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## Main Question or Discussion Point

Given the following instantaneous parameters and constants...

d = air density = 1.24

Cr = rolling resistance coeffecient = 0.015

FA = frontal area = 1.48

Cd = drag coefficient = 0.29F

G = gravity (mps2) = 9.80665

pi = 3.1415926

m = vehicle mass (Kg) = 1542

DL = drivetrain loss = .2

V = velocity (m/s)

A = acceleration (m/s/s)

F = vehicle force (KgMps2)

T = Torque (KgM)

HP = horsepower

Tire radius

Current gear and gear ratio

... what would be an equation that would let me estimate instantaneous engine torque (or HP) at the wheels?

So far (I think) I have worked out these terms:

rollDrag = G * Cr * m

airDrag = .5 * Cd * FA * d * V * V

F = (m * A) + airDrag + rollDrag

Assuming that ^ is correct, this is where I'm stuck.

Any help is greatly appreciated. I'm sure I'm just over-thinking it or something, but I've drawn a blank and have been spinning my wheels (so to speak) on this for a couple of days now.

Thanks in advance!

__Known:__d = air density = 1.24

Cr = rolling resistance coeffecient = 0.015

FA = frontal area = 1.48

Cd = drag coefficient = 0.29F

G = gravity (mps2) = 9.80665

pi = 3.1415926

m = vehicle mass (Kg) = 1542

DL = drivetrain loss = .2

V = velocity (m/s)

A = acceleration (m/s/s)

__Unknown:__F = vehicle force (KgMps2)

T = Torque (KgM)

HP = horsepower

Unknown, but can be found if needed:Unknown, but can be found if needed:

Tire radius

Current gear and gear ratio

... what would be an equation that would let me estimate instantaneous engine torque (or HP) at the wheels?

So far (I think) I have worked out these terms:

rollDrag = G * Cr * m

airDrag = .5 * Cd * FA * d * V * V

F = (m * A) + airDrag + rollDrag

Assuming that ^ is correct, this is where I'm stuck.

Any help is greatly appreciated. I'm sure I'm just over-thinking it or something, but I've drawn a blank and have been spinning my wheels (so to speak) on this for a couple of days now.

Thanks in advance!

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