Quote:
Originally Posted by kennybobby
Have you done any coast-down tests to determine your Crr? At this speed rolling resistance is a big factor in the power curve.
In imperial units it looks like you are doing a 1/4 mile acceleration run from 0 to 45 mph--did you only shift once during the run? What is the time to reach 70 kmh for each of the runs ABC--from that you can calculate your power and relative fuel consumption compared to the blue lines on the BSFC chart.
Also you might want to make some runs at 30 to 50% load to see if the consumption is higher there and that the best economy peaks at 60% and not lower.
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from my tests again 60-75% load seems best for short distance acceleration aka. city driving. i trust my scangauge 2 fully, it is always right to +/- 0.1%. anything below 60% you will not accelerate properly for a typical 4 cylinder, so you spend less time cruising/coasting. higher than 80% load and my consumption just skyrocketed. A/F stayed stoich at 14.4-14.5, but it resulted in tremendous increase in airflow that called in for more fuel injection -> hence poor mileage at +80% load. im blaming the high lift cams that engage under heavy load. i think modern cars control pumping losses much better than they used to so i would go easy on the throttle.
the only case where i have seen low-moderate loads hurt mileage are on a 2.3 turbo RDX. it just seems that spending time in vacuum for acceleration kills trip mileage. so on the turbo car i accelerate with 1/3 boost (according to built-in boost gauge, i think thats 4-5psi).