[TestDrive]

Originally Posted by cfg83

Googled this :

BSFC challenge

Nice find. I thought the Excel chart was particularly interesting.

A couple of years ago, I used a Graham scanner to monitor engine performance over a full tank of gas, over 500 miles. I then reduced the huge file to a smaller set to plot my best approximation:



Now Excel is not very good about drawing areas so as a quick hack, I used 'bubbles" of different sizes to stack the relative BSFC. What is interesting is the small 'red dots', the highest efficiency metrics, overlap some of the formal BSFC data but also extends quite is[sic] outside on the low power range.

One hypothesis, speculation on my part, I suspect ordinary vehicle operation involves partial throttle operation that is not evident in the standard BSFC charts. It may be that partial throttle operation shifts the high efficiency, engine operations into lower speed ranges.

A second hypothsis is that "heretical mode," or as Toyota calls it energy recirculation mode, may change the load characteristics. This may also change the peak BSFC regions.