Brake Specific Fuel Consumption (BSFC) Maps
From EcoModder
Brake Specific Fuel Consumption Maps
Useful for determining at what load and rpm your engine is making the most power out of the fuel given to it.
Ford 2.0L Zetec
Geo Metro 1.0L original
Geo Metro 1.0L cleaned up
1st Gen Honda Insight 1.0L
CVT, which would have lean burn if the car tested was a Japanese-market Insight. Electric assist does not appear to have been accounted for, so the high-load, high-RPM BSFC is grossly underestimated.
On a chassis dyno with a lean burn capable manual transmission equipped vehicle, with no evidence of reduced BSFC at the low load, low RPM regime where lean burn operates:
Saturn 1.9L DOHC
Skoda Felicia 1.3L MPI (50kW)
Subaru EJ22 2.2L SOHC
Toyota 3.0L V6 1MZ-FE and possibly the 3.0L 3VZ-FE (Previous Engine)
Toyota 1.8L 1ZZ-FE
Toyota Prius 1.5L 1NZ-FXE
Toyota Prius 1.8L 2ZR-FXE 2010-
Volkswagen 2.0L 5 cyl diesel
Volkswagen Jetta TDI 1.9L ALH 1999.5-2003
Each curve represents a constant horsepower developed by the engine. If you are driving on a given road with a constant grade, speed, and ambient conditions, regardless of which gear you are in, it requires roughly the same amount of power to overcome aerodynamic drag, rolling resistance and driveline losses. Therefore, regardless of what gear you're in, you're riding anywhere along the same blue curve; exactly where you sit on that blue curve being only dependent on the gear you're in and therefore the RPM at which the engine is turning over.
In the case of the TDI BSFC chart, if I take the example of operating on a certain speed such that the power is 20 HP, the lowest BSFC occurs when running at the gear that corresponds to about 1250 RPM. If I run at either a higher- or lower RPM from this point, my BSFC will increase. This is about the only point in the entire engine map where it would be disadvantageous to operate at an even higher gear if one were available (lower RPM) because of the worsening BSFC. Almost everywhere else, the lowest BSFC is achieved at the lowest possible RPM at a given power.
Volkswagen Jetta TDI 2.0L 2009
