My tuner gave me his AFRs
He is a well respected tuner and has a decade or so experience.
For non turbo it is 13-12.8
And turbo:
12.3 @ 0.5bar
11.5 @ 1bar
10.8-10.3 @ 1.5bar
Hope you can make something out of this Rev buddy
Thanks for that Skalabala makes alot of sense to me although I was looking at 11.3 at 1.3 bar , I will need to check my calculations with what you are saying.
Basically I have a K1 200v this is a small turbo pushing up to 1.27 x the ct9 air. When you have no more air to push one way you can get more power is to add fuel up to the point of optimum combustion. Which I think for the Starlet is about 11.3 afr for best rich torque at WOT.
There are other sides of the story to consider -
1 > If on boost depending on fuel , boost above a certain level will make det more likely. Kon on this site says don't go leaner than 12.4 on boost.
You may find different sources give various results for the boost that produces the quickest burn for a paricular fuel but your tuner is saying similarly with 12.3 at .5bar.
2 > Yes too rich causes less power because the most power produced is in the second stage of combustion and if you use too much oxygen in the first stage by using more fuel the second stage will not happen.
But
3 > Higher boost compresses the fuel which accelerates the combustion that is where the richer fuel comes in - ' Richening up the mixture results in a slower burn, moving the pressure peak later where there is more leverage, hence more torque. Also the pressure peak is lower at a later crank angle and the knock probability is reduced. The same effect can be achieved with an optimum power mixture and more ignition retard. '