non-DFI tach question

Alex C. Peper xxalexx at ix.netcom.com
Tue Nov 2 13:11:29 GMT 1999


Dynos use a tach generator.  You could hook a small 
surplus one to shaft and read voltage.  Also dynos use
a shaft counter you can make one with a magnet and hall effect
sensor from digi-key.
Alex
> Date: Mon, 1 Nov 1999 22:40:56 -0500
> From: brucep at ptd.net
> Subject: non-DFI tach question
> 
> I've searched high and low and haven't been able to find any info that was
> of any use on this subject so I am turning to the "minds" of this group.
> 
> I am building a steady state dyno and need to add a tach to it. I want to
> measure the shaft speed of the dyno. (I don't want to read the engine
> ignition) I can't afford a digital tach setup so I am looking to use a
> analog 4 cylinder tach I have laying around till I can afford to upgrade.
> What would be the easiest way to make this work? Does the tach sense the
> drop of the ground when the points open. Could I use parts from a GM 4
> cylinder HEI coil ie: coil pickup and ignition module. I think I am headed
> in the right direction just need some advice on different ways I could do
> this. Ideally I would like to have a digital display which would allow me to
> have a more realistic reading of rpm's as opposed to well it looks like it
> is 2000 not 2010, 2020 or 2050. Any help would be greatly appreciated. And
> sorry for taking up bandwidth for the non-dfi post but this was my last
> place to ask . . . thanks in advance.
> 
> Bruce



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