lambda is a ratio
Phi is a ratio
Where they become an equivalence ratios is:
actual AFR/ target AFR. The ratio of two ratios, giving a defined point at which they could be equal.
Ford uses lambda/lambse, but just as you don't go 1/1,2/1,3/1 and instead go 1,2,3 you can ignore the "/1" that is lambse. Hence Ford uses lambda.
GM does lambse/lambda so instead go 1/1,1/2,1/3. you can multiply by 2, but ford does that, so divided by 1/2, you can multiply by 3 but ford does that so divide by 1/3.... you can't ignore the lambse part in these equivalence ratios. Hence GM uses equivalence ratio.
Dodge uses Phi. Phi is just fuel:air instead of air:fuel so 14.08:1 becomes 1:14.08. or 14.08 becomes .0710. Hence Dodge uses Phi. They don't use 14.08 for their stoich point of E10, so it will be some different value when you look over in that sub forum.
Bill it is already posted on page 1, it's a continuation of a problem the customer never replied back to.. Looking at the math previous calculations based on previous diagnosis
" I have been tuning on this stang for a while it is a stock 2016 with a vortech kit stock pulley auto car and has been running great doing whats its supposed to until we put a boss 302 and jba long tubes on it i deleted the imrc, the rear o2s and the evap....."
now the car is commanding insane amount of fuel took a sceen shot any one know wth is going on
using equivalence ratio command .637 and based off the WB EQ bank 1 1.03 (14.5) bank 2 1.05 ( 14.7) this would be lean and that is the 68% fueling requested to reach .61 which is what was commanded.
Last edited by mstang_man; 05-07-2019 at 04:50 AM.
Oh ok I didnt see anything posted tune or log wise I only saw a screen shot. This might help me fix a friends 15 mustang he is having similar issues with his trims and his commanded being way off. It was ok on a 150 shot but he moved up to a 200 and now it’s off. He’s running a boss Intake as well.
Murfie,
so using the setup as you described how does the information look here in the attachment, In this i take this error numbers and Multiply by half
When you are looking at LTFT, as you are, the entire view works ok. Just keep in mind LTFT works out of KAM cells that define ranges of air flow, so it works on sections of the transfer. It becomes important when looking at graphs of it. You can just disable LTFT and use STFT and skip the complication. You could also use LTFT+STFT. Its not uncommon for LTFT to swing +/-15% to keep STFT at +/-5%. So if your MAF transfer is already close, the former method would be preferred. The last thing you want to do is chase your tail, so if you have a known good transfer, or you find your self applying values less than 2%, just stop.
If you want to start to target certain sections of the transfer like WOT or a "constant as possible" 30% throttle light accel, STFT and veiwable range, or exporting the viewable range to an entirely new, shorter log, so you can use the entire view, allowing +,-, and A if needed. Is what I would recommend.
You are applying a smooth curve to best match actual flow over all. Don't get too caught up in making it choppy to fit what you are logging.
The only time you would look at the commanded lambda/ measured lambda, is if you were working on some of the open loop correction tables. Basically it can be ignored if you have a good transfer, Fords math is quite robust to allow this.
So here is snap of a pull i did, and for this i showed all 3, EQ ERR, STFT, LTFT hopefully all this helps others out as well. This Is a JLT CAI, good MAF File
Last edited by mstang_man; 05-08-2019 at 06:57 AM.
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