wheel torque as measured at the rear wheels through the gear box reductions, regardless of engine torque. (assuming same shaped hp curve)
so, who is not "Cearly Understanding things"?
what are you trying to help me understand???
mk
the rear wheel torque at ANY vehicle speed will be dictated by power. sure, the result of the power is going to be some torque curve on a engine. it can be a curve at high rpms with low torque values, or lower rpms with high torque values. BUT, at any vehicle speed, if the power is the same, the acceleration rate will be the same and to your fight, yes, the REAR wheel torque, after all the gear reductions, will be the same too. I still dont think you understand this.
I am not telling you anything that you probably dont know from your high school studies. However, now we are talking the application of that knowledge that can be a different animal. You still dont understand how two cars with two different engines , (one with twice the engine torque as the other) can produce the same rear wheel torque as multiplied through the gear box at ANY vehicle speed? This is the key to understanding the entire discussion.
you make a comment below about pushing a block with constant force.
if you could do this, power would go up proportional to velocity. See how simple that is?
I think the root of the issue is that you lack the acceptance that it all starts with energy. energy, or potential energy (like in a lump of coal or a gallon of gas) dictates the work that can be done. think HP-seconds or even killowatt-hours like in you home electric bill. the potential energy can produce tremedous power for an instant, or a little power for a long time. the power, or rate of doing work, determines how fast something (a mass) can accelerate.
the torque or forces are dictated by the power, or energy available, and in a gallon of gas or diesel, it is relatively known. lets not even get into efficiency right now, as you know , our engines are very inefficient. if you do work real fast, you accelerate at a rapid rate.
now for your #2. You are not reading carefully enough. i never said same transmissions, I said equal gear spacings. this means that the two 500hp engine powered cars will have the exact same torque at the rear wheels as multiplied through the gear box at ANY vehicle speed.
Since you have said, "your wrong" twice, let me show you why it is not wrong and you need to think a little more about this.
at 100mph, both in 3rd gear, one at a 5:1 ratio, the other at a 10:1 ratio because the 250ft-lb engine revs to 12,000rpm and the 500ft-lb engine revs to 6000rpm. the net force at the rear wheels would be the same. why? because the power dictates the rear wheel torque as measured at the rear wheels through the gear box reductions, regardless of engine torque. (assuming same shaped hp curve)
so, who is not "Cearly Understanding things"?
what are you trying to help me understand???
mk
Originally Posted by krC2S
i will only make two comments now
1- you are arguing newton law and physics and not how the torque curve of car will be or that of a rocket
so your claim that newton law as you re-write it suggests that acceleration is inversly proportional to velocity is just wrong!
if i am pushing a block of mass with constant force it has constant acceleration
but an increasing velocity..very simple
2-">I'M glad you asked. its really QUITE simple. hp determines torque at the rear wheels. just do a simple test. take 500hp. (both engines, but in the same car with same spaced gear boxes). one engine has 250ft-lbs of peak torque, the other 500ft-lbs of peak torque do all the math you have quoted and tell me the torque at the rear wheels at ANY vehicle speed.
you will find that both will have the same torque at the rear tires ,as mulltiplied through the gear box."
sorry that's wrong torque at the real wheels is just crank torque times an effective transmission ratio which you say is the same so with different crank torques we have different wheel torques
i just wanted to help you understand some of these things better but you clearly don't want to try
1- you are arguing newton law and physics and not how the torque curve of car will be or that of a rocket
so your claim that newton law as you re-write it suggests that acceleration is inversly proportional to velocity is just wrong!
if i am pushing a block of mass with constant force it has constant acceleration
but an increasing velocity..very simple
2-">I'M glad you asked. its really QUITE simple. hp determines torque at the rear wheels. just do a simple test. take 500hp. (both engines, but in the same car with same spaced gear boxes). one engine has 250ft-lbs of peak torque, the other 500ft-lbs of peak torque do all the math you have quoted and tell me the torque at the rear wheels at ANY vehicle speed.
you will find that both will have the same torque at the rear tires ,as mulltiplied through the gear box."
sorry that's wrong torque at the real wheels is just crank torque times an effective transmission ratio which you say is the same so with different crank torques we have different wheel torques
i just wanted to help you understand some of these things better but you clearly don't want to try
08-01-2007, 05:07 PM
#70
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Originally Posted by doc2s
wheel torque = crank torque x transmission gear ratio x differential gear ratio.
so if the last two terms are the same for both vehicles. then wheel torque is not the same. power on the other hand is the same because you have 1/2 the torque but twice the engine speed assuming the same losses in the drive train.
so if the last two terms are the same for both vehicles. then wheel torque is not the same. power on the other hand is the same because you have 1/2 the torque but twice the engine speed assuming the same losses in the drive train.
