AFM & MAF Specs

[CrazyJew89]

Alright guys. I have started working on making a proper MAF conversion for my car without chipping the ECU :D. I have a collection of the parts that I need to do this, including: a Ford MAF, Bosch MAF, and Ford air temp sensor. However, I am lacking some information about the signal coming from the MAF, the AFM, and the temp sensor that I will be using.

Bosch MAF:
Bosch #: 0 280 213 011
BMW #: 1 730 074
Need the voltage vs. mass flow

Bosch AFM:
Bosch #: 0 280 202 082
BMW #: 12866159
Need the voltage vs. air speed

Walbro Ford MAF:
Walbro #: AFH70-04B
Ford Service Part #: F5VF-12B579-BA
Need the voltage vs. mass flow

Ford Air Temp Sensor:
Need the resistance vs. temp

I have searched high and low on the internet and called BMW and Bosch for this information and gotten nowhere :mad:. If anyone has any of this info or has any ideas on where I could go to get it that would be very helpful.

[CoClimber]

I've been thinking about this and was considering making a small logger that would track the output of the two sensors - the AFM and the MAF. My 325 does not have an airbox - just a cone filter so I could attach the MAF before the AFM. I could then map the output of the MAF to the AFM and thus convert the output voltage of the MAF to be the same as the AFM.

Forgive me if I'm not being too clear. I'm in bed with a cold.

[CrazyJew89]

I've been thinking about this and was considering making a small logger that would track the output of the two sensors - the AFM and the MAF. My 325 does not have an airbox - just a cone filter so I could attach the MAF before the AFM. I could then map the output of the MAF to the AFM and thus convert the output voltage of the MAF to be the same as the AFM.

Forgive me if I'm not being too clear. I'm in bed with a cold.

Thats very similar to the route that I was gonna take. But I was looking for the signal specs of each sensor because the MAF measures mass of air entering while the AFM measures pressure. So I was gonna use the temp sensor with some math to convert it and that way I would be able to account for temp changes without having to remap it everytime the temp changed.

You would want to put the MAF after the AFM to minimize the air turbulence coming from the cone filter.
What would you use to log the voltages though because you would have to log 3 voltages at once (AFM, MAF, and Temp)

PS: You are perfectly clear and hope you get over the cold soon

[CoClimber]

I would probably use an Arduino board because I have a few with an EEPROM wired in. I haven't looked at the math yet - I'm still trying to get my car running.

I was also thinking about throwing an accelerometer in there and log my laps in autocross.

[CrazyJew89]

I wasnt even thinking about the microcontroller yet. I was talking about a way to get a time versus voltage graph for all three voltages at once.

Also I have recently become aware of several problems with using this approach. Apearanlty the AFM maxes out at about 70% load and the computer guesses from there on out, so I'm not sure what to do about that.

If you want to check it out I have a decent thread about this on r3vlimited.com. It has the same title as this one and you shouldn't have any issue finding it.