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Old 05-12-2008, 03:12 PM   #25 (permalink)
MetroMPG
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Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 22,515

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

MPGiata - '90 Mazda Miata
90 day: 52.71 mpg (US)

Even Fancier Metro - '14 Mitsubishi Mirage top spec
90 day: 70.75 mpg (US)

Appliance car - '14 Mitsubishi Mirage ES (base)
90 day: 52.48 mpg (US)
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Quote:
Originally Posted by monroe74 View Post
I'm also very intrigued by the possibility that WOT is optimal, and better than 70-80%, despite what I've heard about the penalties of open loop.
I'll just chime in an say that I also have doubts that the "rule" against going into open loop during P&G applies to all cars.

I've never spent much time watching loop status on the ScanGauge, except when I was initially curious to see how much time it took to switch over after a cold start. (Answer: in the depths of winter, no more than about 30 seconds).

But a couple of weeks ago, I called up that gauge while I was doing my usual P&G routine, and to my surprise, when accelerating I was in open loop most of the time! The transition point was much shallower than I had assumed.

I haven't tried to compare the difference between P&G with open vs. closed loop, but I will say that for my car at least, it doesn't appear to be a massive penalty. Consider the 104 mpg fill-up I saw last summer was using mostly open loop pulses (based on what I saw recently, using similar technique).

It definitely bears looking into.
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Project MPGiata! Mods for getting 50+ MPG from a 1990 Miata
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