08-01-2007, 05:15 PM
#71
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NET force. at any point in time where there is a net force appliced their will be acceleration. as the force applied from 0 to something, acceleration will start from 0 to something. they are tied together. sitting on a chair, there is a force and no movement, because the chair is acting against the force to an equal level. no NET force, no movment, no acceleration. pull the chair out, you start to fall based on gravity's force. as you fall the kinetic energy goes up with velocity unitl impact where the power at that moment would equal the potential energy stored in your body before the chair was pulled.
Its not that complicated, you are thinking too hard!
mk
Its not that complicated, you are thinking too hard!
mk
Originally Posted by doc2s
you must have a non zero net force to be able to accelerate the vehichle from rest otherwise the vehichle will stay still
A=F/m and power = F x V (velocity). to accelerate an object from rest you must have a non zero net force acting on it and hence you would have a non zero "initial" acceleration while your "initial velocity is zero. the "initial power is zero also since velocity is zero and force is non zero. you claim "that power determines the force" how come zero "initial" power results in a non zero force !!!!! your causality is twisted.
see above
A=F/m and power = F x V (velocity). to accelerate an object from rest you must have a non zero net force acting on it and hence you would have a non zero "initial" acceleration while your "initial velocity is zero. the "initial power is zero also since velocity is zero and force is non zero. you claim "that power determines the force" how come zero "initial" power results in a non zero force !!!!! your causality is twisted.
see above
08-01-2007, 05:20 PM
#72
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Originally Posted by murphyslaw1978
Ahh, yea, now we're getting somewhere. So now we're thinking in terms of limitations by the injection system. The interesting thing is that we're starting to see direct injection in performance engines and HCCI is coming around the corner. You can bet that engineers are already looking at ways to make injection faster/better/more precise. They may still be injecting fuel well before TDC, even in direct injection, and have plenty of time to do so. When you look at the limitation of HCCI, it's mostly due to the injection system, so they are trying to circumvent these limitations by adjusting things like:
Variable compression ratio
Variable induction temperature
Variable exhaust gas percentage
Variable valve actuation
If someone can invent an injection system that can inject fuel at just the right moment at 8000RPM, then we've got a serious solution on our hands, because we've been able to build our engine materials up enough to withstand the kind of power that sort of engine would generate.
Variable compression ratio
Variable induction temperature
Variable exhaust gas percentage
Variable valve actuation
If someone can invent an injection system that can inject fuel at just the right moment at 8000RPM, then we've got a serious solution on our hands, because we've been able to build our engine materials up enough to withstand the kind of power that sort of engine would generate.
research has been going on for some time on using piezoelectric and magnetostrictive materials for injectors. the promise is very fast response time and ability to work with increase fuel pressure. piezo-based injectors are already available. the requirement for fuel delivery in a diesel engine are more stringent than in a direct injection gasoline engine but i'm sure we will see a continuous increase in engine speeds of diesel engine.
08-01-2007, 05:21 PM
#73
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Originally Posted by insite
the last two terms AREN'T the same. when i said equivalent gearboxes, i meant that each was designed to take full advantage of the motor it's attached to. miscommunication.
08-01-2007, 05:32 PM
#74
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im glad you brought up dynos. And i hope at the end of this you finally admit that you do know about how to calcualte HP with torque and RPMs, but didnt fully understand the relatioship of power to the accelerative forces.
Do you now see how the 6000rpm, 500max torque 500hp engine can make the same torque at the driven wheels at ANY vehicle speed compared to the same 500hp 12,000rpm engine with 250ft-lbs of engine torque?
all you needed to do was calcualte the torque using the equation you seem to be so versed in. it would have yeilded the same torque at the rear tires at any speed, in my question to you, it was 40mph.
