Just sound it out. You can tell when the engine is getting near its limit because it goes like "WWWWAAAAAAAAAAAAAAHHHHHHH"

__________________
1982 240D.
My name is Michael, and I am an 18 year old binge-drinkin', cigar-smokin', novel-writin', all around unsavory and unnattractive guy. I tell long-winded stories, and I only shave once a week, although I've had to do it every day since I was 16.