Electronic Speedometer

Stig,

What sender are you using?

I had a similar problem with my set up (Stewart Warner) using originally a Hall Effect sender in the gearbox and subsequently a proximity detector against a bolt head on the drive shaft...

Both of these seemed to produce a decent shape output when tested with an oscilloscope, but eventually I found the problem was that the output, while a nice shape, was of insufficient amplitude.

This was partially cured by building a simple amplifier using the stabilised 12 volt supply provided to the instruments....

Even this was not 100% reliable, and eventually I resorted to a good old fashioned mechanical drive... worked beautifully!

Regards

Neil
 
Hello,

I have some questions regarding what everyone is using for speedo setups. I am running an electronic unit from VDO attached to an induction unit made by universal speedometer. Nothing but trouble! The speedo bounces around at low speeds and doesn't even out till 60. At first I thought is was the speedo, but after exchanging it the problem was still there. I have trouble believing it is the inductive coil as it is just a copper winding. I have changed the distance between the pickup and the magnets on the half shaft. Also the signal wire is fully shielded.

Stig
 
Hi Stig,
If you have the Audi 016 transaxle you can fit the electronic speedo transducer from the Porsche 944. It screws onto the original cable housing and fits with no mods. Robert @ RF gave me this info (see VDO speedometer post of May 03 2002). Unfortunately I am months away from saying it works
frown.gif
and can't push my chassis fast enough
smile.gif
. I see no resaon why it won't. (I think the Porsche speedo is also VDO). Good luck Dave
 
Hi all
I have the same problem on my MK111 with the SW speedo. It smoothes out at 140mph. But seriously I think there is a combination of problems here,
1. Is the resistance of the wire between sender and head unit. I think the amplifier is a good idea.
2. To run the cable away from any other cables in the loom to prevent EMF induction. A screened cable could also help to prevent this happening
3. Use at least 8 magnets on the drive shaft. To increase the generated number of pulses pere revolution.

Regards

Chris
 
G

Guest

Guest
Autometer makes a hall effect sensor, 16 pulses per rev. They claim 12v square wave output, although I measured ~7v but I may have not supplied 12v when testing...

Auto Meter (part # 5291) speedo sensor, has 7/8 FEMALE threads.

If the picture shows up below, the female threads on the right are 7/8 and screw onto speedo output on the transmission, the male threads on the left can be used to hook up a regular cable for things like cruise control, however it comes with a plastic seal covering the threads for those that do not need the mechanical output.

5291_large.jpg


Cost is ~$68 US, have no idea if it will work with a transaxle...

[ October 13, 2002: Message edited by: Greg C ]
 

Robert Logan

Defunct Manufactuer - Old RF Company
Stig,

The 944 speedo sender unit as mentioned by Dave does work.

When I converted my American Motorhome (RV) for use here in Australia I used a unit similar to the one in the picture above and it worked GREAT. These units here in Australia and are suitable for all US engines, the RV's got a little 460 ci FORD.

Best wishes,

Robert
 
Back
Top