Quote:
Originally Posted by Dmacc
Ethanol burns at a much cooler temperature than gasoline, and also has a higher equivalent octane rating, that's why you are able to lean it out more, because of its in cylinder cooling effects, as far as I understand.
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So the tuners are not tuning for Ethanols's stoich of 9:1 then.
Sounds like they are leaning out the pump gas AFR to get maximum power and relying on the cooling benefits of ethanol to supress any detonation.
Makes some sense at 30% E85 blends or so......but as you increase the amount of E85 I would think the lambda ratio would alter.
Aren't the O2 sensors in our cars based on a lambda of around 1?
In otherwords, they alter the amount of fuel until all the oxygen is effectively burned.
As you increase the % of ethanol in your mix, wouldn't you need less oxygen to achieve lambda since ethanol runs richer.
I don't think the O2 sensors know you are running E85......they just measure the amount of residual oxygen in your exhaust fumes.