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Old 09-11-2019, 10:02 AM   #8 (permalink)
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Gaptooth (retired) - '00 Honda Insight
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Gen-1 Insights
90 day: 54.26 mpg (US)

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Originally Posted by serialk11r View Post
If you have an Insight, sure :P

When I had my FR-S with an instantaneous mpg gauge (which I used to mentally calculate the load from), I realized that it is really easy to step too hard on gas in 6th gear and run rich.

In a heavier car (for the gearing/torque), this can be a huge problem. Cruise control would make the car run rich up hills!

I still like tall gearing, but you definitely have to be on top of your shifting game and have a careful foot to get the best out of it.
I found something quite interesting when poking about with Honda's K series. Turns out the engine in cars like the older Type R, TSX, Civic Si, don't actually go rich even at WOT. That's true of most stock engine maps. Honda chose instead to pull timing to prevent knock. Now, admittedly this also has a fuel economy impact, since your peak cylinder pressure is farther from optimal crank angle.

I have no idea how Ford chose to handle WOT with the straight 6, but food for thought, you want to be in the engine's most efficient range as much as possible, and its lease efficient range as little as possible. If there's an issue with enrichment or getting at a high enough load that timing is seriously retarded, there's always a downshift.

My 2 cents.
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