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      01-04-2009, 01:07 AM   #23
Edman951
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Drives: F10 550xi, Alpine white
Join Date: Nov 2006
Location: Montreal, Quebec

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BimmerRob08,
It's like J08M3 said.
MAP sensor (Manifold Absolute Pressure)
MAF sensor (Mass AirFlow)

The S65 V8 M3 uses a MAP sensor.

If you wanna learn more on these sensors readup on them on Wikipedia.
http://en.wikipedia.org/wiki/MAP_sensor
http://en.wikipedia.org/wiki/Mass_flow_sensor

Map sensors don't see changes in engine volumetric efficiency as well as MAF.
Since BMW tuned the DME according to it's factory tested % of engine volumetric efficiency, with required values to make there performance requirements.

Now adding a few extra % of volumetric efficiency on a engine from a exhaust and air filter. The DME doesn't see them as well with a MAP sensor and cannot adjust the fuel for optimum performance.
But the engine has safeties built in so you don't damage the motor from leaning out.
By using the integrated 8 knock sensors and 4 O2 sensors.

Now this is what i know, but i don't know all the DME functions and tune. As i'm no tuner.
Maybe tuners on here will clear some of this up.
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