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Discussion Starter #1
Can you set AFR values in the Holley EFI software as Lambda?

I don't see anywhere to change from AFR to Lambda. I searched the Help and came up with one hit on Lambda.
 

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Discussion Starter #4
I like what I see so far, but inability to tune Lambda is a big knock. We switch between fuels (pump gas, E85, methanol) so tuning with Lambda is an absolute must.

Does the Boost Control and Water/Methanol control work? Can we hook a flow meter up to a meth injection line and if meth stops flowing add more gasoline to replace the methanol?
 

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I like what I see so far, but inability to tune Lambda is a big knock. We switch between fuels (pump gas, E85, methanol) so tuning with Lambda is an absolute must.

Does the Boost Control and Water/Methanol control work? Can we hook a flow meter up to a meth injection line and if meth stops flowing add more gasoline to replace the methanol?
Why?

Lambda is simply the ratio of the Stoichiometric number of the fuel being used and the actual A/F ratio. The ECM still needs to know the Stoich # which will certainly vary from fuel type to fuel type. You can set most any newer aftermarket ECM to target a specific A/F #.
 

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Why?

Lambda is simply the ratio of the Stoichiometric number of the fuel being used and the actual A/F ratio. The ECM still needs to know the Stoich # which will certainly vary from fuel type to fuel type. You can set most any newer aftermarket ECM to target a specific A/F #.

If you learn to tune in Lamba, you will not need to worry about what fuel you are running. It is a different A/F number for each fuel. But Stoich for each fuel is where you start.

Kinda like tuning in KPA instead of inches of vacuum then boost.
 

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Discussion Starter #8
Why?

Lambda is simply the ratio of the Stoichiometric number of the fuel being used and the actual A/F ratio. The ECM still needs to know the Stoich # which will certainly vary from fuel type to fuel type. You can set most any newer aftermarket ECM to target a specific A/F #.
Lambda is not a ratio. It is a number that tells you how far from Stoichiometric the tune is. It does not care what fuel you are running and all AFRs use Lambda as the root and are then multiplied by some number specific to that fuel.

If you start mixing fuels (i.e. methanol injection) then you can throw AFR out the window as it's useless.

If you learn what Lambda is and run or tune to multiple fuels, you will never tune to AFR again. Trust me.
 

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If you can enter an A/F ratio number in the software, for what stoich is for the fuel you are using, does that get you "half way" where you'd want to be. I understand if you mix fuels, you still aren't really there.

Unfortunately the typical American racer doesn't even know what lambda is. In Europe it is the common term vs "air/fuel ratio" here.
 

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Discussion Starter #10
If you can enter an A/F ratio number in the software, for what stoich is for the fuel you are using, does that get you "half way" where you'd want to be. I understand if you mix fuels, you still aren't really there.

Unfortunately the typical American racer doesn't even know what lambda is. In Europe it is the common term vs "air/fuel ratio" here.
Hi Doug,

Thanks for the reply. Since Lambda is the base number, if you gave an option to have a multiplier, one would just put "1.0" if they want to see the reading in Lambda (or 14.7 for gasoline, 9.7 for E85, etc). That would probably work.

Am I right?

And the A/F Feedback table could be populated using this number as well?

- Trever
 

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Hi Doug,

Thanks for the reply. Since Lambda is the base number, if you gave an option to have a multiplier, one would just put "1.0" if they want to see the reading in Lambda (or 14.7 for gasoline, 9.7 for E85, etc). That would probably work.

Am I right?

And the A/F Feedback table could be populated using this number as well?

- Trever
You could do just as you say.
 

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Lambda is not a ratio. It is a number that tells you how far from Stoichiometric the tune is. It does not care what fuel you are running and all AFRs use Lambda as the root and are then multiplied by some number specific to that fuel.

If you start mixing fuels (i.e. methanol injection) then you can throw AFR out the window as it's useless.

If you learn what Lambda is and run or tune to multiple fuels, you will never tune to AFR again. Trust me.
I can understand the value of lambda to a point but would you really consider it as the only viable solution for a multi-fuel tuning scenario? It seems that this assumes that for given load point, a common lambda value would be targeted for gas, methanol, or ethanol... or any combination thereof. Meth injection on a gas engine will definitely "throw off" an AFR expressed as a gasoline AFR, but I've not found that it does so to the point of worthlessness.

There are a few ways that folks describe or visualize Lambda. One is that it is the stoich ratio for a given fuel normalized to 1. Given this, I am not sure how observing measured AFRs as Lambda reduces or eliminates error when mixing fuels. The O2 sensor measures dissolved oxygen content in the exhaust stream and has no idea what fuel was burned to create the exhaust. Unless a wideband controller knows the ratio of the two different fuel masses being delivered to the engine and somehow accounts for this in its measurement, I don't understand how Lambda is perceived as a solution. What would be measured and expressed as a Lambda of 1 (or any other value) will change as different ratios of fuel combinations are applied to the engine.

In short, in a changing world of fuels, each with different stoich ratios, Lambda is NOT a constant. As long as you are comfortable tuning to the scale in which your AFRs are being displayed, that's the key.
 

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Well said Craig,

I would add the real benefit in using Multi-Fuel is really a flex fuel sensor capable of adjusting the target stoich for the particular blend. Now reading in Lambda would be beneficial as one could easily track the target A/F easier as the stoich changes vs the dedicated Gas vs E85 scale in a "Semi Flex Fuel" system as currently used by Holley. BTW, we alternate between E85 and Gas routinely (minimal blending) as fuel runs low....super easy...just flick a switch to the alternate saved profile and.......mission accomplished!
 

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I agree with you Dennis, a fuel sensor would be nice to have for those that need one, plus the ECM would need to be able to deal with the different types of fuels. I still don't see why people would want to tune by Lambda rather than looking at A/F ratios. They are telling you the same thing. My old Horiba AFR's had a switch on the front so you could instantly toggle from displaying A/F to Lambda. To each their own I guess.
 

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Discussion Starter #19
Back to my original statement: Lambda is not a ratio, it tells you how far from stoichiometric you are.

I am not implying that lambda is the magical equalizer of multifuel tuning. If you load a tune for gasoline and try to run E85, lambda won't correct a tune that is 40% off, but it helps you figure out "how far off you are".

For example: a gas AFR of 13.5:1 equates to a Lambda of roughly .92. Let's say you want to correct AFR to 12.5:1 which equates to about .85 Lambda. What does AFR tell you to do? It just says you need to add fuel. Normally you would add fuel until you hit the AFR you want, Right? A very unscientific method.

If you're reading lambda, it actually tells you "how much" fuel you need to add or remove to get the desired AFR. Subtract desired lambda of .85 from .92, multiply by 100 and you get a value of "7". This is how much fuel you need to add or subtract to your map. Add 7% fuel and you will be much closer to where you should be than if you are taking a stab in the dark with AFR.

Tuning with Lambda is incredibly faster to tune with since its already telling you how much your fuel map is off and can be easily and quickly correlated into a % change without requiring any charts or calculators.
 

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Why is it I see the old school guys live and Die by AFR? If they switch to E85 they just keep reading in Gasoline AFR on their wideband gauges, but just drop to a richer reading? I...really don't understand this method of thinking. Only thing I can say...as stated before. Most all people only understand AFR readings. Not Lamba. I understand both, but I don't see where it is a problem for Holley to program a drop down tab (or something) for you to select AFR or Lamba. As Trever stated, from a tuning standpoint.....it is much easier/faster to tune in Lamba.
 
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