E6K always reads a little lower. Gets off by more as the RPM's rise ( of course.. ).



If my tach says 7k, am I really spinning at 7k? Or is it more like 6400 or something that the Haltech says?

 

I would believe the haltech over the analog gauge.

 

This is normal. Mine is off too. The haltech is more accurate than mazda.

 

the reason is for the electromechanicals of the tachometer. The movement of the analog gauge itself has a certain degree of hysteresis (usually around 5%). The Haltec is displaying a digital numeric output of the crank angle sensor. It is definetly more accurate.

 

the tach in the car is driven by the ignition, and its got a needle with mass to move, and its 15 years old.



the e6k gets its number from the cas, which is also 15 years old.



mike

 

the cas is also gear driven, which has some slop.