GT40s.com - View Single Post - Question on msd 6-al ignition tach output

dave harris · 11-24-07, 05:23 PM

The msd booklet states that the tach output is a 12 volt 20% duty cycle signal - but they don't state how many pulses per revolution - i've assumed it meant 1 pulse per rev, but my VDO tach seems to think that it's looking at a 4 cylinder (reads 2x rpm based on timing light). (it is quite possible that i've mis-configured the VDO tach, but before I tear the dash off, I would like to have some more information).

Does anyone know the pulse rate on this output?

Thanks

Dave

11-24-07, 05:23 PM	#1 (permalink)
dave harris daveharris 3 Tenths Join Date: Jun 2002 Location: Rohnert Park ca GT40: Northern Ca, Posts: 354 Rep Power: 10	Question on msd 6-al ignition tach output The msd booklet states that the tach output is a 12 volt 20% duty cycle signal - but they don't state how many pulses per revolution - i've assumed it meant 1 pulse per rev, but my VDO tach seems to think that it's looking at a 4 cylinder (reads 2x rpm based on timing light). (it is quite possible that i've mis-configured the VDO tach, but before I tear the dash off, I would like to have some more information). Does anyone know the pulse rate on this output? Thanks Dave __________________ Dave Harris DRB GT-40 Chassis # 41