Drive Van's tach from E/P Mag?

Steve Brown · #1 05-21-2009, 06:37 AM

I'd like to get rid of the transducer and drive cable and run my Van's tach directly off of the tach signals from one of my E/P mags. I checked the installation instructions for the tach and there is nothing there about the nature of the required signal.

Anyone done this or know anything about it?

RV7AV8R · #2 05-21-2009, 08:39 AM

You can not hurt anything if you connect the Tach drive from the p-mag to the tach and try it. The new p-mags have 5 volt or 12 volt pulses coming out of them (I think it is programable somehow). My Vans tach worked off either the Slick or the p-mag (I had a switch to feed either one). I eventually replaced the Vans Tach because it read 200 rpm high and installed an EI tach which I love. I should add that the Vans Tach I had took its input from the Slick p-lead.

N520TX · #3 05-21-2009, 08:49 AM

I've tried this in the past for the same reason - to get rid of the tach drive. I never managed to get it working. I changed the parameters (# pulses per rev, voltage of pulse) to encompass all combinations but could not get the vans tach drive to read correctly - if I recall, it was (at most) reading around 70% or so of what I know to have been the real tach RPM.

Here's a semi-recent thread where I was fishing for that information without any luck:
http://www.vansairforce.com/communit...ad.php?t=36841

If you find the combination that works, please do share.