Didn't ford use a data logger around Le Mans which recorded revs, throttle, brakes and gearchanges which they then used for engine run simulations for a full 24 hours? in the mid 60's this was considered witchcraft!! Its the same one that Christian Bale ripped out in the film, although I knew I couldn't watch the film in the cinema as I was shouting at the screen in the first few seconds of the trailer as I saw an anodised gearbox pump on the rear of the box....and it didn't stop there.... I think I have a few articles on the engine simulator and will look through them to see if there is any reference to a lap counter.