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Under Standing AFR

Understanding AFR

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Hi how would you go about the AFR when you add water meth injection on boost .Greg.

If combustion was stable and temps ok you could go slightly leaner. If fuel is no longer enough to maintain stable combustion anywhere near MBT you would probably stay fat.

Short answer is lamda or displayed "AFR" shouldn't have to change much.

It is a balance between combustion stability, component life and torque from fuel/air mass. If it doesn't self destruct you will make most power around 0.85 lambda (peak flame speed) but on most engine/fuel combos at decent specific output that is not enough fuel to maintain stable combustion and keep parts at workable temperatures. The more water/alcohol the lower the temperature, but it does reduce power. It depends on the application.

Hi Michael thanks for help on meth/water injection, I have just started on EFI tuning.