Keep on reading if you have access to an OBD-II reader and a fuel-injected vehicle
As mentioned in this meta post, I'm on a mission to collect data for mass air flow values at idle. With sufficient data, it should be possible to post an informed, objective response to the volumetric efficiency rule-of-thumb question.
It should take no longer than 15 minutes to obtain the readings, fill out the questionnaire and send it over. All results will be aggregated on Google Forms.
Here is the questionnaire (Google Forms)
Here is the chat room dedicated to this endeavour
- Mechanics.SE Username (self-explanatory, optional)
- Vehicle Make, Model, Year (comma-separated values are fine)
- Engine Type (gasoline or diesel, naturally aspirated or forced induction)
- Engine Size (how big is the engine, in liters?)
- What was the OBD-II readout for idle RPM with vehicle stationary?
- Was the air-conditioning on?
- Do you know if the engine use a mass air flow (MAF) sensor or manifold absolute pressure (MAP) sensor to provide the OBD-II readout?
- What was the OBD-II readout for mass air flow?
- What were the units for the mass air flow OBD-II readout?
- How old is/are the MAF/MAP sensor(s)?
Don't forget to hit Submit and thank you for your time!
All information provided will be made public at the end of this survey.
- Please take the readings with the engine at operating temperature. If you are unable to do so for whatever reason, please mention it in the "Other comments/remarks" field
- It is OK to post the expected values from an official service manual in lieu of logging data via OBD-II and the value(s) are in units of mass / time
- a generic Bluetooth/Wi-Fi OBD-II reader should be sufficient for logging the requested information
- This questionnaire is applicable for both gasoline and diesel engine vehicles
- It is not mandatory to take RPM/MAF readings with the A/C both on and off, but if you do that counts for two datum points
- Exact engine displacement is not critical, advertised engine displacement ought to be sufficient (4.991 L vs 5.0 L)