Drivetrain Losses
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Drivetrain Losses Interestingly enough, HPtuners logs engine torque on LS2/LS7 motors. I noticed this some time ago and started logging it a while back. I never really paid to much attention to this since the cars are on our dyno, so I have my HP and TQ reading right there. Today I'm playing around with a 06 Z06. On our Mustang MD-1100SE dyno, it made 431.8rwtq (horrible weather in chicagoland today, hot and humid), and yet the torque reading in the scan read 533lbs/tq. That's 101.2lbs/tq loss through the drivetrain, or 19%. Assuming that the torque reading in the scanner is accurate, it kind of ruins the 15-17% drivetrain loss that is currently accepted for manual transmissions.
Originally Posted by Tuner@Straightline
Interestingly enough, HPtuners logs engine torque on LS2/LS7 motors. I noticed this some time ago and started logging it a while back. I never really paid to much attention to this since the cars are on our dyno, so I have my HP and TQ reading right there. Today I'm playing around with a 06 Z06. On our Mustang MD-1100SE dyno, it made 431.8rwtq (horrible weather in chicagoland today, hot and humid), and yet the torque reading in the scan read 533lbs/tq. That's 101.2lbs/tq loss through the drivetrain, or 19%. Assuming that the torque reading in the scanner is accurate, it kind of ruins the 15-17% drivetrain loss that is currently accepted for manual transmissions.
Hi Tuner@Straightline
I started a thread mid February on the HP Tuner Forum (3 pages/50 posts a lot of screenshots) regarding the Torque Histogram here:
http://www.hptuners.com/forum/showthread.php?t=10401
At the end it becomes clear that this device is useless because inaccurate.
Christian
Originally Posted by Tuner@Straightline
Interestingly enough, HPtuners logs engine torque on LS2/LS7 motors. I noticed this some time ago and started logging it a while back. I never really paid to much attention to this since the cars are on our dyno, so I have my HP and TQ reading right there. Today I'm playing around with a 06 Z06. On our Mustang MD-1100SE dyno, it made 431.8rwtq (horrible weather in chicagoland today, hot and humid), and yet the torque reading in the scan read 533lbs/tq. That's 101.2lbs/tq loss through the drivetrain, or 19%. Assuming that the torque reading in the scanner is accurate, it kind of ruins the 15-17% drivetrain loss that is currently accepted for manual transmissions.
Not really.
Maybe your dyno reads low?
This is really a useless debate that can never be answered correctly. oponions are all we have and facts are impossible.
drivetrain loss depends on how effecient yours is.stock probably around 16 -17% for a m6,heavy brakes,heavy wheels ,ect.Now lightweight gundrilled axels,spool,strange brakes,carbonfiber drive shaft-somewhere around 12-14%
Drivetrain loss is not a percentage across the board. Even after all the posts, everyone still thinks this is the case.
How in the world can you make more power, and lose more power when you are accelerating the same masses with the same inertia.
Once again, refer to the search button at the top of the page and you will see Tony Mamo's gain on an engine dyno of 60 hp show up 60 hp on a chassis dyno, giving the same exact drvietrain loss.
Also, the torque calculation is not accurate. It varies with airflow, timing, ect. My moms Grand Am said 270 ft-lbs on a stock v6, and my car said 450 ft-lbs and I dyno 437 ft-lbs. You can not go by this at all. Also, this parameter is can be logged on many cars. Bottom line here is the only thing that matters is what the car puts to the ground. Anyone trying to advertise engine hp as what they make need a swift kick in the nuts. That is like saying, oh my car would run 7's if it were 1500 lbs lighter. It is what it is.
How in the world can you make more power, and lose more power when you are accelerating the same masses with the same inertia.
Once again, refer to the search button at the top of the page and you will see Tony Mamo's gain on an engine dyno of 60 hp show up 60 hp on a chassis dyno, giving the same exact drvietrain loss.
