lambda scale

on this lesson at 3:41 it’s stated that .95-.98 lambda is lean I thought it was said that anything below 1.00 lambda is rich and anything above it is lean ? Or did I understand that wrong ? And also could anyone explain what he said about turning an N/A on the leaner side

Have you done the quiz ? Lambda 1 is stoichmetric regardless the fuel type. if you go .99 lambda you're rich 0.1 % if you go 1.01 you're 0.1 lean. so anything 1< you're rich. 1> it's lean.

Miguel,

I believe I understand the cause of your confusion and can hopefully clear it up.

Lean and rich get used relative to various things.

For example:

Lambda > 1 is lean of stoich, lambda < 1 is rich of stoich, so compared to stoich AFR, that's what rich and lean mean in that context.

At idle or light throttle cruise, where 1 lambda is generally the target, the same could be true.

However, in the moment you're asking about in that particular video, Andre is talking about a naturally aspirated engine being run on a race track where it will be operated at full throttle. At full throttle, targets richer than 1 lambda are generally used to generate not only more torque, but to control combustion temperatures as needed. While .95-.98 wouldn't be considered lean at idle, it is lean compared to a target of say 0.8-0.9 lambda, which would be more typical of a naturally aspirated gas engine at full throttle.

I hope that makes more sense now, knowing that the context matters because rich and lean are generally used relative to the conditions and fuel at hand.