Has anyone worked out the Mph per 1000 Rpm figures for an auto Z32 TT? Through the gears, I have the figures for the manual, as published in Autocar in May 1990.

 

My speedo is reading about 12% low! and I need to check against the revs.

 

If anyone has I'd love to know.

The Z-speedo is not the most accurate speedo around..especially if it has been converted from kmh to mph (or vice versa)

I've seen speedo's with deviations of over 15%

 

You'll need an Apexi multichecker, AVCR , Techtom ...or even better a GPS to accurately measure the exact speed

 

-Eric

 

[This message has been edited by lymon (edited 20-07-2001).]

I used my GPS to verify the speedo accuracy and it's not bad. At an indicated 70mph it's actually 66 and at 40 it's actually doing 37. This is a jap speedo that's been converted. I reckon it was just about spot on before I put UK spec wheels/tyres on the back.

I'm all for fancy gadgets in my cars, so does anyone know of a nice looking GPS speedo? The only one I've found so far is the Techtom one, which is a bit 'klunky' looking, next to an Apexi AVC-R say..

 

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Az

Racelogic do a very nice which can download afterwards to a PC.

 

leigh.

 

 

Isn't that the one that costs about the same as the car ??

Thanks everyone,

 

I have mathematically calculated the mph per 1000 rpm.

 

FYI it equates to 27.82 mph per 1000rpm.

 

This is on an z32, 1990, Auto with 225/50/16 boots all round.

 

That means it was nudging 145 last night!!!

Hi,

Don't forget that at speed the rolling circumference of your tyres becomes greater, due to heat and pressure increase.This effects the accuracy of your speedo, also!

The gearing on my NA was quite low...approx 21.5mph per thousand revs.This equated to 150mph at the red line in top gear.(Or it would have done if the Cops hadn't stopped me at approx 140mph!)

JEZ

That's why your handy pocket GPS is good for checking the speedo. You can get a Garmin eTrex for £99. Others may be cheaper.