Wide band reading vs megasquirt

showtime603

New Member
Dec 22, 2019
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mississippi
Hey guys.. have a question.. my wide band seems to match exactly what tuner studio is seeing at idle and at cruise.. when I go to make a WOT pull or roll into boost a bit.. I swear the gauge in the car is reading leaner than what it has on the data log.. is it possible the gauge in the car just isn’t reading it out as fast as it’s being logged? For instance, I feel like I’m seeing 12.0-?11.9 but then when I look at the log it gets to 11.8-11.7 or so.. I have had to adjust the voltage to get the wide band in the car and tunerstudio to match up. But that was done at idle and cruise.. I didn’t know if I also needed to adjust for wide open throttle and if so, how? Make a pull log it and see if they match up? Maybe I’m over thinking it a bit?
 
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Blown88GT

Founding Member
Nov 13, 1999
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Palm Beach Gardens, FL
The difference is likely due to the speed (or the lack thereof) of the Megasquirt. The control loop is not that fast because it doesn't have to be fast. You will always have a difference in readings because they are not synchronized.

If you're interested, here's a NASA paper which discusses control theory for a jet engine (specifically p.3).
Not all that different from a car.
 
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