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spark and afr

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Old Nov 28, 2023 | 01:08 PM
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Default spark and afr

what would you expect the afr (reported/wideband) to do if timing gets substantially reduced during wot? e.g. from 20° to zero?
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Old Nov 29, 2023 | 12:59 AM
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Originally Posted by Dian
what would you expect the afr (reported/wideband) to do if timing gets substantially reduced during wot? e.g. from 20° to zero?
I have seen dyno tests where over 10 degrees of spark variation made zero AFR difference. Not sure how much it would take to report a difference.
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Old Nov 29, 2023 | 01:43 AM
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that makes sence, since the decrease in power comes from lower pressure and a worse leverage on the piston. now, with a "massive" retard the fuel might not completelely burn, so the gasses would be richer? at least thats my way of reasoning.

the thing is, im seeing mixture leaning out considerably when torque management/traction controll retards spark. so i wonder if that is real. also what could be done about it n the tune.
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