370z speedometer vs computer trip avr. speed
 

while driving at constant speed and reseting the speed average on the comp. trip, it calculates different speed reading!!

speed average should be the same as the current speed if it were constant , but it reads lower by about 6% !!

i know the speedometer is not that accurate, but since its the same car it should read from the same speed sensor. does our car have more than one speed sensor ??

if you lost with what im trying to say please see the video below



by the way, the same thing happens with my 350z i previously owned.

and measuring the speed using mobile GPS readings gives the same results on the computer trip avr. speed

can someone explain !!

Stock speedometers are designed to read high; in my experience, most stock speedos read 2-3 mph higher than the realtime GPS speed or roughly 3-5 kph. I can't help you on the sensors but this should be an interesting question to answer!

Assuming that the computer is calculating the average by taking a series of vehicle speed readings, it could be plotting the first reading at 0 KPH.

It you have 1 reading at 0 KPH and 17 reading at 100 KPH, then the average speed is 94.4

If this theory is correct, you would expect this to even out over a longer period of driving.

This is just a guess.

good point

i'll try to stay on constant speed for longer time, if the average speed reading approches 100, then your theory is correct