Also, the torque calculation is not accurate. It varies with airflow, timing, ect. My moms Grand Am said 270 ft-lbs on a stock v6, and my car said 450 ft-lbs and I dyno 437 ft-lbs. You can not go by this at all. Also, this parameter is can be logged on many cars. Bottom line here is the only thing that matters is what the car puts to the ground. Anyone trying to advertise engine hp as what they make need a swift kick in the nuts. That is like saying, oh my car would run 7's if it were 1500 lbs lighter. It is what it is.
Last edited by WS6FirebirdTA00; Jun 3, 2007 at 03:25 PM.
In the thread mentioned above on HP Tuner Forum from the post #32 you can read about drivetrain loss as well:
http://www.hptuners.com/forum/showpo...0&postcount=32
And my post below will bring you directely to Tony Mamo thread about the subject:
http://www.hptuners.com/forum/showpo...5&postcount=38
Christian
http://www.hptuners.com/forum/showpo...0&postcount=32
And my post below will bring you directely to Tony Mamo thread about the subject:
http://www.hptuners.com/forum/showpo...5&postcount=38
Christian
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Well, how about someone that has the time take an engine to an engine dyno and measure the power from the crank and compare it to what the data logger says, then run it on a chasis dyno and calculate the drivetrain loss from that? That would settle all debates on drivetrain loss, and the data logger accuracy.
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Originally Posted by RocketCutlass
Well, how about someone that has the time take an engine to an engine dyno and measure the power from the crank and compare it to what the data logger says, then run it on a chasis dyno and calculate the drivetrain loss from that? That would settle all debates on drivetrain loss, and the data logger accuracy.
All those procedures are pretty well described with the correct measurements and for the Torque Histogram the final conclusion.
Christian
Originally Posted by Tuner@Straightline
I was more or less interested in how accurate it could be. I usually go by what my dyno tells me, and thought that the 100lbs of torque loss seemed high.
Originally Posted by RocketCutlass
Well, how about someone that has the time take an engine to an engine dyno and measure the power from the crank and compare it to what the data logger says, then run it on a chasis dyno and calculate the drivetrain loss from that? That would settle all debates on drivetrain loss, and the data logger accuracy.
Originally Posted by WS6FirebirdTA00
It has been done, just no one searches for it.
Some work has been done on HP Tuner Forum about that, remember well...
I mention in my post above the references:
Please reread the post #2 & #7.
All those procedures are pretty well described with the correct measurements and for the Torque Histogram the final conclusion.
Christian
Originally Posted by WS6FirebirdTA00
Drivetrain loss is not a percentage across the board. Even after all the posts, everyone still thinks this is the case.
How in the world can you make more power, and lose more power when you are accelerating the same masses with the same inertia.
Once again, refer to the search button at the top of the page and you will see Tony Mamo's gain on an engine dyno of 60 hp show up 60 hp on a chassis dyno, giving the same exact drvietrain loss.
Also, the torque calculation is not accurate. It varies with airflow, timing, ect. My moms Grand Am said 270 ft-lbs on a stock v6, and my car said 450 ft-lbs and I dyno 437 ft-lbs. You can not go by this at all. Also, this parameter is can be logged on many cars. Bottom line here is the only thing that matters is what the car puts to the ground. Anyone trying to advertise engine hp as what they make need a swift kick in the nuts. That is like saying, oh my car would run 7's if it were 1500 lbs lighter. It is what it is.
How in the world can you make more power, and lose more power when you are accelerating the same masses with the same inertia.
Once again, refer to the search button at the top of the page and you will see Tony Mamo's gain on an engine dyno of 60 hp show up 60 hp on a chassis dyno, giving the same exact drvietrain loss.
Also, the torque calculation is not accurate. It varies with airflow, timing, ect. My moms Grand Am said 270 ft-lbs on a stock v6, and my car said 450 ft-lbs and I dyno 437 ft-lbs. You can not go by this at all. Also, this parameter is can be logged on many cars. Bottom line here is the only thing that matters is what the car puts to the ground. Anyone trying to advertise engine hp as what they make need a swift kick in the nuts. That is like saying, oh my car would run 7's if it were 1500 lbs lighter. It is what it is.
correct me if im wrong.... but the more power you make the more power things will flex and bend, thus causing further losses of HP??? at least thats the way id see it.
