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Closed Loop target - 086 | Closed Loop Fuel Control

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just watched the webinar on the Closed Loop Fuel Control, very well done, very informative. Curious about the settings on the Lambda Target table.

Are the entries to this table always 1.0 or does it get tweaked for those areas that you know you want to run a little rich or a little lean? Where do the initial settings for this "target" come from? Manufacturer, experience, the guy next door?

Do you have an example of a good target table?

Again, job well done


Depends really on your engine and application . For example if the car is stock or with minimum mods you will be chasing 1 at idle and cruise . Maybe on also an engine that haves a few more performance upgrades you might also be able to get 1 . But if you have a heavily modified N/A engine or boosted engine you might need to chase a richer ratio even on idle and cruise .

As you increase rpm you will need to go richer . A good way to start is to start richer and then move accordingly to see how your engine responds .

This has to be set up on either wideband stoich mode or auto mode and use a wideband sensor and in the Link G4+ you can go to the drop menu type AFR Target and it will send you to the AFR Target table where you can put you targets .

I would say the lambda of one really comes from the manufacturers need to maintain catalytic converter operation/efficiency. This is not really a concern for most of us though. However it is a good afr starting point for idle and cruise - good fuel economy and stable operation. You can run a little leaner for even better fuel economy or may need to run richer for better idle stability if you have aftermarket cams due to the increased overlap.

Hi Paul. As HS Engineering has mentioned, the target of lambda 1.00 is primarily for minimal emissions and cat efficiency. It does however correspond with close to optimal fuel economy too. You can see a small improvement in fuel economy by targeting around 1.03-1.05 lambda however in my own experience the gains are minimal.

If you want to learn more about choosing the correct AFR as well as some reasonable starting points for common engines and learn how to test and find the correct AFR for your particular engine, I'd suggest our Understanding AFR course.

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