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VDO speedo calibration
john_p_b - 31/7/05 at 08:47 PM

i'm officially scratching my head over this one guys. reading the instructions it says i need to drive a mile at a constant speed in order to calibrate my speedo. well 1. where in this day and age can you drive at a constant speed for 1 mile and 2. there is the slight matter of road legality.


anyone got any ideas?


bob - 31/7/05 at 08:56 PM

I jacked the back of my car up and stuck some axle stands under it,fitted one of those push bike speedos calibrated to the wheel size and drove the mile


spaximus - 31/7/05 at 09:26 PM

If you get the instruction book out it will show you how to enter a pulse figure and how to work it out. On my westfield with 195/50/15 tyres the pulse figure was 5200 and sailed through SVA. If you havent got the full manual contact joe cooke at Siemens vdo in birmingham who will send you the sheet. hth


mark chandler - 31/7/05 at 09:27 PM

Dual carriageways have mile posts, book an MOT at the end of one and calibrate on your way there.


stevebubs - 1/8/05 at 12:20 AM

yhm


givemethebighammer - 1/8/05 at 08:43 PM

I measured a mile in the tin top. Then drove slowly round the same route in the seven. Pushed the button when I started and again when I finished - easy.

ps I have a VDO speedo too.

It tested as being spot on at the SVA too,


john_p_b - 2/8/05 at 05:29 PM

well i've got it working to a fashion!

set it by entering pulse setting and at the moment it's reading a bit high i think, hold it at 3000rpm and it's reading 80ish mph. some working out and adjustment and i think it'll be ok BUT.....

it climbs! had the car up on blocks to run it up as i didn't want to take it on the road so i know not the best way to do it but i found that as i went through the revs and held it at 3000rpm in 5th the speedo would move pretty fast until about 65 then slow right down but it would creep all the way up to 80ish.

anyone got any clues why?

another thing is how many magnets should i be using? i started with 4 but the speedo was going mental so i changed to 1 magnet but that wasn't going to work! at the moment i have 2 but i'm sure i should be using 4?

sorry for all the Q's


givemethebighammer - 2/8/05 at 08:38 PM

I have 4 equally spaced around the drive shaft flange. Mine was not working right so I moved the sensor slightly further away from the magnets and found it cured the problem.


john_p_b - 3/8/05 at 04:35 PM

do you know what the pulse setting is on yours? took mine out for a drive today and i'm a mile out...... well actually about 12mph out. reading 18 when i'm actually doing 30


givemethebighammer - 3/8/05 at 09:25 PM

Not sure, I just followed the instructions and pushed the button at the start and finish of the mile. If I remember it was about 300 something pulses over the mile. However I have 14" wheels and 18560 tyres. I know what you mean about not wanting to take it out. I did mine one quiet Sunday afternoon round the estate and I drove very slowly ! They may let you set the speedo on the SVA centre rollers, I think this has been allowed before ?


john_p_b - 4/8/05 at 06:03 PM

shouldn't be too much of a issue now, had a chat with the wonderfull guys at A.B. BUTTS in leicester today, i can get it on the rollers there which will make sure it's 100% spot on!


givemethebighammer - 5/8/05 at 07:36 PM

I didn't know they had a rolling road at AB Butt. Thought they just sold stuff for carbs ?


john_p_b - 6/8/05 at 10:25 AM

it's quite amazing the gear they have in that place! it's not a power graph type rolling road though, it's one that purely used for calibrating speedometers. i should have thought of it sooner really seeing as we send all our trucks from work there to be done!