[E92westy]

OK, these are my first stab at live data logging, so may not be that great..
Just trying to see if my MAF actually is on the way out before I shell out for a new one at £190(!) (or shove these under the nose of the dealer, I suppose).
Logged these at full throttle, second gear, warmed up etc.
E92 320i MSport, standard.





Second one is a bit smoother but still 'spikey' (?)...
Is this normal?

This last one is at idle after returning from the drive above.
Missed the labels off this one, sorry , blue line in revs, pink line is actual MAF g/s.



Thanks.

[F104]

Depends on temperature when you did this, but doesn't look way off..The MAF will likely have an integrated temp sensor.

In theory, if you pick 6000rpm, that is 100/second. On a 2ltr, 4-cycle, that's 100ltr/sec at 100% volumetric efficiency of the engine (which it will never have - i would say 90% is a realistic number).

Air is 1200gr/1000ltrs at 20C. So you expect to see 108gr/sec @ 6000 rpm if volumetric efficiency of the engine is 90%, and at 20C. More if ambient is lower.

cheers,

[E92westy]

Thanks for the in depth reply!
What I'm really after is if the line should be totally smooth or if a bit 'spikey' or 'bumpy' is ok.
Cheers.

[F104]

I'm no expert... I assume you would only see a nice fluid line from something like a speed (Hall) sensor, but not from these type of sensors. Nevertheless most deviations seems to be within 2%, which looks fairly good to me. What did you use to log, BT?

[E92westy]

An ELM 327 interface from the 'Bay of Fools'....
Seems to work well enough, however.