I failed to completely twist down the yellow engine oil fill cap after a top-off, and drove a significant distance. What type of damage may that have caused to the engine?

 

IMO none
zero
zip
nad-da

You would only have to worry if dirt or debris dropped down the oil fill tube. This would only likely happen if the cap was left off.

 

i drove an entire track day without a dip stick. you'll be fine. why are you worried? seriously.

 

did you get a cel? nothing really, if u did just reset the ecu and avoid unneccessary trip to the dealership

 

Like everyone else has said...................."nothing", you just probably should check the level again just to be sure no oil was lost, but if you had.....you'd probably have seen white smoke by now, so just check the level to be sure.