Anyone have a good way of measuring MAF voltage and airflow to develop the MAF curve?
05-24-2004, 11:46 AM
#3
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I was hoping to just do it on the car... log voltage with a multimeter and airflow with VAG-COM?
I realize that I won't be able to easily correlate the two... was thinking I could just pick 10-15 different evenly spaced MAF intervals(i.e., every 15-20 g/sec) and read the voltage at those intervals to get a relatively decent idea of the curve.
Not sure how I'd go about setting up a flowbench to measure the output.
-Dave Pramanik
Not sure how I'd go about setting up a flowbench to measure the output.
-Dave Pramanik
05-24-2004, 11:56 AM
#4
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doesnt engine block 000 show actual MAF-voltage in the first or second field?
You could just log vag-com and get a relation between the ECUs "grams/sec" and voltage...
Although I wouldnt count on that the ECU MAF reading in grams/sec actually is correct?
Although I wouldnt count on that the ECU MAF reading in grams/sec actually is correct?
05-24-2004, 12:13 PM
#5
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Nothing in there about MAF voltage, at least not for 2-bank systems (which the S4 is). The 4th field for 1-bank systems says 'Voltage' so that could be MAF voltage for those, but doesn't help me at all.
Why would the ECU MAF reading be incorrect? Shouldn't that be just based on the voltage and the MAF curve? I'm just trying to work backwards and get the curve.
-Dave Pramanik<ul><li><a href="http://www.ross-tech.com/vag-com/m_blocks/000.html">http://www.ross-tech.com/vag-com/m_blocks/000.html</a</li></ul>
Why would the ECU MAF reading be incorrect? Shouldn't that be just based on the voltage and the MAF curve? I'm just trying to work backwards and get the curve.
-Dave Pramanik<ul><li><a href="http://www.ross-tech.com/vag-com/m_blocks/000.html">http://www.ross-tech.com/vag-com/m_blocks/000.html</a</li></ul>
05-24-2004, 12:52 PM
#6
what you are planning on doing sounds reasonable...
or you could try to extract the transfer function out of the ecu file. in the link below is a stock S4 ECU file for an S4 in england.
have fun
<ul><li><a href="http://www.andywhittaker.com/Audi/ecu/index.html">http://www.andywhittaker.com/Audi/ecu/index.html</a</li></ul>
have fun
<ul><li><a href="http://www.andywhittaker.com/Audi/ecu/index.html">http://www.andywhittaker.com/Audi/ecu/index.html</a</li></ul>
05-24-2004, 07:59 PM
#7
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to do it right....its probably better to do it off the car....
but if you can find something you can log voltage vs. time with...hook it up to the car, start logging at the same time...and go from idle to max air flow...
of course unless you can max out your MAF on the car....your graph will be incomplete
of course unless you can max out your MAF on the car....your graph will be incomplete