alfas
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| posted on 10/7/14 at 10:05 PM |
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speedo signal for Vapor Trial Tech digital speedo
the former owner used the original sensor in combination with the original (single) magnet on the proshaft.
once the car reached around 30miles (in 4th gear) the speedo started messing-up, the faster you got the less it showed. the former owner never cared
about that.
first i thought the gap between sensor and magnet was wrong....it wasnt.
finally i put the sensor near one of the wheels and the magnet was clued to the rim....and it worked!!!
does that mean that such (motorbike, ATV) speedo“s do only cope with a lower frequency of signals (like fitted to a wheel) but using them at the
propshaft they will fail?
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alfas
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| posted on 10/7/14 at 10:16 PM |
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i think i found the answer myselves...in the US locost forum:
"Speedo sensor is mounted off the tail of the trans and the magnet is on the ujoint."
but finally:
"I ended putting the speedo sending unit on a rear hub. I had it on the driveshaft, but it turns out that the sender cant deal with more than
40Hz."
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owelly
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| posted on 10/7/14 at 11:26 PM |
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My Vapor Trail Tech speedo does the same. I have the magnet on the diff flange and once above walking pace, it goes screwy. I managed 245mph at Santa
Pod......
http://www.ppcmag.co.uk
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snowy2
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| posted on 12/7/14 at 06:53 AM |
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Mine on my car was bolted to the caliper mounting brackets and the magnet to the rear of the brake disc. The original sensor sometimes gave problems
like yours but after only 1000 miles or so packed in altogether when I tried to buy another one it was some outrageous price of about £30 so I
dismantled it. They are just micro glass encapsulated reed switches they cost 20p or less from some suppliers (maplins) I found they work best
"end"on so I soldered one to the sensor wires and silicone filler glued it into the mounting tube it then worked very reliably for some
20000+ miles and at speeds well above legal in this country when we toured the continent.
sometimes you are the pigeon, most of the time the statue.
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snowy2
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| posted on 12/7/14 at 07:02 AM |
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The closer the sensor can be to the magnet the better it works. The original sensor had a small gap before the end of its mounting tube when I remade
it there was none. That alone might be enough to improve reliability.
sometimes you are the pigeon, most of the time the statue.
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alfas
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| posted on 12/7/14 at 09:23 AM |
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at the probshaft it didnt matter if the sensor was mounted with zero gap or with a few millimetres...when the prop reached a certain speed the sensor
couldnt cope with it
now mounted on the wheel it works perfect even with a huge gap of several millimetres.
its definately not desinged to pick-up high frequencies, as created when mounted at propshaft.
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