Hondata

Hi Guys,

I would like to change from gas to ethanol but I'm not sure if I should use AFR or Lambda.

I'm using a NGK AFX wideband right now and know that if my wideband display varies from what Hondata is showing I have to change the voltage compensation so I can match the wideband's display with what hondata is logging.

What do you guys recommend to tune on Ethanol, AFR or Lambda?

Will my NGK AFX read the same values on both fuel types? I ussually tune to a 11.5 AFR on C16 on my NGK AFX, do I need to shoot for the same values on Ethanol if I keep my NGK AFX?

If you prefer to tune on lambda, how do you guys know if you have a wideband that displays AFR that you are logging the correct lambda values if you are using Ethanol instead of Gas?

We find is easiest to keep the same AFR settings and tune using 'gasoline air fuel equivalent'. eg stoichiometric shows 14.7:1, even though the actual stoichiometric ratio is around 9. The ideal AFR may change a little, but this is easier than re-learning a new range of ratios for ethanol.

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Hondata

Hi all,

I'm tring to tune close loop for Ethanol E85 on a european Civic type R running PRA K pro and narrowband.
Even If I change all lambda values to 9.7 instead of 14.7, close loop mode change fuel values to reach 14.7

Where can I change 'gasoline air fuel equivalent' ?

A quick run down on how air/fuel ratios work.

Oxygen sensors always measure the mixture as lambda. Stoichiometric is lambda 1.0 for any fuel. The last sentence is the important concept to grasp.

An air/fuel ratio is always derived from the mixture lambda. For gasoline stoichiometric is usually given as 14.7:1 (although is really is between 14.0 and 14.1 for US fuel). We'll use 14.7:1.

E85 (which may or may not be 85% ethanol - it varies from 65% to 85% ethanol) has a nominal stoichiometric air fuel ratio of 9.7:1, but the stoichiometric lambda is the same as gasoline, or any fuel for that matter, at 1.0.

So if you change to E85 for closed loop tuning do nothing. Keep the target air/fuel ratios at 14.7:1, because the lambda still needs to be 1.0 for correct stoichiometric operation. Use an overall fuel change or bigger injectors to supply the extra 30% of fuel, but closed loop operation does not need to be changed.

If you wish change the settings to lambda and it will make more sense.

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Hondata