The Vehicle Speed Sensor (VSS) tells the ECU how fast the car is moving. In most hondas, it pulses to ground 4 times per revolution of the axles. Most OBD0 cars have the electronic VSS module inside the speedometer in the cluster, which is cable driven. Most OBD1 and OBD2 cars have an electronic VSS mounted on the transmission, and an electronically controlled speedometer in the cluster. One function the VSS appears to play in stock ECUs is to enable a Speed Limiter. The VSS is also used to output a signal to the gauge cluster. A third function is to calculate gear dependent fuel corrections. Lastley, the ECU uses the VSS for cruise control. Launch Control code also uses the VSS.

In most cases, the Speed Limiter can be disabled in the ROM, but in the cases where it cannot be removed in code, other tricks can be done. If you wanted to build an electronic device to remove the speed limiter without touching the internals of your ECU or the code running it, you would need to limit the frequency of the pulses generated by the VSS module to less than the frequency of your VSS at the Speed Limiter.

What I would do: (says Dave Blundell?) -Get a multimeter with a frequency counter or a oscilloscope -hook it up to the VSS signal being fed to your ECU. -go for a drive. Record the frequency of the speedo at 100mph (safely below your speed limiter) -build a device to limit the frequency to the 100mph freq maximum. -it would be good to pass the actual VSS pulse through unaltered at lower speeds.