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Old 01-27-2009, 11:58 PM   #112 (permalink)
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WonderWagon - '94 Ford Escort LX
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Originally Posted by OldGuy View Post
Here is a link to an article which is very helpful in understanding BSFC charts:

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Thanks, OldGuy. I thought that article link was one of the most useful and informative links in the whole thread.

Given that vehicle specific BSFC maps can be difficult (if not impossible) to find, perhaps the Averaged* BSFC Maps found in the article have some relevance.
...* Includes V8, V6 & 4-cyl engines.
diagrams are sourced from a 1999 report prepared for the Canadian government by Sierra Research of California. The diagrams are based on a sample of 1995 model year, naturally aspirated, EFI 2-valve engines


Here each dot shows the speed and load for a typical mid size car at 1 second intervals during the US fuel economy test. Of the time the car takes to do the test, just 5 seconds are in the island of best BSFC. Quite a few of the dots (the authors say that they overlay) are at worst BSFC idling at zero load with the car stationary!

Not sure that it's all that meaningful - but for purpose of comparison - here is scale-matched** overlay on the Saturn 1.9L Map including Doax's plot of HP/rpm from his Matrix.
...** The vertical scale is probably incorrect. The Average map's vertical scale is BMEP but I don't know how that relates to newton meters. I took BMEP for ft/lbs and scaled accordingly.

Last edited by TestDrive; 01-28-2009 at 12:33 AM..
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