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Thread: Semi-Open Loop: what's the fuel economy like?

  1. #1
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    Default Semi-Open Loop: what's the fuel economy like?

    I run Closed Loop (and PE enabled) and very happy with my fuel economy and power. I usually average 12-13L/100kms (18-20mpg). I've run full Open Loop before and quite happy with the engine's smoothness although fuel economy dropped to around 14L (17mpg) at best.

    For those running Semi-Open Loop what fuel economy figures are you averaging?

  2. #2
    Lifetime Member macca_779's Avatar
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    Highway I'm getting low 8's Overall average of city/highway with avg speed of 62km/hr I'm receiving 12.2L/100km. Commanding AFR using B3647 1200-2000 below 55ka of high 15's to low 16's:1

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    Thanks macca. Good figures for hwy.

    15-16:1 seems a bit lean for my car's need. It likes to run richer b/w 1200-2000rpm, low MAP.

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    Lifetime Member macca_779's Avatar
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    Quote Originally Posted by SSbaby
    Thanks macca. Good figures for hwy.

    15-16:1 seems a bit lean for my car's need. It likes to run richer b/w 1200-2000rpm, low MAP.
    The timing I'm running helps. For example @.40/1600 I command 30deg, for the same RPM ramp it up to 40deg @.08 Works well

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    Yes. Good timing helps fuel economy. I run slightly higher timing @ .40 but less @ 0.08 across 1600rpm.
    Last edited by SSbaby; October 18th, 2007 at 08:34 PM.

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    Bump. No more responses?

    If the number of responses is any guide, I can only assume that 14.63 stoich is not commanded much across most VE tables... It implies to me that semi-open loop (OS3) is not really worth running as it doesn't give any additional benefit over closed loop or open loop?

  7. #7
    Joe (Moderator) joecar's Avatar
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    (Semi-open loop does give you an indirect sanity check that your wideband was working right.)

  8. #8
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    Quote Originally Posted by joecar
    (Semi-open loop does give you an indirect sanity check that your wideband was working right.)
    Thanks Joe.

    I guess if the O2s get dodgey... I won't be replacing them with new ones. I'll just flash in OS3 and go Open Loop.

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