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Old 09-28-2008, 11:29 PM   #2 (permalink)
MetroMPG
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Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 22,275

Blackfly - '98 Geo Metro
Team Metro
Last 3: 70.09 mpg (US)

MPGiata - '90 Mazda Miata
90 day: 52.07 mpg (US)

Winter beater Metro - '00 Chevrolet Metro
90 day: 61.98 mpg (US)

Fancy Metro - '14 Mitsubishi Mirage top spec
90 day: 58.72 mpg (US)

Even Fancier Metro - '14 Mitsubishi Mirage top spec
90 day: 70.75 mpg (US)
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I can't tell you exactly how much throttle to use when accelerating, except to say my own technique has me shifting below that 3300 RPM mark the BSFC chart suggests is optimal for the non-XFi engine.

I'm more likely to shift around 2800-3000 RPM simply because I don't like winding the engine out, even if it is a bit more efficient.

That said...

If there's any chance you're going to have to brake or otherwise slow down shortly after accelerating in this manner, don't do it. Just accelerate gently and upshift as early as you can. Braking after brisk accel is about the worst thing you can do. (The best thing, speaking only of efficiency, is to shut the engine off and coast after accelerating - Pulse & Glide).

Re: the vac gauge, I've never used one in my car, but you're effectively describing "DWL" (Driving with Load), which I do regularly when highway driving (I've moved away from extended P&G cycles on the open highway). And the answer to your question is "yes" it's pretty normal for your speed to fall off on even modest inclines if you've picked a relatively low load target (e.g. inches of hg or instant MPG on the MPGuino or ScanGauge).
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Ecodriving test: Manual vs. automatic transmission MPG showdown



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www.MetroMPG.com - fuel efficiency info for Geo Metro owners
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