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Old 07-29-2013, 01:18 PM   #242 (permalink)
some_other_dave
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Quote:
Originally Posted by WD40 View Post
what I really want to know is how to understand what its showing.
Can someone explain how to read it?
It is three graphs on one page. Each graph uses RPM for the X-axis, but they all have different measurements for the Y-axis.

One line is the maximum torque produced by the engine--at WOT (Wide Open Throttle). This is the one that goes roughly across the middle of the page, and its Y scale is at the right. It ranges from about 12 kg*m at 1000 RPM, to just under 18 kg*m at 5000 RPM.

One line is the maximum horsepower produced by the engine at WOT. This is the line that goes up to the right, and its scale is at the left side of the page. It ranges from less than 20 HP at 1000 RPM to just over 140 HP at 6500 RPM.

The line near the bottom of the page is the BSFC at WOT as well. Its scale is also at the right of the page. It looks to go from just over 250 grams/horsepower*hour at both 1000 and 6500+ RPM, down to about 220 gm/hp*hr at 3000 RPM.

This last line is what we, as efficiency enthusiasts, are interested in. But it isn't enough information (there is NEVER ENOUGH INFORMATION! ) because it only tells us about WOT. To determine the best acceleration range, we would need a BSFC map that shows BSFC at all throttle positions, not just WOT.

The graph is helpful, but a full map would be much better.

-soD
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WD40 (07-29-2013)