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Old 12-11-2007, 09:06 PM   #7 (permalink)
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Join Date: Dec 2007
Location: Melbourne
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The Mighty Mira - '92 Daihatsu Mira
90 day: 61.32 mpg (US)
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Originally Posted by Lazarus View Post
Yes it does have a lock up converter. I don't know about the 62% but the max torque happens about 3200 rpm and that seem to work well for the acceleration portion.
I've drawn on the engine map to indicate how much power you want the engine to be producing relative to what it can do, and why.

Note that if you have a choice, via gearing, you want the engine rpms to be as close to 2300 as possible (assuming 4 valve/cylinder car). At any rpm, you want your engine to be loaded such that you are operating within the two bands I have drawn. I calculated the percentage of possible load on the engine as a percentage - stick around 65% and you should be fine. I'd guesstimate that would equate to 65% throttle, as the technique for actually mapping BMEP to throttle requires an accelerometer or dyno.

Note that 0 BMEP corresponds to a no load state on the engine, which is the same negative acceleration in gear as the equivalent neutral coast, which is just a bit above closed throttle.

100% BMEP corresponds to WOT.

Where 65% of the power generated by the engine is in terms of throttle, your guess is as good as mine, although at lower rpms there appears to be a drop off in BMEP near WOT.

I'd love it someone could actually measure this so that we could get a map of rpm versus TPS for 65% BMEP.

"Every body perseveres in its state of being at rest or of moving uniformly straight forward, except insofar as it is compelled to change its state by force impressed." - Isaac Newton

Last edited by newtonsfirstlaw; 12-11-2007 at 09:22 PM..
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