RPM relation to MPH

[oliverkelly]

Unfortunately, on the way to Elvington my Speedo stopped working. Probably worst possible time for this to happen. I suppose I could always claim that I maxed it

However in an aim to judge speed attained in the morning I need to know if there is a direct relationship between RPM and MPH in a particular gear.

For example if you are doing 50 mph and 2000 rpm, does it follow that you would be doing 100 mph at 4000 rpm, and 150 mph at 6000 rpm.

I know I got the car up to 6500 rpm in fifth in the morning but don't know what speed this equates to. I seem to remember that at 3000 rpm I am going at 80 mph.

Someone paced me in the afternoon and they said that I was doing 170 at about 5500 rpm.

Also any idea what could be wrong with the speedo and mileometer ?

[GreenV8S]

quote:For example if you are doing 50 mph and 2000 rpm, does it follow that you would be doing 100 mph at 4000 rpm, and 150 mph at 6000 rpm.

Yes.

[pennoir]

I had a similar issue in my Tuscan on Saturday, (along with several other people) - no Speedo! My S6 engine with standard gearbox gives 27.5mph per 1000rpm in 5th. I managed to squeeze 6700 rpm on one run up the straight (towards the right hand corner as you faced the track from the pits) I think this was down wind and my engine seemed to be missfiring above this so could not squeeze any more out of it. Anyway should be about 185mph....