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Old 07-09-2014, 06:31 PM   #42 (permalink)
Frank Lee
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Join Date: Jan 2008
Location: up north
Posts: 12,762

Blue - '93 Ford Tempo
Last 3: 27.29 mpg (US)

F150 - '94 Ford F150 XLT 4x4
90 day: 18.5 mpg (US)

Sport Coupe - '92 Ford Tempo GL
Last 3: 69.62 mpg (US)

ShWing! - '82 honda gold wing Interstate
90 day: 33.65 mpg (US)

Moon Unit - '98 Mercury Sable LX Wagon
90 day: 21.24 mpg (US)
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Shifting causes all the engine's momentum to be lost, only to be brought right back up again as accelerating-that takes fuel. On carb'd stuff the sudden closure of the throttle can cause the mix to go rich- that is why VW fitted their carb'd cars with vac operated throttle dampers- so the throttle would gradually close and not cause an emissions spike. It is easy to skip shift and still remain in the BSFC sweet zone; usually there are just more gears than needed. More gears are nice for very heavy loads and steep hills but the rest of the time are not needed.
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