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Old 07-19-2013, 02:38 AM   #6 (permalink)
bestclimb
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Join Date: Oct 2009
Location: South Central AK
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escort - '99 ford escort sport
90 day: 42.38 mpg (US)

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Quote:
Originally Posted by jeff88 View Post
So basically when accelerating, I should try to accelerate at around 4k RPMs. This has two benefits: best BSFC as well as get up to speed faster so I can than cruise. My question though is the BSFC is in g/kWh, not necessarily MPG, so the engine may pollute the least at 4k, but not necessarily be the most efficient in fuel used?

If one was to research a cam reground for economy use rather than street racing use, what would one be looking for?



Could this be done with an Arduino and tapping into the ECM?
AT WOT, at less than WOT slightly lower RPM is likely what is called for. At very high loads the computer is likely fueling via the fuel map which is less effcient than consulting the O2 sensor. An MPguino or ultra/scan gauge will tell you what is more efficient.

Quicker acceleration at a high GPH will get you up to cruise speed and high MPG sooner. Where the most efficient balance between quick (high GPH for short time) and slower (low GPH for a long time) acceleration is best evaluated with some sort of instantaneous fuel consumption display.

4000 very likely not an efficient cruise RPM due to it being efficient at lower power settings and being at a speed that is high drag. it is probably close to a decent shift RPM for getting up to speed fairly efficiently and quickly, but without a BSFC map, and/or observing some instant data.

Efficient and polluting are two different things. one is using the fuel smartly the other is not burning it enough (hydrocarbons in the exaust), or too much and creating NOx. your catalytic converter and computer should be taking care of that.
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