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On an engine with with cam with a lot of overlap you should in theory try to keep the afr from say 13.97 idle and ideally 14.7ish then maybe at wot a little richer naturally aspirated
Is that a question or a statement? My thoughts -
With a lot of overlap one problem with AFRs can be a false lean indication. There are two basic reasons for this.
A small amount of unburned fuel-air mixture passes from the intake to the exhaust exhaust on overlap, and the lambda reads the oxygen as a lean mixture.
Sometimes a lumpy cam' can cause a light misfire because the quality of the fuel-air mixture is poor, or there is significant exhaust gas in the cylinder, and this misfire allows unused oxygen to pass through to the lambda and, again, a lean mixture is indicated.
A further complication is that adding fuel can make the situation worse, if the over-rich condition further compromises the combustion - using closed loop feedback to the ECU can lead to all sorts of problems because it may keep adding fuel to try and correct the false lean indication.
Personally, I'd like to have the AFR around 14.7 for hot idle, maybe a little leaner if idle isn't compromised, as running rich increases the possibility of bore wash, oil dilution, plug fouling, etc.
It was a question lol, sorry kinda wasn’t more clear and ran on lol. I was late and I was headed across the states. Thanks for the reply
