Brake Specific Fuel Consumption and A/F Ratio

[Phaseshift]

Anyone know these values for the 1zz-fe? Or even better, anyone know how to find these values for any engine? I'm working on some basic potential turbo calculations using my limited knowledge of elementary thermodynamics. :)

[Phaseshift]

Well, I used .5 for my BSFC and A/F of 10. Since I have a 1zz-fe engine, I used its cylinder dimensions for the calculations. I used 6psi for boost pressure, and used 6400rpm as the speed. My results showed an increase from 140 to 194 HP. Anyone find anything different? There was alot of assumptions I made, so it's only a estimate, not an exact answer.

[Tryan77]

"Phase shift?!" Hehe...are you an engineer or student? I had thermo a long time ago and cant be of too much help. I have just retained a minimal knowledge of the theory. Are you actually digging into the chemical reaction and energy release(chemII)? (effective amount of fuel burned, etc...)(or are you messing with the Otto Cycle) Anyway, sorry this post doesn't answer you question! :rolleyes:

[Phaseshift]

Originally posted by Tryan77
"Phase shift?!" Hehe...are you an engineer or student? I had thermo a long time ago and cant be of too much help. I have just retained a minimal knowledge of the theory. Are you actually digging into the chemical reaction and energy release(chemII)? (effective amount of fuel burned, etc...)(or are you messing with the Otto Cycle) Anyway, sorry this post doesn't answer you question! :rolleyes:

I'm an engineer. Graduated not to long ago. But my area isn't in combustions, it's more nano-mechanics and control.

I didn't do my calcs down to the chemical reaction. The lowest level calculations I did was the assumption of the Brake Specific Fuel Consumpion ( lb of fuel per horsepower per hour). I'm sure if I wanted to find the exact number, I would have to work with the chemical reation with the combustion chamber dimensions for each cylinder to the output at the crank. But.... I'm not going that far.

[Jesse IL]

You can't exactly figure out BSFC, you just measure it. Same with A/F. BSFC and A/F will generally fall into a range for certain types of engines, but the actual values will vary greatly depending on bore and combustion chamber efficiency and design. You can guess some values, but until you strap the car on the dyno and see what happens, you don't know what you got. Even things like headwork and work on the backs of the valves will have effects on these values.