russian wrote:
I am surprised no one has put that Miata MAF on an air flow bench - do not tuners use these and have these devices? If tuners use and have air flow benches that's what we need. Maybe the data is somewhere maybe it's worth asking a question on the Miata forums?
Yeah, I've searched and asked, everybody goes sd, it works well enough and easy to do so nobody has done this. I did get one data set from m.net
At some point in the future it would be awesome to set up a flow bench, not just for maf calibration but for headwork. Not in the cards right now
abecedarian wrote:
Not sure if it's been mentioned or considered, but even if you get raw transfer data, or frequency information, from a flow bench, that information is only valid on THAT flow bench. A change in duct shape or a bend, no matter how subtle, can create reversion which affects the sensor reading without actually affecting the net air flow.
The flow bench should have been calibrated with something else, a simple manometer and some math is enought to make sure things line up. The problem is building the thing.
kb1gtt wrote:Also, don't forget that flame front speed will cause the O2 to burn with Nitrogen, which will through off the O2 to air ratio.
About the %02, don't forget humidity will also displace 02's and change the % of O2 in the air. I think there might be a web page where you can get a feel for the how much O2 you can expect. I seem to recall a kind of map that showed several different measured points. I seem to recall such a map can be found with semi live data.
About pressure, that's less important. Your MAF will typically have a thermistor in it, which has a very low thermal mass, so it stabilizes with the intake are in a matter of seconds.
Nitrogen burning should not affect the reading more than 5%. Testing and comparing on lower octane fuel would be a cool test if this pans out.
The thermistor sensor itself is not what needs to heatsoak, it's all the intake piping. IAT's rise and fall as the car gets driven, affecting density and throwing the math off. IAT's should be pretty constant accross the test as long as the car is not being driven and warmed up.