Relevance more for street legal cars than pure race cars.

Figure showing the gearbox menu with the option to select the straight line acceleration

In the gearbox menu, you can select a straight line acceleration option. A new menu opens in which you can specify the starting conditions as well as the end conditions of a straight line acceleration.

By pressing the "Start straight line Simulation" button the simulation will be calculated.

Printscreen of the LapSim GUI with the results of a straight line acceleration simulation

In the plot you will see the resulting acceleration graph, with times to dedicated speeds and distances highlighted.

Should the tire grip be the limiting factor, the speed trace becomes orange.

You can click in the figure to get extra information at the selected point. Selecting a point at the rpm trace, will select a rpm point at the nearest 100 [rpm] mark.

Standing start

Printscreen of the LapSim GUI showing the start options of the straight line acceleration

For a standing start, select 0 [km/h] as the starting speed. LapSim will select first gear and the engine rpm at which the maximum torque occurs. Both can subsequently be altered.

LapSim will simulate a sliding clutch maintaining the engine start rpm, till the vehicle has reached the speed which corresponds to this engine rpm.

Printscreen of the LapSim GUI showing the rolling start options of the straight line acceleration

Rolling start

Select the speed with which the simulation should start. LapSim will select the appropriate gear and subsequently corresponding engine rpm with no clutch slip.

Changing the start gear, will cause LapSim to adjust the start rpm.

Alternatively, you can change the start rpm. If the specified start speed is not 0, LapSim will select the corresponding vehicle speed, taken the selected gear into account.

When to stop

Printscreen of the LapSim GUI showing the stop options of the straight line acceleration

You have to define when the simulation should stops.

There is a speed limit, a maximum gear or a maximum time. The simulation stops when either of them is reached.

As an option you can put a maximum speed, instead of the highest gear.

Estimating a power curve out of on-car data

Printscreen of the LapSim GUI showing the option of a single gear acceleration with results

If you let the software do a rolling start acceleration in a certain gear, you can select the same gear as the limit. This will cause the simulation to stop at the shift point.

If this occurs, LapSim will present the results slightly different. You will see the times it takes to reach certain rpm.