LAPTIME SUM IN EXCEL

Hi . I am trying to calculate in excel the total sum of time(the engine worked etc) expressed in lap time. Any ideas?

Not specifically, it's a very long time since I messed around with excel, and it's a little unclear what you're asking?

Is it the amount of time, as a percentage, of applied power over the lap?

If you want to log the engine running time, including practice, idle, etc, you can use a simple 12V hour meter, or timer, connected to the ignition feed; use a manual switch for total race (and practice, if required); if you just want the total over xxx rpm, you may be able to use an ECU output triggered for that; a manifold pressure switch for under boost; a pedal contact switch for any throttle application; etc.