[Raimo5]

Hi,

As we all know, cars are produced with slight speedometer buffer zone so that displayed vehicle speed is slightly slower than actual ground speed.

As I like to drive at exact speed limit (but not faster!), if road conditions allow it, I would like to have my car show the true speed. How can I code/program this to my pre-FL G11? I have access to ISTA and also planning to set up ESYS. Not sure if I should go with BimmerUtility vs standard ESYS and its launchers. BimmerUtility seems more user friendly and intuitive so new users like me can get into coding and programming with ESYS more easily, but please feel free to corrrect me if I'm wrong or there are any other peculiarities.

Thank you

[jaramillo]

Need a launcher to perform that
At kombi BC_V_KORREKTUR

[Raimo5]

Thank you. I will set up ESYS when I have a moment and then dig around. I will definitely need a bit more guidance, so I'll let you know when I have it all ready.

[Raimo5]

Alright, so I got my Esys set up - BimmerUtility with Esys v22.10, full psdz v4.37.3. Car is G11 with i-level S15A-22-03-553.

When I read KOMBI coding and search for BC_V_KORREKTUR in BU, it will show up as expected, but values are not what I expected. It is not a toggle of aktiv or nicht_aktiv. If I change it to ohne_korrektur for example, actual ground speed is still the same, but heads-up display reads one km/h slower than speedometer.

Hope someone can give me a bit of guidance.

[Node]

You do realize that "true speed" will depend on many factors like air temperature, tire temperatures, tire pressures, etc. In reality you will never get "true speed", just because it's not possible. Well, even uneven road surface will skew it...

So, you will DEFINITELY not find a setting like toggle "true" vs "untrue". That is just not possible at all. If anything there will be a correction factor which you will need to spend time tuning, and then that tune will be good only for very SPECIFIC road/weather/tire conditions...

[Raimo5]

If outer rolling circumference remains unchanged, then how does the speed that is picked up by wheel speed sensor change related to environmental conditions? Only thing that will change the correlation between ground speed and displayed speed is the outer rolling diameter. That can change when different wheels/tires are fitted and not sized properly, or when there is significant pressure rise as the tires warm up during driving. I have RDC and most I have ever seen is .1 bar increase when tires are warm. This is absolutely negligible and will not increase rolling circumference enough to have any impact on speed readout.

If I set my speed to 53km/h, then I will do 50km/h ground speed no matter the conditions, provided that tires are inflated properly. What I want to do is code out that intended speed buffer. Whether it is a toggleable switch or a map is to be determined by someone smarter than me. Oh, and on E series, that is exactly how it worked. You flipped a toggle and it went from one map with speed buffer added to one without it.

[rikbrouwer]

[...]

As I like to drive at exact speed limit (but not faster!), if road conditions allow it, I would like to have my car show the true speed. 

[...]

YES! I would like to change this as well. It is one of the most irritating 'features' of my car that the indicated speed is always +3 from the actual speed. So 30km/h gps speed shows 33 on display, 130 km/h shows 133 on display. The difference is always 3km/h so the speedometer is actually very precise, unfortunately designed with this handicap. 
It shouldn't be a big deal to just compensate +3 one might think, but it is: Every time when the speed limit changes when on cruise control I have to press the speed +/- buttons multiple times: 60 -> 50 means should be hard press down ONCE. Instead it now is 5 button presses: 63 - hard press down - 60 - hard press down - 50 - soft up - 51 - soft up - 52 - soft up 53. This feels so stupid BMW designs this on purpose.
On the BMW i3 people tried to correct this before by coding the parameter above and some others but didn't find a solution yet. I'll keep looking.