EvoScan vs Boost Gauge Boost Reading?
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From: Malvern, PA
EvoScan vs Boost Gauge Boost Reading?
So i no this is kind of a silly question but, ill ask it anyways.
My JDM Map "Boost Logger" in EvoScan reads 1-2 PSI lower then my AEM Boost Gauge.
The AEM Boost Gauge is brand new and installed correctly. So with that being said what one would you take your boost reading from? Evoscan or Boost Gauge?
My JDM Map "Boost Logger" in EvoScan reads 1-2 PSI lower then my AEM Boost Gauge.
The AEM Boost Gauge is brand new and installed correctly. So with that being said what one would you take your boost reading from? Evoscan or Boost Gauge?
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From: Malvern, PA
trust the map sensor over the gauge.. and heres why. we have the map sensor in evoscan fine tuned for the atmospheric sea level.. so theres no way its going to read off.
my aem gauge does the same thing. the aem gauge is obviously set from factory so if you travel its not gonna be able to auto detect sea level changes. atleast i dont think it can.
my aem gauge does the same thing. the aem gauge is obviously set from factory so if you travel its not gonna be able to auto detect sea level changes. atleast i dont think it can.
My defi reads 1-2 off when it should read 0, car off key on. I'm with tscomp, I would assume the gauge is calibrated at a "middle of the road" setting for altitude where as the map is set for your specific altitude.
0-5000 ft elevation has a little over 2psi in difference..
0-5000 ft elevation has a little over 2psi in difference..
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Start with this thread, https://www.evolutionm.net/forums/ec...evo-8-9-a.html
And this is what you will look at/edit. It will take just a few seconds to tweak. I suck at this stuff and was able to change it. All credit goes to MrFred!
And this is what you will look at/edit. It will take just a few seconds to tweak. I suck at this stuff and was able to change it. All credit goes to MrFred!
Logging Boost in EvoScan or Mitsulogger
MAP sensors do not know the local atmospheric pressure. To log boost in psig (what all boost gauges show and what people always use to discuss boost values), the conversion formula for the logging program needs to have an offset for your local atmospheric pressure. The general formula for the OMNI 4 bar MAP sensor is:
0.2369*x-b
where b is the local atmospheric pressure. The local atmospheric pressure is affected strongly affected by altitude. For example the pressure at sea level is 14.7 psi, but at 5000 ft, the pressure is 12.2 psi. That's a big difference when you want to log boost. Use this table of altitude vs pressure to determine the offset pressure for your formula:
altitude (ft) local atmospheric pressure (psi)
0 14.7
500 14.4
1000 14.2
1500 13.9
2000 13.7
2500 13.4
3000 13.2
3500 12.9
4000 12.7
4500 12.5
5000 12.2
6000 11.8
7000 11.3
8000 10.9
*For example*, if you are living at 750 ft, then you'd want to use 14.3 psi as your offset, and the formula would be
0.2369*x-14.3
In the following instructions, please use your formula in place of the words FORMULA HERE.
For EvoScan 0.99+, the MAP logging definition in the Data.xml file should be changed to:
<DataListItem DataLog="Y" Color="" Display="OMNI MAP" LogReference="OMNIMAP" RequestID="38" Eval="FORMULA HERE" Unit="psig" MetricEval="" MetricUnit="" ResponseBytes="1" GaugeMin="-15" GaugeMax="35" ChartMin="-15" ChartMax="35" ScalingFactor="1" Notes=""/>
MAP sensors do not know the local atmospheric pressure. To log boost in psig (what all boost gauges show and what people always use to discuss boost values), the conversion formula for the logging program needs to have an offset for your local atmospheric pressure. The general formula for the OMNI 4 bar MAP sensor is:
0.2369*x-b
where b is the local atmospheric pressure. The local atmospheric pressure is affected strongly affected by altitude. For example the pressure at sea level is 14.7 psi, but at 5000 ft, the pressure is 12.2 psi. That's a big difference when you want to log boost. Use this table of altitude vs pressure to determine the offset pressure for your formula:
altitude (ft) local atmospheric pressure (psi)
0 14.7
500 14.4
1000 14.2
1500 13.9
2000 13.7
2500 13.4
3000 13.2
3500 12.9
4000 12.7
4500 12.5
5000 12.2
6000 11.8
7000 11.3
8000 10.9
*For example*, if you are living at 750 ft, then you'd want to use 14.3 psi as your offset, and the formula would be
0.2369*x-14.3
In the following instructions, please use your formula in place of the words FORMULA HERE.
For EvoScan 0.99+, the MAP logging definition in the Data.xml file should be changed to:
<DataListItem DataLog="Y" Color="" Display="OMNI MAP" LogReference="OMNIMAP" RequestID="38" Eval="FORMULA HERE" Unit="psig" MetricEval="" MetricUnit="" ResponseBytes="1" GaugeMin="-15" GaugeMax="35" ChartMin="-15" ChartMax="35" ScalingFactor="1" Notes=""/>
The one thing that is missing from the above is that you have to ensure that when the ignition if off the boost being logged is completely 0. Even with the formulas its often off by some .0001x or more. You log the car off and find out what its off from and then subtract that from the boost int he formula. When you log again with the car off the boost should now read 0.
I think that how to should be edited to say have x-0, log the car off with key to run, and use the number logged to subtract from x. It would be easier as I highly doubt anyone will be right on as posted above.
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