Air fuel ratios for nitro methanol mixtures. A maxed out, blown alcohol engine runs an air/fuel ratio around 3.1 to 1. That is 3.1 pounds of air to one pound of methanol. In contrast, a maxed out, blown top fuel engine running 90% nitromethane methanol runs an air/fuel ratio around 1 to 1. That is one pound of air to one pound of fuel. after 3 passes N/A on a new motor i had a best et of 12.7 .with a A/F of 12.9:1 at 28 deg timing .jetted 50 shot and dropped to 12.1 et with a A/F of 11.9:1 , leaned it out by dropping fuel pressure and ran 11.7 et with a A/F ratio of 13.0:1 when i pulled or added timing et dropped so 28 deg was the ticket for that jetting . hope it helps. A/F ratio is a more precise tuning standard. While a 0.002-inch jet change can have a big effect on A/F ratio, keep in mind that the engine is flowing 12-14 times as much air as fuel. Youll have If I remember the old tune, it was around 12.8 to 14 AFR during normal driving, and at WOT it would drop into the low 11's. Just got it back with new tune, ready to roll and dyno pulls putting it at 340 at the wheels, but I notice my AFR on start up is at around 14.5 and within 60 seconds drops to 10.0 and holds there. This is why a wideband air fuel ratio gauge is such a must-have for carburetor tuners. Unlike a narrowband air fuel ratio gauge, the wideband air/fuel ratio . Air/fuel Ratio as an additional tuning indicator. The fuel mixture can be numerically controlled with an air/fuel ratio value. Air/fuel ratio is a combustion engineering standard measured as the weight of air to the weight of fuel. For racing, the air/fuel ratio would be based on the stoichiometric ratio plus an amount of richness for the fuel 3) Tune-up. The tune-up activity is the act of ensuring the burners are properly mixing the air and fuel and of reestablishing the most appropriate amount of excess air throughout the operating range of the boiler. a) Tune-up each operating position of the combustion control system (from high-fire through low-fire). Lambda to AFR Conversion Formula and Its Variables. The conversion formula for Lambda to AFR is quite straightforward: AFR = λ x. Stoichiometric AFR. In this equation, λ is the Lambda value representing the air-fuel equivalence ratio, and the Stoichiometric AFR is the ideal air-fuel ratio by mass, which is 14.7 for gasoline engines. Two- and four-barrel carburetors feature individual adjustments for fuel mixture. When it comes to tuning or adjusting a carburetor, the aim is to balance the air-fuel ratio, the mass of fuel delivered per mass of air, balancing power output, fuel economy, emissions, and engine longevity. Option 2 - Disable NN and use Volumetric Efficiency Tables (VE): From the few I have seen the factory VE tables need a lot of work. Cold start tables also need work. a - set desired AFR. b - disable baro learn (has been said to be a complete multiplier for tune and may cause uncontrollable swings)

how to tune air fuel ratio