[John K]

My mildly modded V2 will not follow the air. As the DA gets better, the ET gets slower. Usually indicates a lean condition.
My Aeroforce guage says a/f ratio is .99. What the hell does that mean? A/F ratio on most cars is about 12.5/1.

 

[Karch]

You need a wideband sensor and meter, in case you didn’t know that.


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[PGA2B]

Do you have HP Tuners or do you have a tuner?

If it is reading .99 that should be lambda which is fine for normal driving but certainly not for WOT.

 

[MeanMike]

My mildly modded V2 will not follow the air. As the DA gets better, the ET gets slower. Usually indicates a lean condition.
My Aeroforce guage says a/f ratio is .99. What the hell does that mean? A/F ratio on most cars is about 12.5/1.

Lamda is "A/F ratio"/stoiciometric. So, 1.0 lamda is stoichiometric. So, if you like 12.5 on gas, that would be 12.5/14.7=.85.

I personally like .80 = 11.7 on gas.

The advantage to lamda is it's the same no matter what fuel you're burning. So, with pure e85, 1.0 lamda is 9.3 a/f. And if you have any mix of ethanol and gas, stoich is still stoich for that mixture. You can more or less ignore ethanol content.

Without knowing exactly what you're looking at on the aeroforce, you could be seeing equivalence ratio. That's what GM likes. It's 1/lamda. So 12.5 = .85 lamda = 1.18 EQ.

 

[kittyboy]

I run 10.5-11 AFR high octane gas at WOT. I realize the images don't represent the whole picture, but thought to add them for reference. The plugs are 3k. I leaned my tune just slightly, a little rich shown here, but am mindful about #7 and #8 cylinders running hot, so I keep things a little rich to mitigate the lower denominator.

 

[John K]

Thanks for the info.

 

[random84]

I run 10.5-11 AFR high octane gas at WOT. I realize the images don't represent the whole picture, but thought to add them for reference. The plugs are 3k. I leaned my tune just slightly, a little rich shown here, but am mindful about #7 and #8 cylinders running hot, so I keep things a little rich to mitigate the lower denominator. View attachment 160701 View attachment 160702 View attachment 160703

Not bad - just leaving a few HP on the table.

On 93 pump, peak torque should be around 11.5 AFR. Peak "lean torque" around 12.0 AFR. Basically .78 to .8 lambda is a good target.

Being too rich can lead to excess fuel in the ring lands and bits breaking off, but you're probably fine. If you're getting KR, it could be overly sensitive knock sensors or just too much timing for what the motor wants.

Fuel also takes up space, along with occupying ring lands as said, and rich mixtures can induce pre-detonation potentially.

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[kittyboy]

Not bad - just leaving a few HP on the table.

On 93 pump, peak torque should be around 11.5 AFR. Peak "lean torque" around 12.0 AFR. Basically .78 to .8 lambda is a good target.

Being too rich can lead to excess fuel in the ring lands and bits breaking off, but you're probably fine. If you're getting KR, it could be overly sensitive knock sensors or just too much timing for what the motor wants.

Fuel also takes up space, along with occupying ring lands as said, and rich mixtures can induce pre-detonation potentially.

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Good info, thanks!

 

[kittyboy]

Not bad - just leaving a few HP on the table.

On 93 pump, peak torque should be around 11.5 AFR. Peak "lean torque" around 12.0 AFR. Basically .78 to .8 lambda is a good target.

Being too rich can lead to excess fuel in the ring lands and bits breaking off, but you're probably fine. If you're getting KR, it could be overly sensitive knock sensors or just too much timing for what the motor wants.

Fuel also takes up space, along with occupying ring lands as said, and rich mixtures can induce pre-detonation potentially.

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Forgot to ask? Is the range you suggest still a good air/fuel range running 93 in consideration of some issues I've read about regarding the rear #7 and #8 cylinders? ty

 

[07GTS]

if ur using the LSA e67 ecu then u can take advantage of the injector cylinder bias, the rear 7 and 8 u can make a percent richer if they need it

 

[kittyboy]

if ur using the LSA e67 ecu then u can take advantage of the injector cylinder bias, the rear 7 and 8 u can make a percent richer if they need it

Thanks! I never knew that, I am definitely going to check out that feature. Do you have a preference with regard to tuning those particular cylinders?

 

[07GTS]

i know some use it on the LSA for the stock setup which can help, just work out the right cylinders based on the firing order and alphabet i havnt done much on mine as i tried it and my earlier ecu didnt like the changes so had to go back, the e67 can use them tho

 

[07GTS]

''cylinder gain'' to be right, here is some info about it Any experience w/ "Injector gain vs cyl" ECM 12313

 

[Lt1z]

I have never found this to actually work if moved from 1.0 in testing.

Unlike aftermarket ECUs.

 

[random84]

I have never found this to actually work if moved from 1.0 in testing.

Unlike aftermarket ECUs.

This. Using cylinder bias seems to really do crazy stuff from what I've seen on HP tuners.

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[07GTS]

make small changes and only to that table IF it needs it, if ur ecu dosnt like it u will notice pretty quick my symptom was i could drive around normal but soon as i done a big throttle mash the engine just cut like it turned off then once i was off the throttle it was back to running, like hitting a limiter