What does AFR mean in UNCLASSIFIED

Air Fuel Ratio (AFR) is a numerical metric that represents the ratio of air to fuel in the combustion chamber of an internal combustion engine. The exact AFR number varies depending on the fuel being used and its octane rating, but it's typically in a range of 14.7-20.0 for gasoline engines or 2.0-2.5 for diesel engines.

Adjusting the AFR can allow engineers to optimize their engine for either maximum performance or maximum efficiency. For example, running a leaner AFR helps maximize power output whereas running a richer AFR helps with fuel economy.

Yes, there can be significant consequences associated with running either too rich or too lean mixtures in your engine. Too rich of a mixture can potentially lead to detonation due to increased cylinder temperatures while too lean might cause misfires due to lack of sufficient combustible material in the cylinder head.

At higher RPMs, more air needs to enter into each cylinder for better combustion so engines with variable valve timing or variable intake manifolds switch to richer mixtures as speeds increase in order to make sure that enough combustible material is present in each cylinder as well as boost overall power output.

There are several different ways that engineers can measure Air Fuel Ratios including wideband oxygen sensors, dyno tuning, and even data logging from existing ECUs within vehicles themselves. Each method has its own pros and cons depending on specific circumstances, so it's important for tuners and engineers alike to choose the best method based on their needs and budget constraints.