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Vapor issue
jeffw - 19/6/08 at 05:34 AM

I took the Phoenix out prior to it's MoT last night. This is the Vapors first run at any speed since fitting.

Basically below 20mph it's fine but above that it reads 0.

I've put 2 magnets halfway down the propshaft and mounted the sensor off the side panel. I've had to open up the gap between the sensor and the magnets as they kept hitting each other when the propshaft/engine/gearbox moves under acceleration/braking etc.

I think the gap is the the problem...How has everyone else mounted their sensors ?


worX - 19/6/08 at 05:52 AM

Not had same problem, but it would stand to reason that if one of the parts is moving then you're going to have to mount the second part to it also.

You will have to move the magnets to the front/rear of the prop and then mount the sensor on the gearbox/diff or something like that?

Steve


jeffw - 19/6/08 at 06:31 AM

Yeap..I think that your right and I'll have to move the magnets. I didn't realise that the propshaft moved as much as it does !


lotusmadandy - 19/6/08 at 07:29 AM

I had the same bother with my vapour speedo.
the problem is that the prop spins to fast and beyond 20-30 mph the computer does its own thing.
i cured mine by fitting the sensor to the rear hub and using one of the bols with a magnet in the head.
i drilled and tapped to m6 in the rear drive flange and thead glued the bolt in.
my speedo now works perfectly.
Andy


jeffw - 19/6/08 at 01:34 PM

has anyone got the propshaft method to work ???


jeffw - 19/6/08 at 07:45 PM

Andy, have you an photos of how you did it ?

[Edited on 19/6/08 by jeffw]


jeffw - 19/6/08 at 07:47 PM

In an effort to answer my own question I've moved the sensor to right behind the gearbox at the front of the propshaft.

I've cut down on the number of magnets to one....it now doesn't hit the magnet and is within 2mm of it.

The speedo is spot on according to the GPS (1850mm wheel circumference / 3.9 diff ratio) all the way up to 33 MPH after which it gives complete nonesense.

So I reckon these units are good for 128.7 MPH if you mount it on the wheel and a lot less on the propshaft.

The spec says they will read upto 400MPH although I think this is the LED not the electronics.


DutchBoy - 19/6/08 at 08:01 PM

its because the pulses are so fast that it keeps reading an magnet...

how big are your magnets..??

try to make them smaller..

also less magnets will do better..


jeffw - 19/6/08 at 09:10 PM

It's now 1 rare earth magnet approx 3mm across. Umm...I wonder if the issue is the rare earth magnet is too strong !


jeffw - 20/6/08 at 08:57 PM

Changed for a normal magnet and no difference...

I'm trying to figure a way of fitting the sensor to the front suspension arm with the magnet on the wheel.


les - 25/6/08 at 07:02 PM

Jeff,

Hi- I have sent a u2u,

I have mounted the sensors on the propshaft, for an acewell speedo so similar- I put the whole setup on the differential end- its mounted solidly to the chassis rather than on rubber mountings like the gearbox / engine and so doesnt move- i drilled and tapped a thread into the flange then screwed in the magnet- works well.

les


jeffw - 27/6/08 at 03:59 AM

Thanks Les. The Vapor doesn't like the propshaft. I've mounted it on the front wheel and it works to a point.....the displayed speed comes and goes because the magnet/sensor spacing varies too much with the wheel turning and the suspension.

When I get back from the Ring I'll mount it on the rear axle which should be much better.