ECU 'learning'
Discussion
I have seen on various threads about super unleaded petrol and air mass sensors that the 911 ECU needs to 'learn' the way you drive the car, what fuel etc to produce the right engine mapping.
Is this real?
How does it work then? does the ECU have a micro computer and storage to work all this out?
Koenig
Is this real?
How does it work then? does the ECU have a micro computer and storage to work all this out?
Koenig
Its very real.
Its not the air mass sensor that does it, its the knock sensor.
The ecu has a set amout of ignition advance that its allowed to add to its base settings, for any particular point in the map. The map is based on rpm and engine load (often calculated by throttle angle or air mass). The ECU will try to advance the timing until it detects knoack and then will retard from that point by a set amount. History plays a big part in some ecu's but I don't know if the Porsche one is dependant on history.
Normally, if you fill up with very good fuel and drive using all of the map, especially the bottom right hand bits (high load - high rpm), then it will advance. If it isn't, or is doing it very slowly, some ecus will lose the history with a 20 minute battery disconnect. Some don't.
Either way, it will eventually advance the timing and you will feel the gains.
1deg on a NA Porsche should be around 8 or 9bhp. Good fuel could give 3-4deg over normal unleaded.
Its not the air mass sensor that does it, its the knock sensor.
The ecu has a set amout of ignition advance that its allowed to add to its base settings, for any particular point in the map. The map is based on rpm and engine load (often calculated by throttle angle or air mass). The ECU will try to advance the timing until it detects knoack and then will retard from that point by a set amount. History plays a big part in some ecu's but I don't know if the Porsche one is dependant on history.
Normally, if you fill up with very good fuel and drive using all of the map, especially the bottom right hand bits (high load - high rpm), then it will advance. If it isn't, or is doing it very slowly, some ecus will lose the history with a 20 minute battery disconnect. Some don't.
Either way, it will eventually advance the timing and you will feel the gains.
1deg on a NA Porsche should be around 8 or 9bhp. Good fuel could give 3-4deg over normal unleaded.
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