VDO speedometer

Bill Bayard · 05-03-02, 07:12 PM

Does any one know how to calibrate a VDO

speedo? It has the small LCD readout and the

black push button.

It is difficult to look at my handheld GPS

to see how fast I'm going, and drive at the

same time! Help!!!! Please!!!!

Bill

05-04-02, 06:42 AM

Congratulations Bill obviously you have your car on the road. Now the fun begins.

To calibrate a VDO all I think you have to do is take 5280 feet ( one mile ) divide it by the rolling diameter of your wheel ( say 6.5 feet - you will have to check this figure )to get the number of revolutions of your wheel per mile and multiply by 8 ( pulses per revolution of a Porsche gearbox ) = 6500.
Hold your finger on the black button and when it asks for imput key in the number.
Simple.
You can also check this by driving over a measured mile.........Stephen

dbache · 05-07-02, 01:59 AM

Hi guys,
I also have a VDO but many months away from calibrating it. Does anyone know how to get it to work with an Audi 016 Transaxle? Is there any adapter available or do I have to go to strapping magnets to a drive shaft?
cheers
Dave

Bill Bayard · 05-07-02, 06:47 AM

Dave,

The speedo sensor pulses a signal to the speedo each time the gears rotate, via
internal magnets in the gearbox. You will need to depress and hold the black button
with ignition off, then turn ignition on.
When the speedo reads pulse, release the
button for a few seconds, then it will read like a digital clock. Set the numbers, and
give it a test. Adjust according to your speed compared to another car. There are many variables to account for...Tire size,
# of magnets, size of gears, etc. The easiest thing to do is plug in a number and hope you get close, then tinker with it until it reads correctly. My setting reads
6600, and I have 255 rear tires. That works
for MPH. If you need KPH, the setting would be considerably lower than that. If you have
access to a portable GPS, that makes it a lot
simpler to accomplish. Good luck!

Bill

Robert Logan · 05-07-02, 09:36 AM

Dave,

The aluminium threaded insert that the spedo cable normally screws in to can be unscrewed and turned round. When this is done a Porsche 944 speedo sender can be screwed straight on to it and this will send the correct pulse to a VDO gauge. Cleaver people these Germans !!!!

Robert

dbache · 05-08-02, 08:40 AM

Hi Robert, pardon the ignorance as I am not familiar with Porsche. Does this mean I retain the nylon drive gear and shaft and the sender essentially fits on the end as would a normal speedo cable? This indeed would be a magic "fix" [img]images/icons/smile.gif[/img] many thanks Dave

Wayne Presley · 05-09-02, 03:03 AM

You can use a magnetic pick up and use the bolt heads on the inner CV joints to create the pulses. To calibrate, go to the VDO web site and there is a pdf manual for the speedo.

Robert Logan · 05-09-02, 06:58 AM

Dave,

Indeed you can keep the same plastic drive. This is a very simple conversion, literally the gearbox is fitted for either mechanical or electrical speedo drives. The 944 Porsche uses an electrical drive and therefore copy it for VDO and the Audi uses a mechanical speedo drive and therefore copy it for Smiths / SW .

As regards the VDO calibration we follow the instructions with the gauges and I have a 300kph speedo on my motorhome (I am nothing if not optomistic - actually I am looking for a long mine shaft with a favourable tail wind for the full power trial of the motorhome). The motorhome VDO speedo is accurate to more than 99% and although we offer them as an option we have only sold one set.

Best wishes,

Robert

jimbo · 05-10-02, 01:51 AM

Right, Robert, motorhome speed trials. Like my 240D years ago. If I had been going forward any slower, I would have actually been going backwards. As a friend once said, "the only way to make it go faster is throw it off a cliff. And you STILL have to shut off the air conditioner.."
Maybe a stretch GT40 with a motorhome center section...? next project?