LapSim: Professional racing simulation software



LapSim wants to provide a fast, comprehensive and easy to use simulation package for your racing activities, anything from a professional racing outfit running a full aero racecar to an amateur preparing and driving his own car.

LapSim figure showing 3D model of a vehicle with the brake system highlighted

The software used for all the licenses is the same and available in the free download.

A free version has been available from 2004 onwards, due to which no other race simulation package is so extensively tested and used as LapSim for the widest variety of vehicles.

From our perspective simulation is always a simplification of a complex reality. Simplification does certainly not mean useless, it all depends what is the goal to analyse. Most important is to be aware of the simplifications of the model and if these simplifications might have an effect on the conclusions one draws out of the behaviour of the simulation.

LapSim figure showing 3D aeromap

One should see the free version as a clear exponent of this thought. Although very limited in the amount of parameters one can edit to describe the vehicle, one should still be able to get the simulation close to the behaviour of the real vehicle, proving the statement that a 'simple' model can still generate a relative good correlation.

We believe in our approach and are confident that if you invest your time and are looking for simulation software, LapSim will convince you. If you subsequently purchase a license you will know exactly what you are getting.

Make something complex, feel easy
Extensively tested in DTM and LMP1
As accurate as simulation can be

LapSim is completely developed by Chris van Rutten, both the calculation models as well as the Graphical User Interface (GUI).

LapSim figure showing tire characteristic of lateral force versus slip angle for several vertical loads

In 1995 Chris graduated with a master’s degree in Mechanical Engineering from Delft University, section Vehicle Dynamics, lead by Professor Hans Pacejka.

His final research project was performed at Toyota Motorsport in Cologne, where he analysed the influence of non-linearities in the suspension setup, their effects and how to optimize them.

LapSim figure showing 5 compression and rebound shockabsorber characteristics

After the project was finished, he started his own consultancy business.

By the end of 1996 Bosch Motorsport granted him the assignment to develop a simulation package for them, LapSim.


First release of LapSim


Integration of a mono-spring and third spring configuration in the simulation model.


LapSim basic becomes a free download. Average 10.000 downloads per year.


Development of the automated setup optimisation routine, with a subsequent setup variation routine around the "fastest" setup to see whether this setup is a local minimum.


Start of the development of an engine simulation in LapSim. This part has been done out of personal interest. We wanted to create a simple tool, in addition to the lap simulation which would enable the customer to judge whether a certain engine/chassis combination would be competitive in a certain class.

Complete calibration of MS4 Sport system on a street Porsche 964.


Development of an 7 poster dynamic model in LapSim. The mathematical model of LapSim is capable of doing a lot more than driving over the flat surface as used in the lap simulation. The dynamic model creates a possibility to analyse and tune shockabsorber characteristics in the simulation model.


Complete calibration of MS4 Sport on 944 Turbo street legal race car.


Calibration of the LMP1 TC was integrated in the GUI of LapSim. Enabling faster adaption to different tracks and circumstances.

Engine: Development of a custom made camshaft for a Porsche 944 Turbo engine, using the engine simulation, significantly improving the engine characteristic.


The GUI of LapSim was used to analyse and model the functioning of the Variable Turbo Geometry of the LMP1 car, leading to a completely new control strategy for the VTG.


Integration of a hybrid system into LapSim. The model was used to determine which key factor had the main influence on laptime. It was used to compare the different concept options.

Engine: Complete calibration of a MS4 Sport ECU on a Porsche 968 engine with variable camshaft timing. The variable camshaft timing gave interesting insight for the engine simulation.


Engine: Development of a custom made camshaft for the Porsche 964 using the engine simulation. Camshaft was produced, mounted and tested. Adaption of injection timing correlated with the predicted increased fill rate. Acceleration runs showed the predicted significant increase in torque, power band and max power.


Chassis: LapSim calculates the driving line out of each on-car recorded lap which is loaded in LapSim, the new functionality opens the possibility to compare these laps more closely.

Engine: Testing of purpose build exhaust with significantly longer primary length headers. Change of engine characteristic in good correlation with the engine simulation.


Chassis: introduction of 4D Aero map with a wing angle variable. This enabled me to work in the DTM with one aeromap for all wing angles.

Engine: Testing of a variable length intake manifold, which lead to a revised intake simulation.


Restructuring the setup variation runs, enabling more runs in one time, giving better insight on laptime influence of the main setup variables in preparation for a race weekend.


Combined slip calculation of the tire model has been revised. Especially in mid corner, the correlation of longitudinal slip could still be improved.

Restructuring of the data processing in the background of LapSim. Due to extensive work in the DTM, a new release was not finalized for too long.


Option to directly load AIM *.xrk data files into LapSim. Due to the availability of GPS in the AIM data, GPS data is used to calculate the driving line. This enables much better driving line comparison within LapSim.