200 Miles - Is it still a thing?

[GTGallop]

Use to be (late 80's through about 2005ish) I know it was a thing where cars and trucks monitored the last 200 miles of history to maintain engine performance. So if you switched fuel or made any modifications, then you had to drive 200 miles before the car really "learned" the new conditions.

Is that still the case? Or are cars learning faster and adapting to modifications faster than the previous 200 miles?

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[AzScorpion]

I know that once I tuned mine it took a good 2-3 tanks full to feel the full effect of it. I could tell right away it was tuned but the shifts and power seemed to be better over time. As far as switching octane I'm not sure as I did that at the same time 87-91

 

[RedlandRanger]

I know when I put a Holley Sniper EFI on my 73 Capri (best mod I ever did for driveability) - they said it took 20-30 mins for the computer to learn. So I'd guess things are getting better. As long as I leave it on, it will continue to learn forever, but it doesn't really change a whole lot since it has figured most things out.

 

[Porpoise Hork]

I remember reading somewhere that all of Ford's Ecoboost systems utilize a dynamic multiplier system called octane adjustment ratio (OAR) or something like that. The system uses multiple sensors to maintain consistent performance in all sorts of driving conditions and octane levels used. It will also adjust the maximum boost pressure, spark timing, and injector pulse width when a change to the fuel octane rating happens. For example filling up with higher octane or better quality fuel will cause the computer to make these adjustments in near real time. When resetting the ECU or flashing it with a tune file (also resets the ECU) triggers the adaptive learning mode and may take several hundred miles of driving to "re-learn" the driver habits.

* Found the article about the Octane Adjustment Ratio.
https://www.cobbtuning.com/ford-ecoboost-and-the-octane-adjust-ratio-monitor/

 

[VAMike]

I remember reading somewhere that all of Ford's Ecoboost systems utilize a dynamic multiplier system called octane adjustment ratio (OAR) or something like that. The system uses multiple sensors to maintain consistent performance in all sorts of driving conditions and octane levels used. It will also adjust the maximum boost pressure, spark timing, and injector pulse width when a change to the fuel octane rating happens. For example filling up with higher octane or better quality fuel will cause the computer to make these adjustments in near real time. When resetting the ECU or flashing it with a tune file (also resets the ECU) triggers the adaptive learning mode and may take several hundred miles of driving to "re-learn" the driver habits.

* Found the article about the Octane Adjustment Ratio.
https://www.cobbtuning.com/ford-ecoboost-and-the-octane-adjust-ratio-monitor/

IME it'll adjust the OAR immediately if you put in a lower octane and start getting knock. it takes longer for it to notice that you put in better gas because it basically change a little, see what happens, change a little more, see what happens, etc. And it can only really do that when the engine is under load because no (in-spec) gas will knock at idle or low load.

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