25% More Speed Reading On Speedo And Pfc Only Reads Up To 173 Kmz

[Andrew.Y]

Hi All,

It's an R34 99 non-Vspec GTR. The car had:

* Gearbox reconditioned.

* Rear diff reconditioned. Ratio unchanged.

* Nismo Dash

* 265/35/18 RE001 Tires

Funny enough there is a 20%-25% discrepancy between on-car GPS speed and the Nismo Dash speedo. Yes, the speedo reads 20~25% higher than the actual speed. Four wheel sensor light is off.

Also, Power FC reads only up to 173 kmz.

What is causing all these?

Thanks.