Acceleration diagram tutorial

Acceleration diagram tutorial

Description

The acceleration diagram shows the acceleration of the motorcycle  in all the gears. On the Y-axis the acceleration is given (in m/s^2), And on the X-axis the speed is given in km/h. Every line represents the acceleration in a gear. The topmost is the first gear, the lowest line represents the highest gear. Note the acceleration is limited to 9.8 m/s^2 (1g), visible in the first gear.

sample of an acceleration diagram

Topspeed

The topspeed is where the acceleration line crosses the 0.0 acceleration (m/s^2) line. Note that the acceleration continues beyond that, but the acceleration becomes negative.
 

Topspeed sample

 

Shifting points

The shifting points are where the line from the previous gear crosses, or is closest to, that of the next gear. Hovering over these points will reveal the rpm at that point.

Shifting points

 Acceleration diagram sample

To use the accelartion diagram, you can change any of the parameters in the form, then press the 'acceleration' button. In this case, we changed just the riders weight.

Result of change to rider weight

We can see the lighter driver clearly has an advantage, but suppose the more solid driver doesn't like this, and wants to know what is required to be on par again. First, he decides to increase the size of the rear sprocket to 49T, because he's not concerned with topspeed, just accelleration and a shorter gearing gives a faster acceleration, right? Wrong. The acceleration has increased at lower speeds throughout the gears, but the rider also has to shift earlier (this becomes more evident in the lead and 1/4 mile diagram, but then you cannot see what caused it). There is a difference in acceleration, but not as much as you might expect.  The way to go is add more power, or loose weight. For the sake of the story, the rider decides not to loose weight, so the performance must increase. He can just change the power and torque parameters untill the difference is solved. Adding 2.5 hp and 3.3 nm solves the problem. K&N filtrage and rejetting/remapping might solve the problem.