Speedometer adjustment, NO, not the odometer display :)

Hi,

My Corrado shows approximately 10-13 kmh more than the reset MFA display at Vmax. So, at 215 MFA, approximately 230.

I would like a relatively accurate display. Had something like this in mind:

Insert the needle over the pin, but not completely through it, until it's free. Remove the needle and reposition it a little further down. It should, theoretically, work, or am I going to have complete speed chaos?

I have a Passat 35i TDI speedometer. V Signal nat. digital.

Complete nonsense? - Then please don't hit.

Best regards,
arne

Hi Arne

I have twisted my tachometer so that it indicates approximately -6 km/h when stationary.
This is the presentation, roughly around 100, meaning he's going into detail there.
Instead of showing 50, it now shows 49, and instead of showing 151, it shows 150... I can live with that.
Within the 200 range, the speed would then be approximately 2 km/h.

You shouldn't necessarily compare your speedometer against the top speed!

In Germany, a speedometer can display up to 15% more, but under no circumstances can it display even 0.5% less!!
the refer to 50km/h
so, at 215, the reading is 230, which is about 7% too high!!
also super im rahmen!!

Just add 18 inches and it will fit again!!
laugh!!

@TDIBubi - You are probably right, but it doesn't make me personally happy when the speedometer shows 230 and I'm only 'just' doing 215...

@ulf - that's perfect. How did you do it? As suggested by 'blauäugig'?

Best regards,
arne

Hi Arne

First, carefully exactly determine the lecture time at 100 (using BAB-km-table and stopwatch, multiple measurements)!

Then somehow twist the needle around that specific thread to below zero.

My son doesn't have a needle (practical).
I first turned the needle to the left stop of the stepper motor, marked this position, and then marked 6 km/h "less" next to it. I then turned the needle on the (at the stop) shaft to that position.

Caution, Arne:

I also have a 35i tachometer
When I re-installed the blue and tried to put the tachometer back on, it kept dropping.
Once again, in a clear and understandable way:

Before detaching, lift the needle past the stop, allow it to swing freely (in my case, the position of the kilometer counter display), and remember the final position.
When I tried to put it back in its original position, it actually went further down when I pressed it, meaning it continued to go towards 220 on its own

I can't tell you the cause or the solution, I just wanted to warn you. Then I measured how much it sags and adjusted it accordingly, placing it higher so that it sags to the intended zero position...

Have fun with it...

Maybe there's a guide in the 'pointer base'?

But that's exactly how I intended it to be! Has it worked for you now?

Electronically, there's nothing we can do, is there?

Best regards,
arne

Just a bit of half-baked nonsense:

This device works electronically, meaning it receives impulses that it then processes to determine speed and distance. If you add a circuit that throws away a pulse after a certain number of impulses (which would need to be calculated), then you should be able to achieve a usable result - what do the experts say?

The display itself should be quite robust enough, or have enough buffering, to avoid being thrown off by the slightly irregular timing.

Best regards,

Jan

No, you don't have enough impulses per revolution.
If we have 1000 impulses per wheel rotation, of course that would work. But if, for example, we have 5 impulses per wheel rotation, and we 'throw away' 1 per rotation, then we have a 20% lower speed value. This is much too crude. One possibility would be to change the 'tor time'. D.h. if I change the time, for example, from 1 sec to 0.98 sec.
(Torzeit is the time during which the impulses are read).
Also, your distance tracker is also not working anymore.
Alternative: Although the speed signal is digital, the display is analog (i.e., in principle, an analog voltmeter). So, directly in front of the analog potentiometer for adjustment.

Hello Alois,

The display is NOT a potentiometer, but a stepper motor, therefore that won't work.

I would also not manipulate it every time the wheel rotates, but globally, for example, every 20th time. Discard the impulse.

That's clear, but I suspect that it will also be affected by the same problem as the speedometer, so it shouldn't be too inaccurate. One should also measure beforehand how accurate the distance display is.

Best regards,

Jan

I'm worried that the distance is already exactly correct internally (see Climatronic or VAG-Com), so the speed should also be accurate. However, to be sure that the speedometer never shows too little, it needs to be adjusted programmatically, so I think the only way is to change it through software.

Sebastian