vmax

I know that the speedo in car has a margin of error, but by how much. Is a GPS speedo my accurate... If so where can I get one.

The reason why I ask is because the speedo on my MY01 indicates a certain speed but becuase the car is so much more quieter than my previous scoobs, I get this nagging feeling that the speedo is out by quite a large margin. This is the because the car does not seem to behave as though it is at the speed indicated.

Its not a problem... It's just kinda weird.

How can I test the accuracy

Big Col

Isn't it better to use the revcounter because they are more accurate?

Autocar and other magazines have the mph1000rpm gearbox data listed in their road test data.

For example my car (Corsa GSi .... ahem ) is geared 19.7mph1000rpm in fifth gear. Therefore at a true 70mph you are doing 3553 rpm.

Anyone else agree ??

Of course if you fit big wheels this screws this theory up.

tokyo_steve

I haven't tried at high speeds yet, but up to 80MPH the JAPANESE speedo in my 01 is spot on. Tested with my GPS.

May be different in over there, but I'd think they'd use the same sender & electronics but change the digits painted on the guage.

Steve

Neil Smalley

I ran such a test in jan this year

Paul Wilson

hand held GPS can be got from about £100, they are not very accurate for instant readings as they have an update time of a few seconds. Camping shops and chandlers sell them, as well as various mail order places

Have you gone form a Jap import, to a UK or vice versa? as Jap imports often have a redustion box to give readings in mph rather than kmh. This can be another source of error, or correct errors ion the speedo.

IWatkins

vmax,

If you can get to a rolling road, most can do a speedo chart for you. e.g.

20mph on speedo = xxmph for real
30mph on speedo = xxmph for real
...
...
130mph on speedo = xxmph for real.

Handy to know exactly what 70mph is on your speedo

Cheers

Ian