engine failures would be good, make you think about your change up and down points
trouble is it would have to be consistent not like that in grandprix where it always felt a bit of a random number generator type formula, also not instant if you overrev but more of a cumlative effect of high revs, throttle, load on engine ( remember revs on the bbc by crammond, f3 engines, give them full throttle at low revs and kaboom) engine temp etc.