[Vwdiesel] Tacho Find

[Val Christian]

How about using knowns?  Like transmission ratio and tire size?
If you don't trust your speedometer, then take a GPS with you
and do a couple of straight runs.  You should be able to repeat
within 1% or worst case 2% accuracy.

Val


> 
> A few days ago I was down my local Car breakers and I
> spotted a diesel tacho in a lorry. Couldn't leave it so I
> had it :o)
> It looks like a motor cycle rev counter in size about 3"
> across.  The scale 'max's out at 3500 rpm. It must have been
> attached to the alternator 'W' connector but as the alt. was
> gone I couldn't see the pulley ratio ( although this
> wouldn't tell me the No. of poles...) The three wires
> (excluding the light) were black/yellow streak, red /orange
> streak and brown. Definitely not British Standard colours!
> It turns out it works on my alt with the black one being
> batt+ red being signal and brown earth(-ve)
> I thought to myself how can I check the calibration without
> another  diesel tacho?
> Well I reckon that if I was to use a gas strobe on a gas car
> parked alongside my 'Q' and used it to strobe the diesel fly
> wheel at different speeds of the gasser (noted with its
> gasser tacho) and then adjust the speed of the diesel to
> match that'll do it (clever eh :o)
> 
> Alternatively I'll just throw this back into the sea and
> convert one of my oem gasser tachos...
> _________________
> Mark-The-Miser-UK
> 
> "There's nothing like driving past a bonfire and then
> realising; its your car on fire"
> 
> Be like me: drive a Quantum TD
> 
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