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Old 01-24-2015, 08:32 PM   #8 (permalink)
Master EcoModder
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Join Date: May 2011
Location: Toronto
Posts: 263

Blueberry - '17 Mazda Mazda3 GS
90 day: 32.56 mpg (US)

EVO - '08 Mitsubishi Evolution MR
90 day: 23.82 mpg (US)
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Yeah. In any case I found throttle response and torque suffering enormously leaner than 14.5-14.6. Nearing 15s torque drops like a rock. Add as much timing you want, it won't help. On the dyno I lost about 20% torque at the wheels leaning mixture to 16.8:1 AFR with advanced timing. I found best cruising between efficiency and torque (balance) to be around 15:1. You can go leaner a bit but I really like torque and
Responsive throttle. I can just lightly press the pedal and pulse to desired speed without any downshifting or torque converter unlock. Whereas in with leanburn, the engine seems to struggle when going from lean to acceleration enrichment and causes downshifts. so I ended up with 14.65:1 dialed in for cruise. I really get good torque at 1800 rpm now advancing timing and adding a bit of fuel (14.2-14.3 afr vs 14.6 stock). i can hold speed at 1600-1800 rpm on a fairly steep hill now, not that I'm saying richer or holding speeds are better for efficiency. I still get great mileage at 50mph for a full time AWD car with 95% of the possible torque. I'm baffled how Hondas run in 1.4 lambda region without the throttle feeling like ****?

My friends brand new corolla gets 60mpg on the highway without lean burn and it is much heavier than the older lean burn Hondas as well. I think I will concentrate on other areas of engine management and tuning while meeting EPAs regulations (as a side effect).

Last edited by ever_green; 01-24-2015 at 08:42 PM..
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