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?

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

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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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.

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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

Yes. Good timing helps fuel economy. I run slightly higher timing @ .40 but less @ 0.08 across 1600rpm.

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?

(Semi-open loop does give you an indirect sanity check that your wideband was working right.)

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Originally Posted by joecar

(Semi-open loop does give you an indirect sanity check that your wideband was working right.)

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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. :notacrook: