Anyone know how to figure out an equivelant BSFC?
07-25-2003, 10:26 PM
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Re: Anyone know how to figure out an equivelant BSFC? You can make an attempt at monitoring it using the following formula (the validity of the result will depend on how close your sensors are to ideal)
HP = IFR * 8 * DC / BSFC
BSFC = IFR@(Baro-MAP kPa) * 8 * InjDutyCycle / HP
(if you use HP values from a chassis dyno the values will not be comparable to normal BSFC values).
Alternatively you can try using the delivered torque paramter on the pcm as such
BSFC = IFR@(Baro - MAP Kpa) * 8 * InjDC / (Torque * RPM / 5250)
The units are normally expressed in lb/(hp*hr) (in the US anyway) - depending on what units you use for your injector flow rate, well, you will get the resultant BSFC in terms of those units.
I have no idea how accurate the formulas above will be, as I have never tried them - but without an engine dyno that is the best you can do.
You can replace the fuel injector term (IFR * 8 * injDC) with your MAF rate and calculate your BSAC the same way also.
Chris
HP = IFR * 8 * DC / BSFC
BSFC = IFR@(Baro-MAP kPa) * 8 * InjDutyCycle / HP
(if you use HP values from a chassis dyno the values will not be comparable to normal BSFC values).
Alternatively you can try using the delivered torque paramter on the pcm as such
BSFC = IFR@(Baro - MAP Kpa) * 8 * InjDC / (Torque * RPM / 5250)
The units are normally expressed in lb/(hp*hr) (in the US anyway) - depending on what units you use for your injector flow rate, well, you will get the resultant BSFC in terms of those units.
I have no idea how accurate the formulas above will be, as I have never tried them - but without an engine dyno that is the best you can do.
You can replace the fuel injector term (IFR * 8 * injDC) with your MAF rate and calculate your BSAC the same way also.
Chris
