Horsepower

hi, i hope i am in the right section, i wanted to ask, is there any way to figure out how many horsepower a coupe has approximately, without using the dyno?

I believe you can get a couple of apps on the phone that can give an approx measure of power based on used your GPS

......... or ask a friendly police man to measure your speed/time

thanks, i will try Begbie's advice.