To help pass the winter blues I've taken on trying to get my second VDO tachometer to read properly. The issue with the disappearing LCD hour meter has been discussed at length on this site but in addition to that issue, my tachometer has never read properly as compared to my strobe tach ( sometimes high and sometimes low by more than 200 RPM).
In reviewing thenVDO setup instructions, one must input the number of pulses into the tachometer so the tach knows how many pulses per revolution.
I also believe that I need to take into account the different size pulley diameters on the crankshaft and the alternator. In my case the crankshaft diameter is 4.625 inches and the alternator pulley is 3.1875 inches. The ratio crankshaft to pulley is 1.45.
My balmar alternator model 70-110 has 12 poles. I believe I need to set the tachometer at 12. X 1.45 or 17.45 pulses per engine RPM.
Im pretty sure this is correct and I recall we discussed it back in 2009 but just wanted to see if someone could validate for me.
Thanks
Marc
In reviewing thenVDO setup instructions, one must input the number of pulses into the tachometer so the tach knows how many pulses per revolution.
I also believe that I need to take into account the different size pulley diameters on the crankshaft and the alternator. In my case the crankshaft diameter is 4.625 inches and the alternator pulley is 3.1875 inches. The ratio crankshaft to pulley is 1.45.
My balmar alternator model 70-110 has 12 poles. I believe I need to set the tachometer at 12. X 1.45 or 17.45 pulses per engine RPM.
Im pretty sure this is correct and I recall we discussed it back in 2009 but just wanted to see if someone could validate for me.
Thanks
Marc
