Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - The BSFC chart thread (post 'em if you got 'em)

abently · 09-26-2010, 07:58 AM

A quick question regarding live BSFC data.

Is it possible relatively speaking, to judge whether BSFC is better or worse, by comparing RPM and duty cycle change?

I.e, say at 60km/hr, rpm is 1800, and duty cycle is 14% in 5th gear, and in 4th gear, rpm is 2000 and duty cycle 13%, therefore an increase in rpm of 11%, and a decrease in duty cycle of 8%.

Meaning, on those relative changes, 5th gear, cruising at 60km/hr would be more fuel efficient?

I should point out, that these numbers are just out of thin air... and I'm assuming fuel pressure doesn't rise, with different load?

I'm also assuming the instrument error margin is constant and linear across the range being measured, for rpm and duty cycle.

Any potential holes you guys can see?

09-26-2010, 07:58 AM	#168 (permalink)
abently EcoModding Lurker Join Date: Sep 2010 Location: Australia Posts: 80 turquoise - '97 Toyota Starlet 90 day: 41.46 mpg (US) Thanks: 2 Thanked 4 Times in 3 Posts	A quick question regarding live BSFC data. Is it possible relatively speaking, to judge whether BSFC is better or worse, by comparing RPM and duty cycle change? I.e, say at 60km/hr, rpm is 1800, and duty cycle is 14% in 5th gear, and in 4th gear, rpm is 2000 and duty cycle 13%, therefore an increase in rpm of 11%, and a decrease in duty cycle of 8%. Meaning, on those relative changes, 5th gear, cruising at 60km/hr would be more fuel efficient? I should point out, that these numbers are just out of thin air... and I'm assuming fuel pressure doesn't rise, with different load? I'm also assuming the instrument error margin is constant and linear across the range being measured, for rpm and duty cycle. Any potential holes you guys can see?