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pulses per mile
bracey - 26/3/07 at 04:29 PM

can some genius work this out for me please before my brain melts
trying to work out the number to put in my speedo
have got so far
8 pulses per 100cm
14 pulses per tyre rev
195/50/15
thank you in advance
richard

02GF74 - 26/3/07 at 04:43 PM

quote:
Originally posted by bracey
can some genius work this out for me please before my brain melts
trying to work out the number to put in my speedo
have got so far
8 pulses per 100cm
14 pulses per tyre rev
195/50/15
thank you in advance
richard


* wheel diameter is 576 mm (as per tyre spec, in reality it will be different)

* wheel circumference is 1.810 m

1 mile = 1,600 m

so no. revs per mile is 884.

14 pulses per rev gives 12,376 = a lot

mad4x4 - 26/3/07 at 04:45 PM

Why not set it to pulse and then drive a mile?

bracey - 26/3/07 at 04:53 PM

if i set it at 6500 it reads nearly double and can do 130 mph in second gear

turbodisplay - 26/3/07 at 04:59 PM

I would say that you should have more than 1 tyre rotation as 14 pulses + - 1 pulse is an error of 7%.

Any other errors in calculation can easily take you over 10% error.

100 pulses would be better ie 1 %.

bracey - 26/3/07 at 05:05 PM

as the instructions say i put 4 mags in prop ,would it be worth drilling two out???

turbodisplay - 26/3/07 at 05:48 PM

I might have been unclear, if you count let say 5 tyre rotations , then divide pulses by 5 it will give you a more accurate result, ie 14.75.

Thanks
Darren

RazMan - 26/3/07 at 08:55 PM

Using the theoretical circumference is not accurate and the only way to do it is to mark the tyre and ground, roll the car forward for about five turns of the wheel and mark the ground again. Measure the distance between the marks and divide by five - voila.

02GF74 - 28/3/07 at 11:20 AM

quote:
Originally posted by bracey
as the instructions say i put 4 mags in prop ,would it be worth drilling two out???


so now you are giving totally different information to what was in the first post and to what I used to do the thinking for you.

provide proper info, then you may get valid answer instead of wasting my time like that

working form the prop, now we have no. magnets, all that is now needed is diff ratio and the rest can be worked out.

bracey - 29/3/07 at 06:41 PM

standard sierra diff ?3:91 i think