441whp = What @ flywheel???
Originally Posted by 01Z28M6
No offense intended but the laws of physics you are not getting. It has to do with coefficients and power consumption ramping up to do a greater task. This is exactly how the properties of physics work in all but quantum mechanics.
For example, the Bugati Veyron can go 150 mph with its first 250 horsepower but it takes the remaining 751 hp to go to the top speed of 252 mph. Your logic is reasonable but it's physics and the dynamics that break the laws of logic; good questions though.
A Google search will get you some math if that's what it takes. Good luck.
For example, the Bugati Veyron can go 150 mph with its first 250 horsepower but it takes the remaining 751 hp to go to the top speed of 252 mph. Your logic is reasonable but it's physics and the dynamics that break the laws of logic; good questions though.
A Google search will get you some math if that's what it takes. Good luck.
good thread though. lots of questions i had are answered here
you tha man! 
Here is how I look at it. The reason it is a percentage is because the more power you throw at the drivetrain, the more is lost due to the drivetrain giving in more due to the lack of stability. If it was in a fixture and all components could not give any at all it would be different but the ENTIRE drivetrain comes into play. Clutchs will slip a little more, tq arms will bend a little more, etc. You can't possibly think that a drivetrain with 1000hp going to it will react and put out as much as a car with 300hp. Think about it LOGICALLY.
Here's what I have noted for figuring hp @ the flywheel.
rwhp X 1.15 (standard)
rwhp X 1.2 (auto)
I found these on here somewhere but I only use them for reference. Because all of the variables already discussed in this thread, I don't see how one formula could fit all set-ups. There are just too many moving parts between the flexplate/flywheel and the dyno rollers to account for. So basically, it would be more time and labor effective to just pull the motor and have it dynoed and subtract the 2 for the difference.
rwhp X 1.15 (standard)
rwhp X 1.2 (auto)
I found these on here somewhere but I only use them for reference. Because all of the variables already discussed in this thread, I don't see how one formula could fit all set-ups. There are just too many moving parts between the flexplate/flywheel and the dyno rollers to account for. So basically, it would be more time and labor effective to just pull the motor and have it dynoed and subtract the 2 for the difference.
Originally Posted by Platinum WS6
Here is how I look at it. The reason it is a percentage is because the more power you throw at the drivetrain, the more is lost due to the drivetrain giving in more due to the lack of stability. If it was in a fixture and all components could not give any at all it would be different but the ENTIRE drivetrain comes into play. Clutchs will slip a little more, tq arms will bend a little more, etc. You can't possibly think that a drivetrain with 1000hp going to it will react and put out as much as a car with 300hp. Think about it LOGICALLY.
damn, talk about over analyzing an ESTIMATE of horsepower.. if you really want to know the flywheel HP.. pull the damn engine.. take it to an engine dyno.. see what it reads.. compair that to the RWHP you have.. do the math.. you have your answer...
sheesh
sheesh
Originally Posted by Screamin_Z
jason99frc:
wow dude, u really want a "mathematical formula"? get a fvckin life. sounds like u need to be hanging out with ur friends in the basement of the science building rather than talking about car **** on this forum.
u just ruined this thread for me, go ahead with ur physics **** cuz I'm thru.
wow dude, u really want a "mathematical formula"? get a fvckin life. sounds like u need to be hanging out with ur friends in the basement of the science building rather than talking about car **** on this forum.
u just ruined this thread for me, go ahead with ur physics **** cuz I'm thru.
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Some dyno shops have some software that has all the % of loss so you can find out! Thats why i asked
About 15% M6 about 18% A4. sounds right
About 15% M6 about 18% A4. sounds right
OK 1 LAST ATTEMPT.
1. There are about 10 different variables which make it impossible to have anything close to exact for a standard formula, with-in 5% if you're lucky.
IE: Converter efficiency, Fluid dynamics with-in the trans and converter, Internal trans parts weights, internal differnetial weights, drive shaft weight, wheel and tire weight, rear gear, rolling resistance, the dyno itself can vary by 3-5 % depending on how recently it was serviced and calibrated......
All I wanted to point out is that there is no one formula or theory or calculation which can guarantee anything with-in 5% accuracy because of all of the variables. In my world an estimation with a 5% variance doesnt make the test/estimation worth while.
And being that so many idiots on here will decide if they made a good purchase because the dyno is 20 rwhp high or low from someone elses car, on someone elses dyno, with different parts from the flywheel back you just cant simply use a set % # with any accuracy.
Physics is physics but you will not know the loss without doing 2 separate tests on you own car. ENGINE DYNO THEN INSTALL AND DO THE CHASSIS
Use 18%/10% what ever, I dont care. I just dont want every young guy coming into this world of performance using estimates as facts which is how too many things on these websites are portrayed.
1. There are about 10 different variables which make it impossible to have anything close to exact for a standard formula, with-in 5% if you're lucky.
