[Signman]

Will throw my .02 in.

During that time there was a showdown at a big money race at Atco.
People were watching in the stands and the culprit was not looking at his opponent at all just staring at the tach going through and going dead on.. When the crowd gathered and officials asked for an inspection the car and driver loaded up and left.

The explanation was that the tach was not a tach at all but an indicator. If when approaching the finish line if it read a predetermined set RPM you would be going dead on. Lower you were slow & higher you were fast.

In this scenario there was no throttle or nitrous controller. The driver controlled slowing down & speeding up.

The Matty Box I believe is still for sale.
It used a wheel counter on a front wheel. The pickup was the tell tale. But why can't you use drive shaft RPM?? Make your wheel stander dead hook and it will work fine.

That's why external inputs other than engine sensors are not allowed to be connected to EFI ECU with internal data logging. Brings this issue on board as well as traction control.