Now, for the dyno. do you know what a dyno actually is measureing. ever do a dyno run on a rolling dyno that didnt have a spark signal? whats the output? you get HP and MPH. what about enging torque????? well, how does a dyno know? all it sees is that the drums are accelerated over a speed range. since, POWER is the change of kinetic energy, it can easily produce power curves. It could also have a torque curve, but it would be something we wouldnt understand as it would be torque values that have been multiplied through the gear box and rear end ratios. Its not until the dyno gets the rpm signal from the spark is it able to give you engine torque values.
this dyno wouldnt know if the 450rwhp is from a 911 RSR or a Viper. all it would be able to tell us is HP over a speed range. Now, plug in the spark signal and watch the 9000rpm porsche give only 270ft-lbs of torque, while the 5800rpm viper produces 550ft-lbs peak, however the dyno just showed you that both have the same accelerative forces at the rear tires!
mk
Do you now see how the 6000rpm, 500max torque 500hp engine can make the same torque at the driven wheels at ANY vehicle speed compared to the same 500hp 12,000rpm engine with 250ft-lbs of engine torque?
all you needed to do was calcualte the torque using the equation you seem to be so versed in. it would have yeilded the same torque at the rear tires at any speed, in my question to you, it was 40mph.
Now, for the dyno. do you know what a dyno actually is measureing. ever do a dyno run on a rolling dyno that didnt have a spark signal? whats the output? you get HP and MPH. what about enging torque????? well, how does a dyno know? all it sees is that the drums are accelerated over a speed range. since, POWER is the change of kinetic energy, it can easily produce power curves. It could also have a torque curve, but it would be something we wouldnt understand as it would be torque values that have been multiplied through the gear box and rear end ratios. Its not until the dyno gets the rpm signal from the spark is it able to give you engine torque values.
this dyno wouldnt know if the 450rwhp is from a 911 RSR or a Viper. all it would be able to tell us is HP over a speed range. Now, plug in the spark signal and watch the 9000rpm porsche give only 270ft-lbs of torque, while the 5800rpm viper produces 550ft-lbs peak, however the dyno just showed you that both have the same accelerative forces at the rear tires!
mk
Originally Posted by krC2S
no insite it's not statics it's dynamics but of the crank/flywheel angular motion and torque applied there and that generates power even if the car is not moving
think of running a car on a dyno..it's no moving but you are making power!
the reaon is that actual power is defined in terms of torque at the crank and angular speed at the crank and similarly for torque and angular speed at the wheel
when the car is moving then we can ususally ( no slip) relate wheel angular speed to car speed
think of running a car on a dyno..it's no moving but you are making power!
the reaon is that actual power is defined in terms of torque at the crank and angular speed at the crank and similarly for torque and angular speed at the wheel
when the car is moving then we can ususally ( no slip) relate wheel angular speed to car speed
08-01-2007, 05:33 PM
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1."you make a comment below about pushing a block with constant force.
if you could do this, power would go up proportional to velocity. See how simple that is?"
sure but that has nothing to do with your statament which you repeated many times as a general newtonian thing (forget cars) is that " acceleration is inversly proporional to speed." which is still wrong!
2. sorry i misread your statemnt so different ratios but same spacing..so what's the argument then?
it's obvious without even looking at power and rpm!
torque at wheel=crank torque X transmission ratio
so torque at wheels =250X 10= 500X5
this is true regardless of how much power we will make ( different redlines etc)
if you could do this, power would go up proportional to velocity. See how simple that is?"
sure but that has nothing to do with your statament which you repeated many times as a general newtonian thing (forget cars) is that " acceleration is inversly proporional to speed." which is still wrong!
2. sorry i misread your statemnt so different ratios but same spacing..so what's the argument then?
it's obvious without even looking at power and rpm!
torque at wheel=crank torque X transmission ratio
so torque at wheels =250X 10= 500X5
this is true regardless of how much power we will make ( different redlines etc)
Originally Posted by mark kibort
You still are missing the point.
the rear wheel torque at ANY vehicle speed will be dictated by power. sure, the result of the power is going to be some torque curve on a engine. it can be a curve at high rpms with low torque values, or lower rpms with high torque values. BUT, at any vehicle speed, if the power is the same, the acceleration rate will be the same and to your fight, yes, the REAR wheel torque, after all the gear reductions, will be the same too. I still dont think you understand this.