IE: Converter efficiency, Fluid dynamics with-in the trans and converter, Internal trans parts weights, internal differnetial weights, drive shaft weight, wheel and tire weight, rear gear, rolling resistance, the dyno itself can vary by 3-5 % depending on how recently it was serviced and calibrated......
All I wanted to point out is that there is no one formula or theory or calculation which can guarantee anything with-in 5% accuracy because of all of the variables. In my world an estimation with a 5% variance doesnt make the test/estimation worth while.
And being that so many idiots on here will decide if they made a good purchase because the dyno is 20 rwhp high or low from someone elses car, on someone elses dyno, with different parts from the flywheel back you just cant simply use a set % # with any accuracy.
Physics is physics but you will not know the loss without doing 2 separate tests on you own car. ENGINE DYNO THEN INSTALL AND DO THE CHASSIS
Use 18%/10% what ever, I dont care. I just dont want every young guy coming into this world of performance using estimates as facts which is how too many things on these websites are portrayed.
Last edited by jason99frc; Aug 22, 2007 at 05:36 PM.
Originally Posted by jason99frc
OK 1 LAST ATTEMPT.
1. There are about 10 different variables which make it impossible to have anything close to exact for a standard formula, with-in 5% if you're lucky.
IE: Converter efficiency, Fluid dynamics with-in the trans and converter, Internal trans parts weights, internal differnetial weights, drive shaft weight, wheel and tire weight, rear gear, rolling resistance, the dyno itself can vary by 3-5 % depending on how recently it was serviced and calibrated......
All I wanted to point out is that there is no one formula or theory or calculation which can guarantee anything with-in 5% accuracy because of all of the variables. In my world an estimation with a 5% variance doesnt make the test/estimation worth while.
And being that so many idiots on here will decide if they made a good purchase because the dyno is 20 rwhp high or low from someone elses car, on someone elses dyno, with different parts from the flywheel back you just cant simply use a set % # with any accuracy.
Physics is physics but you will not know the loss without doing 2 separate tests on you own car. ENGINE DYNO THEN INSTALL AND DO THE CHASSIS
Use 18%/10% what ever, I dont care. I just dont want every young guy coming into this world of performance using estimates as facts which is how too many things on these websites are portrayed.
1. There are about 10 different variables which make it impossible to have anything close to exact for a standard formula, with-in 5% if you're lucky.
IE: Converter efficiency, Fluid dynamics with-in the trans and converter, Internal trans parts weights, internal differnetial weights, drive shaft weight, wheel and tire weight, rear gear, rolling resistance, the dyno itself can vary by 3-5 % depending on how recently it was serviced and calibrated......
All I wanted to point out is that there is no one formula or theory or calculation which can guarantee anything with-in 5% accuracy because of all of the variables. In my world an estimation with a 5% variance doesnt make the test/estimation worth while.
And being that so many idiots on here will decide if they made a good purchase because the dyno is 20 rwhp high or low from someone elses car, on someone elses dyno, with different parts from the flywheel back you just cant simply use a set % # with any accuracy.
Physics is physics but you will not know the loss without doing 2 separate tests on you own car. ENGINE DYNO THEN INSTALL AND DO THE CHASSIS
Use 18%/10% what ever, I dont care. I just dont want every young guy coming into this world of performance using estimates as facts which is how too many things on these websites are portrayed.
Originally Posted by GR33N GoblinM6
damn, talk about over analyzing an ESTIMATE of horsepower.. if you really want to know the flywheel HP.. pull the damn engine.. take it to an engine dyno.. see what it reads.. compair that to the RWHP you have.. do the math.. you have your answer...
sheesh
sheesh
Originally Posted by Screamin_Z
jason99frc:
wow dude, u really want a "mathematical formula"? get a fvckin life. sounds like u need to be hanging out with ur friends in the basement of the science building rather than talking about car **** on this forum.
u just ruined this thread for me, go ahead with ur physics **** cuz I'm thru.
wow dude, u really want a "mathematical formula"? get a fvckin life. sounds like u need to be hanging out with ur friends in the basement of the science building rather than talking about car **** on this forum.
u just ruined this thread for me, go ahead with ur physics **** cuz I'm thru.
Originally Posted by jason99frc
RealQuick,
I think screamin z has left the debate.
I think screamin z has left the debate.
Jon
Originally Posted by Mr.MartyStone
Thank god somebody understands. There is no set percentage even though the forumulas would suggest otherwise. I bet that a 5 speed lenco through a dana 60 loses damn near the same hp behind a 1000 hp BBC as it does a 550 hp ls1.
Look at it this way. Lets hook up a 9" on a direct driveshaft behind a 20 hp B&S and then hook it up behind a 350 hp ls1. do a pull on a chassis dyno. I would be willing to guess that the Briggs motor will use a much higher percentage to turn the tires over than the ls1. It may take more total horsepower behind the ls1 because of the incresed acceleration rate, but I would guess the percentage would be way, way lower..