Lamda values aren't the best to go by since the window is very narrow of AFR range.
.80 lamda is 11.8 : 1 AFR
.85 is 12.5 AFR
.90 is 13.2 AFR

I can tell you my car loves ~13.2 WOT on 93 pump with zero knock & kclv @ 24.5ish

 

I've never seen an engine make more power running rich. Ever. 13.2 is magic for NA if you have an efficient combustion chamber. Boosted is a different animal.

 

Yep. Here I'm rich at 10.0AFR leaning out to 11ish above ~5200rpm🤓🙃

 

Keep in mind he's running an E-30 - E35 mix so the ideal AFR should be adjusted according to his mix to get the right ratio so he won't run lean at WOT

 

AFR as an absolute isn't super helpful unless you know what the fuel is. Wideband sensors don't care what the fuel is, they just tell you how much oxygen is left (ideally, but not exactly because it's very difficult to reliably and affordably determine how much oxygen is actually there - this is done by inference, not direct measurement). The real thing is to understand the species of hydrocarbons left over at the end of the combustion process so you can maximize CO2 and H2O fractions of the exhaust while still making good power. The rest of the stuff in the exhaust gas is junk and not particularly helpful (unless you want to run without a Kettering ignition*), but there are LOTS of branch chains left over even in a "clean" running engine. I did a bunch of homework in this space a long time ago while working on a wideband O2 project.

* many years ago Honda built a gasoline engine without a spark or compression ignition system that used left over highly radical hydrocarbon species to ignite the mixture. It worked, but never made it to production.

 

You should always use lambda. Lambda values will always be the same regardless of the type of fuel you are using (ethanol, gasoline, methanol etc).

 

Correct and I was responding to the above 2 quotes when they were mentioning the best AFR for I'm assuming running straight gas not a 30-35% mixture of ethanol with an octane rating of about 95. But like FilwithanF said he was monitoring his Lambda values and Sector 7 had upped his fueling needs at WOT because when we ran he was running lean on the top end and asked the tuner to make a revision and add more fuel to compensate for the ethanol mixture he is running at altitude.