I am not telling you anything that you probably dont know from your high school studies. However, now we are talking the application of that knowledge that can be a different animal. You still dont understand how two cars with two different engines , (one with twice the engine torque as the other) can produce the same rear wheel torque as multiplied through the gear box at ANY vehicle speed? This is the key to understanding the entire discussion.
you make a comment below about pushing a block with constant force.
if you could do this, power would go up proportional to velocity. See how simple that is?
I think the root of the issue is that you lack the acceptance that it all starts with energy. energy, or potential energy (like in a lump of coal or a gallon of gas) dictates the work that can be done. think HP-seconds or even killowatt-hours like in you home electric bill. the potential energy can produce tremedous power for an instant, or a little power for a long time. the power, or rate of doing work, determines how fast something (a mass) can accelerate.
the torque or forces are dictated by the power, or energy available, and in a gallon of gas or diesel, it is relatively known. lets not even get into efficiency right now, as you know , our engines are very inefficient. if you do work real fast, you accelerate at a rapid rate.
now for your #2. You are not reading carefully enough. i never said same transmissions, I said equal gear spacings. this means that the two 500hp engine powered cars will have the exact same torque at the rear wheels as multiplied through the gear box at ANY vehicle speed.
Since you have said, "your wrong" twice, let me show you why it is not wrong and you need to think a little more about this.
at 100mph, both in 3rd gear, one at a 5:1 ratio, the other at a 10:1 ratio because the 250ft-lb engine revs to 12,000rpm and the 500ft-lb engine revs to 6000rpm. the net force at the rear wheels would be the same. why? because the power dictates the rear wheel torque as measured at the rear wheels through the gear box reductions, regardless of engine torque. (assuming same shaped hp curve)
so, who is not "Cearly Understanding things"?
what are you trying to help me understand???
mk
the rear wheel torque at ANY vehicle speed will be dictated by power. sure, the result of the power is going to be some torque curve on a engine. it can be a curve at high rpms with low torque values, or lower rpms with high torque values. BUT, at any vehicle speed, if the power is the same, the acceleration rate will be the same and to your fight, yes, the REAR wheel torque, after all the gear reductions, will be the same too. I still dont think you understand this.
I am not telling you anything that you probably dont know from your high school studies. However, now we are talking the application of that knowledge that can be a different animal. You still dont understand how two cars with two different engines , (one with twice the engine torque as the other) can produce the same rear wheel torque as multiplied through the gear box at ANY vehicle speed? This is the key to understanding the entire discussion.
you make a comment below about pushing a block with constant force.
if you could do this, power would go up proportional to velocity. See how simple that is?
I think the root of the issue is that you lack the acceptance that it all starts with energy. energy, or potential energy (like in a lump of coal or a gallon of gas) dictates the work that can be done. think HP-seconds or even killowatt-hours like in you home electric bill. the potential energy can produce tremedous power for an instant, or a little power for a long time. the power, or rate of doing work, determines how fast something (a mass) can accelerate.
the torque or forces are dictated by the power, or energy available, and in a gallon of gas or diesel, it is relatively known. lets not even get into efficiency right now, as you know , our engines are very inefficient. if you do work real fast, you accelerate at a rapid rate.
now for your #2. You are not reading carefully enough. i never said same transmissions, I said equal gear spacings. this means that the two 500hp engine powered cars will have the exact same torque at the rear wheels as multiplied through the gear box at ANY vehicle speed.
Since you have said, "your wrong" twice, let me show you why it is not wrong and you need to think a little more about this.
at 100mph, both in 3rd gear, one at a 5:1 ratio, the other at a 10:1 ratio because the 250ft-lb engine revs to 12,000rpm and the 500ft-lb engine revs to 6000rpm. the net force at the rear wheels would be the same. why? because the power dictates the rear wheel torque as measured at the rear wheels through the gear box reductions, regardless of engine torque. (assuming same shaped hp curve)
so, who is not "Cearly Understanding things"?
what are you trying to help me understand???
mk