drag raced F1000

[dirkdiggler]

Strictly speaking it is not a function of porting or pipe design timing or other factors. It is a function of the physics involved. The things you listed allow a change in the operating environment but not the physics. To get more horsepower only need to spin the motor up faster (increase the rate at which work is being done). To get more torque you need push on the piston harder (do more work). In general it's easier to get more horsepower than it is to get more torque. You can feel the increase in horsepower because the motor is delivering the available torque faster and that's what gets people excited.

Where the peak measurements occur in the RPM range is effected by the environment created with porting, pipes etc.

That is true and Untrue. You can make more power at the same RPM just by change the PIPE design and the Porting. You can also increase the RPM to get more power but you have to change the pipe design and porting to get more power. Simply increasing RPM's does make the motor make more power. I'm talking about two strokes.

 

[arteeex]

Higher track speed = higher ground speed.

 

[dirkdiggler]

in other words even at the same horsepower but higher rpms equals higher ground speed

Higher RPM's does equal higher MPH but you have to have the power to pull it. If the motor falls on it's face in a higher RPM range you will actually go slower. Clutch overdrive and gearing plays a roll as well

 

[arteeex]

That is true and Untrue. You can make more power at the same RPM just by change the PIPE design and the Porting. You can also increase the RPM to get more power but you have to change the pipe design and porting to get more power. Simply increasing RPM's does make the motor make more power. I'm talking about two strokes.

I have the sense that you may be confusing power with torque (or work) as it is used in engineering. Power is the RATE that work is done, it is a time function. If you can do more work in a shorter period you will have more power. An engine that can spin up faster under load will record greater horsepower numbers. It's not necessarily about getting higher RPM, it's about getting to higher RPM faster when delivering torque. Changing the flow characteristics through the motor, as you've noted will impact this rate function.

Horsepower is a calculated value that cannot be measured directly. To simplify a bit, it is determined by measuring the torque at two points and dividing that change by the time between measurements. The steeper the torque curve the greater the difference between subsequent torque measurements and therefore the greater the horsepower.

 

[dirkdiggler]

That is true and Untrue. You can make more power at the same RPM just by change the PIPE design and the Porting. You can also increase the RPM to get more power but you have to change the pipe design and porting to get more power. Simply increasing RPM's does make the motor make more power. I'm talking about two strokes.

I have the sense that you may be confusing power with torque (or work) as it is used in engineering. Power is the RATE that work is done, it is a time function. If you can do more work in a shorter period you will have more power. An engine that can spin up faster under load will record greater horsepower numbers. It's not necessarily about getting higher RPM, it's about getting to higher RPM faster when delivering torque. Changing the flow characteristics through the motor, as you've noted will impact this rate function.

Horsepower is a calculated value that cannot be measured directly. To simplify a bit, it is determined by measuring the torque at two points and dividing that change by the time between measurements. The steeper the torque curve the greater the difference between subsequent torque measurements and therefore the greater the horsepower.

HP = Torque x rpm/5250

 

[arteeex]

At a single point. This is a mathematical simplification that describes a linear torque curve, which we know is never the case.

Next.

 

[yamahahaha]

i know the xtx is a bit faster on top and that is because of the approach angle. but i dont understand why because the same amount of track is on the ground...

 

[dirkdiggler]

i know the xtx is a bit faster on top and that is because of the approach angle. but i dont understand why because the same amount of track is on the ground...

It jsut proves that resistance is a greater factor then 'weight or foot print"

 

[stuckless316]

i know the xtx is a bit faster on top and that is because of the approach angle. but i dont understand why because the same amount of track is on the ground...

It jsut proves that resistance is a greater factor then 'weight or foot print"

resistance is a factor of weight and surface area...plus many more things!!!

 

[**sj**]

i know the xtx is a bit faster on top and that is because of the approach angle. but i dont understand why because the same amount of track is on the ground...

think of it as a wheel turning truer...plus big wheel is easier to turn once rolling than small wheel

 

[viento79]

You've got it backwards. Horsepower is a measure of how fast the torque can be applied and does not make anything move. It is the first derivative of the torque curve (really the equation that defines the torque curve). Torque by definition is work. Torque makes things move. To the extent that HP and torque are related, horsepower will determine the acceleration possible and torque will determine the maximum speed.

Very simply, if you had 2 motors with equal HP but one had twice the torque at the same RPM you could expect them to accelerate at the same rate. However the one with greater torque will have a higher top end due to the additional capacity to do work.

Sorry for the correction here but Torque by definition is not work. Torque by definition is a rotational force. Artee, you have your definitions back asswards.

 

[SledFreak]

What was this post about again?

 

[arteeex]

Sorry for the correction here but Torque by definition is not work. Torque by definition is a rotational force. Artee, you have your definitions back asswards.

Nope. Torque = Force X Distance, a cross-product. For torque the force is at a distance d from the center of rotation and this moves thru an angular displacement to do work.

Torque is a moment. When allowed to move, it does work.

 

[**sj**]

or in laymans terms...torque gets the load moving and horsepower keeps it moving

 

[Zakre]

Sorry for the correction here but Torque by definition is not work. Torque by definition is a rotational force. Artee, you have your definitions back asswards.

Nope. Torque = Force X Distance, a cross-product. For torque the force is at a distance d from the center of rotation and this moves thru an angular displacement to do work.

Work = force x distance measured in newtons, gr 11 physics here, torque is much more complicated involing the angle , force and linear momentum (in one plain without friction) or angualar momentum in the real world measured in newton meters.

t = r x f
t = rFsin(θ)

where

τ is the torque vector and τ is the magnitude of the torque,
r is the displacement vector (a vector from the point from which torque is measured to the point where force is applied), and r is the length (or magnitude) of the lever arm vector,
F is the force vector, and F is the magnitude of the force,
× denotes the cross product,
θ is the angle between the force vector and the lever arm vector.

right from wiki http://en.wikipedia.org/wiki/Torque


Its like speed and velocity, they are almost the same but ones a vector aka has a direction and angle.

anyhow hope this clears up the confusion, how about we get back to whatever this thread was about lol