yoshimitsuspeed wrote:This would be no different with power. You would need the graph to have torque and RPM to make it of any use and once you have those two things you have everything you need to determine power. You could look at either torque or power and know just as much. Any way you cut it I am not talking about tuning. I am talking about acceleration potential. I am showing that a motor with huge cams can make the same in the low to mid range as a build with smaller cams. The dynos are right there. It's hard to make out the power graph on the N2 build but it's there. I posted the power for a few spots for reference. Since you have HP and RPM you can calculate FW torque if you want to know but it's irrelevant to the topic at hand. If the poncam motor makes 20% more power at 3k RPM then it will make 20% more torque there too.
When I ask the question "at what RPM is VE highest?" and hand you a power with respect to RPM graph, you would have to do some calculations. If I asked you with a torque graph you would just point to peak torque and say, "There." Seeing changes in that peak, or in the shape of the curve, is important, and conveys much more information about how an engine behaves than power.
yoshimitsuspeed wrote:It still does.
I could show you a torque graph of a motor that makes 100 lb ft at 100 RPM and a motor that makes 100 lb ft at 200 RPM. As long as they were scaled properly without RPM markers they would look identical even though one motor did twice as much work per unit of time.
I didn't phrase that correctly, so you are right here. Adding RPM to the equation, that is using power instead of torque, would be less productive than torque for the above mentioned reason.
burdickjp wrote:F = M * A
T = F * r
F = force
M = mass
A = acceleration
T = torque
r = radius of lever arm
T / r = M * A = 907 * 2 = 1814 N*m /m
So 1814 N applied to a 1m arm or 907 N applied to a 2m arm, etc.
yoshimitsuspeed wrote:This equation is incomplete. It does not address time.
I'm at a loss as to why you'd be arguing against Newton's Second Law.
I'm going to go ahead and repeat it with units so you can see that it works.
T / r = M * A
N*m / m = kg * m/s^2
N = kg * m/s^2
kg * m/s^2 = kg * m/s^2
All units cancel. It's a good equation.
You can apply 1814 NM to a lever but if it's not moving it's not doing any work. You need to move to have work and you need to calculate that work over time to calculate power.
We can also look at this in the linear manner. http://www.epi-eng.com/mechanical_engin ... d_work.htm
You can push on your car as hard as you can but if it does not move it's not doing any work.
F = M * A still applies. Force causes motion.
Unless there's an opposing force. In the case of the immobile car, that would be friction. You have to overcome friction to start motion. The equation then becomes:
Force - friction = mass * acceleration
Acceleration is then proportional to NET force, or really, the summation of ALL net forces on the object. You've got a bunch of forces on an object, which way does it accelerate? That is determined by the resultant of the forces. This is the basis of dynamics.
yoshimitsuspeed wrote:To determine how fast something will accelerate you need to determine the amount of work that can be done over time. Or the rate of acceleration.
The force, be it linear or rotational does not mean anything until you define the rate at which it applies that force and does work.
F = M * A
yoshimitsuspeed wrote:Let's go back to the link comparing work and energy. Here We need to clarify the difference between a lb/ft and a ft/lb as they are completely different measurements.
A lb/ft is a force applied. That force doesn't have to move and doesn't have to do any work. A lb/ft is the ability to apply one lb of force for the distance of one foot. This is a measurement of work. It still cannot calculate acceleration because it still doesn't factor for time. Now if you apply 1 lb of force 1 foot in one second you can now calculate accleration. Once again we are back to talking about work over time or power.
A lb/ft is a linear density. A pound per foot.
A ft/lb is a specific length. A foot per pound.
A lb*ft or ft*lb is what you are trying to talk about.
yoshimitsuspeed wrote:Acceleration is 100% proportional to power.
Once again acceleration is a measure of speed over time.
Acceleration is NOT proportional to power. It is proportional to force in rectilinear systems and torque in rotational systems. That is Newton's Second Law. F = M * A
Acceleration is the first derivative of velocity with respect to time. It is the measure of a CHANGE in speed with respect to time.
yoshimitsuspeed wrote:On the other side of the equation you need time. Force applied needs to be factored over time. This brings us back to power.
Force over time is not power.