10,000 rpm porsche tachometer, can anyone help?

[66S]

I tested my 60,000 Imp tach and it is for a 6 cylinder, high pulse voltage early type. No date, no part nr., post mounts.

[304065]

The "Imp" does not have anything to do with redline. There are SWB tachs with an 8,000 rpm redline that say 14000Imp. There are 78 tachs that say 21000 Imp with same redline. I think it's "Impedance" which is a reference to the tach driver circuit.

[914-6gt]

Electrical Impulses...


Repost.
This information comes from a couple of well informed and knowledable sources I have relied on over the years, Hollywood Speedometer (http://www.nhspeedometer.com/) being one of them.

10K VDO Tachometer
30,000 impulses / 60 cyles = 500 impulses
at 50 hertz per thousand (50 x 10 = 500)

8K VDO Tachometer
24000 impulses / 60 cyles = 400 impulses
at 50 hertz per thousand (50 x 8 = 400)

* Maximum deflection relates to the ability of the instrument to accurately read the 'rpm range' it was designed for---the reason why an 8K tachometer could never be an original 10,000 rpm VDO gauge unless it was in fact 'modified' to do so.

[914-6gt]

60K/6=10K, maybe not relevant but interesting. I dropped out of Electrical Engineering.

Information given to me came from the guys that service these gauges, if there is a frequency conversion in the circuit of the gauge, that's news to me. In the meantime, I will confirm.. In Europe they use 50Hz.