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Pumaspeed X-37 Hybrid Turbo Thread

grnmachine02

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But your wideband is still going to read 14.7 no matter what fuel you're using. It doesn't know or care what ethanol percentage you use. It only reads air.

At least this is how it has been explained to me for years. Many, many years.

edit:// I should say add that this is the case with the NGK widebands i've been using for ever. I confirmed this with an NGK rep. I suppose other systems will function differently.

double edit:// Well, perhaps I've been fed wrong info for many many years lol. I never blew anything up at 12.5:1 on e85, and made a ton of power. Interesting.
 


BoostBumps

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COBB Tuning Manual - Tuning for appropriate Air to Fuel ratios (Lambda)

Tuning for Appropriate Lambda.jpg

[HR][/HR]

Fuel Scalar Stoich. Setpoint

"This value is used to adjust the target stoichiometric AFR for fuel calculations.

Tuning Tips - This value can be used to correct fuel trims for alternative fuels. (ex. E-85) Lowering this value will lower a positive STFT/LTFT closer to 0%, raising this value will raise a negative STFT/LTFT closer to 0%. In the tuning guide we have provided a reference chart with approximate values for varied ethanol content".


ATR Scalar Set point.jpg
 


Hijinx

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But your wideband is still going to read 14.7 no matter what fuel you're using. It doesn't know or care what ethanol percentage you use. It only reads air.

At least this is how it has been explained to me for years. Many, many years.

edit:// I should say add that this is the case with the NGK widebands i've been using for ever. I confirmed this with an NGK rep. I suppose other systems will function differently.

double edit:// Well, perhaps I've been fed wrong info for many many years lol. I never blew anything up at 12.5:1 on e85, and made a ton of power. Interesting.
If lambda is 1, the wideband reports 14.7. So it goes.


Some Guy On The Internet
 


BoostBumps

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Maybe I'm confused here, but a lambda of 1 for any fuel means that stoich is achieved. In other words, you can't have a rich lambda that is equal to a fuels stoich. I think this chart is wrong.

Some Guy On The Internet
I believe the chart is correct...Its referenced in COBB's tuning manual along with further explanations regarding scalar recalibrations which might help clarify things...

COBB Tuning Manual - Tuning for appropriate Air to Fuel ratios (Lambda)
 


grnmachine02

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If lambda is 1, the wideband reports 14.7. So it goes.


Some Guy On The Internet
Now that I have thoroughly confused myself via google, let me see if I can makes sense of this. So e85 or E30 or E whatever, may be stoich at "insert number here" but the wideband will report 14.7 because at that point Lambda will equal 1? Yes? I thought i had a firm grasp on this lol.
 


Hijinx

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I believe the chart is correct...Its referenced in COBB's tuning manual along with further explanations regarding scalar recalibrations which might help clarify things...

COBB Tuning Manual - Tuning for appropriate Air to Fuel ratios (Lambda)
Ok, I'm picking up what you're putting down. It's a reference chart for fuel settings. The chart is likely correct for it's intended usage. However, stoich on any fuel = lambda 1.


Some Guy On The Internet
 


Hijinx

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Now that I have thoroughly confused myself via google, let me see if I can makes sense of this. So e85 or E30 or E whatever, may be stoich at "insert number here" but the wideband will report 14.7 because at that point Lambda will equal 1? Yes? I thought i had a firm grasp on this lol.
Yes. The short of it is widebands report in gasoline (E0) AFR. If lambda is 1, the reported AFR will be 14.7.


Some Guy On The Internet
 


grnmachine02

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Yes. The short of it is widebands report in gasoline (E0) AFR. If lambda is 1, the reported AFR will be 14.7.


Some Guy On The Internet
So going off of that, can we assume that a 12:1 aft on e30 is just as safe as 12:1 on gasoline? I'm just referring back to the vdyno Pete posted earlier.
 


BoostBumps

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Ok, why am I the only person who can't get afr and boost to show up in vdyno?
V-Dyno needs to be setup correctly in order to display AFR and Boost Profiles..

Open V-Dyno Program

Select "Files"
Select "Options"
Select Tab "Columns and Profiles"
Check "AFR" box and type in box Actual AFR (AFR)
Check "Boost" box and type in box Boost Pressure (PSI)
Click "Save"

Then Load your file and it should now show Boost and AFR profiles
 




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