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drivetrain loss is a percentage not a fixed number
F=ma where force = mass x acceleration already indicates that. Since horsepower is a measure of acceleration in the end. The relationship says if acceleration goes up, so must the force required.
What it comes down to is if you intend to accelerate something faster, it will take more power to increase the acceleration. So x percentage is going to take up power from the engine to turn the mass of the drivetrain. Since you want the car to move faster, thus the drivetrain mass to spin faster, more power will be used in relation to the increase in acceleration of the car.
F=ma where force = mass x acceleration already indicates that. Since horsepower is a measure of acceleration in the end. The relationship says if acceleration goes up, so must the force required.
What it comes down to is if you intend to accelerate something faster, it will take more power to increase the acceleration. So x percentage is going to take up power from the engine to turn the mass of the drivetrain. Since you want the car to move faster, thus the drivetrain mass to spin faster, more power will be used in relation to the increase in acceleration of the car.
Originally Posted by SladeX
drivetrain loss is a percentage not a fixed number
F=ma where force = mass x acceleration already indicates that. Since horsepower is a measure of acceleration in the end. The relationship says if acceleration goes up, so must the force required.
What it comes down to is if you intend to accelerate something faster, it will take more power to increase the acceleration. So x percentage is going to take up power from the engine to turn the mass of the drivetrain. Since you want the car to move faster, thus the drivetrain mass to spin faster, more power will be used in relation to the increase in acceleration of the car.
F=ma where force = mass x acceleration already indicates that. Since horsepower is a measure of acceleration in the end. The relationship says if acceleration goes up, so must the force required.
What it comes down to is if you intend to accelerate something faster, it will take more power to increase the acceleration. So x percentage is going to take up power from the engine to turn the mass of the drivetrain. Since you want the car to move faster, thus the drivetrain mass to spin faster, more power will be used in relation to the increase in acceleration of the car.
You are over-simplifying the equation, I will dig some more up...
Last edited by WS6FirebirdTA00; Jun 4, 2007 at 04:15 PM.
https://ls1tech.com/forums/advanced-engineering-tech/471904-drivetrain-loss-relation-rwhp.html
I understand where you come from on your explanation, but the bottom line is this is not what is actually seen.
I understand where you come from on your explanation, but the bottom line is this is not what is actually seen.
While Im sure its not a linear percentage, it certinaly can not be a fixed number either, at least not for all rpms. Drivetrain might eat 50 HP at 6000 rpm, but when im turning it by hand, im certainly not producing 50 HP.
I guess somebody would need to find out how much power it takes to turn the drivetrain at different RPMs.
I guess somebody would need to find out how much power it takes to turn the drivetrain at different RPMs.
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I never said it was a fixed percentage
There are way too many variations in driveline combos to affix a fixed number. The only true way to know the efficiency of your driveline is to dyno the engine first, then add the drivetrain.
Also to address the hand thing, you can "move" the whole thing by hand, but how many revolutions per minute, how about acceleration of the rpm? Once you get the mass moving, the initial hard push, afterwards all you are doing is overcoming the friction of the components within the lubricants.
To say "15%" is a generalization. A simple change of 16 to 17's can affect that for the worse due to increase or decrease weight (depends on the rim/tire combo). Even fluids will affect the efficiency.
In the end, that simplification is the best way to get the point across to many people. If you want to go faster, more power will be needed and more will be lost to the drivetrain.
There are way too many variations in driveline combos to affix a fixed number. The only true way to know the efficiency of your driveline is to dyno the engine first, then add the drivetrain.
Also to address the hand thing, you can "move" the whole thing by hand, but how many revolutions per minute, how about acceleration of the rpm? Once you get the mass moving, the initial hard push, afterwards all you are doing is overcoming the friction of the components within the lubricants.
To say "15%" is a generalization. A simple change of 16 to 17's can affect that for the worse due to increase or decrease weight (depends on the rim/tire combo). Even fluids will affect the efficiency.
In the end, that simplification is the best way to get the point across to many people. If you want to go faster, more power will be needed and more will be lost to the drivetrain.