Thread: Hills=good mpg
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Old 01-03-2013, 01:13 AM   #3 (permalink)
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Location: Oregon, US
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ZoomFreakingZoom - '88 Mazda RX7 Convertible
90 day: 19.02 mpg (US)

Geo - '96 Geo Prizm Base
90 day: 32.42 mpg (US)
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Originally Posted by mechman600 View Post
It's true. Rolling hills provide a means for pulse and glide without annoying people behind you. As long as your engine load doesn't go too high on the uphill so that it switches to open loop (rich default fuel mapping).

Neutral coasting (or EOC if you are brave) helps more than DFCO on the down hills, unless of course the hill is too steep to do this safely because DFCO robs energy as the car has to turn the "dead" engine as you coast - more energy than the energy required if the engine was idling in neutral.
Yah, nuetral is best, but DFCO is better than needing to use the brakes; you have to retain some form of safe speed. I alternate between 5th, 4th, and 3rd before going to my brakes.
1988 rx7 convertible. Streetported, racing beat header and presilencer replacing all 3 catalytic converters. Atkins 6 port sleeves. K&N cone filter intake. 22mpg average, 27mpg max. Spreadsheet (updated regularly):
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