My attempt at writing a script for MPG from Map

[RichardP]

I know it's not perfect, but it may be a starting point for someone brighter than me.

It gives a reasonably accurate readout compared to tank fill and mileage on my cavalier.

2 user variables need to be set in the first 2 lines.

Rik

[Shon@PPE]

Nice, hopefully we see some more scripts posted soon.

[Philc]

Thanks for creating this script- I need it as my car doesn't monitor 'SAE.MAF'.

however, when I attempt to import, I get "Invalid Pid Script File!". I am able to import other scripts.

Is it possible to paste the body of the script in this thread?

thanks a million!!
-Phil

[RichardP]

var Cap = 2.2; // USER VARIABLE engine size in litres (edit to your engine size)
var FT = 75; // USER VARIABLE Variable for fine tuning result according to your own calculations from tank mileage, normally between 60 and 90, 75 is a good base to start from.

var VE = FT / 100; // volumetric efficiency of engine
var KIAT = Obdii.GetPidValueMetric("SAE.IAT") + 273.15; // convert metric IAT to Kelvin scale
var IMAP = Obdii.GetPidValueMetric("SAE.RPM") * Obdii.GetPidValueMetric("SAE.MAP") / KIAT; // Intermediate MAP value for calculations
var DAM = 8.314 / KIAT; // divisor for air mass
var MM = 28.97; // Molecular mass of air
var CF = IMAP / 120; // one fill cycle every 2 revolutions and convert RPM to per second value
var CMAF = CF * VE * Cap * MM / DAM; // Calculated MAF Value


   Obdii.PidValue.English = Obdii.GetPidValueEnglish("SAE.VSS") + 0.001 * 2686.5 / CMAF; //MPG (US Gal) For UK gal replace 2686.5 with 3198.2
   Obdii.PidValue.Metric = Obdii.GetPidValueMetric("SAE.VSS") + 0.001 * 1137.1 / CMAF; //km/l