Speedo Calibration

[greenmac80]

as above who in adelaide does speedo calibrations?

i have an aftermarket spec speedo and an electronic speed sender from a newer toyota that fits into the t50 i have,

need to calibrate it.. however if i can figure out how many revs per km the car does i can do it myself as the sender is 4 pulses per rev.

but i'm a maths dumb ass.

 

thanks, Luc

[jono1986]

I've heard guage works could help you with that, or you could get a speedo corrector from jaycar for about 55 bucks, just needs assembly

[greenmac80]

nevermind i figured it out.

 

my tyre spins 551 times per km the diff ratio is 4.11 and the sensor pulses 4 times per rev

 

so 551x4.11x4 = 9058.44 pulses per km. sweet as bru.

[ke30 driver]

to check how accurate it is. use a gps as they tell u how fast you are going and most gps's are more accurate than new car speedos

[Raven]

to check how accurate it is. use a gps as they tell u how fast you are going and most gps's are more accurate than new car speedos

 

A GPS also only updates once per second, so its more a guide as its not THAT accurate. :)

[altezzaclub]

Somewhere around must be a measured Km or two on a motorway or major road. They have odo-checking markers for the public and often road engineer's markers on bridges and posts.

 

Just run along that at a constant speed with a stopwatch, its what we did before every set-speed rally. High-school physics... spd=dist/time.

 

Time for a km in seconds =3600/speed

 

So its

 

30seconds for a km at 120kph

 

36seconds for a km at 100kph

 

40seconds for a km at 90kph

 

etc

[Bamboo]

how I've done it. Mark out 1 km exactly. yeah thats the tricky bit. Set the trip meter to 0. Drive the 1km. See what the trip meter reads. Use the + - percentage to work out the inaccuracy. I know analogue gauges can be tricky, but a very good indicator.