Once tuned, will a car run at 14.6 AFR in most situations?
#1
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And then at the commanded afr (based on the PE modifier) when close to full throttle? This is assuming a MAF tune.
How much variation is there? thanks
How much variation is there? thanks
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There can be some variation, especially with LT's since the O2's rarely work as they should with them. Even after extensive experimentation, my car tends to run a little lean when stoich is commanded - 14.85 to 15.00. Not an issue as there are not cats to protect. In PE mode, it's pretty much as commanded.
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#10
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12.5 is not lean....its usually a little on the rich side for WOT..
Try optimum at WOT closer to 12.9-13.1 on most of our naturally aspirated ls engines...
When you start to look at where our engines make power and when it starts to loose power..you will come to an understanding of what is lean and what is not..
I've seen combos that make great power with no detonation at
14.0..... If its safe, its not lean... It's just leaner than another combo might be.
Rich or lean is only relative to the combo it is with..
You start rich..,add timing until it stops getting better, then start removing or adding fuel until it makes the mist power..
Most people assume they are lean when they haven't even pushed the fueling to see what it really wants...
Rich and lean are not arbitrary numbers...and you can't call one afr or another rich or lean without the whole picture.
Example: my combo....12.9 @27* at WOT...
11.2 compression...
I ran a 10.97@123mph on Nitto Tires....and a stock 10 bolt with 3.42's
12.9afr is not lean for my combo.
Try optimum at WOT closer to 12.9-13.1 on most of our naturally aspirated ls engines...
When you start to look at where our engines make power and when it starts to loose power..you will come to an understanding of what is lean and what is not..
I've seen combos that make great power with no detonation at
14.0..... If its safe, its not lean... It's just leaner than another combo might be.
Rich or lean is only relative to the combo it is with..
You start rich..,add timing until it stops getting better, then start removing or adding fuel until it makes the mist power..
Most people assume they are lean when they haven't even pushed the fueling to see what it really wants...
Rich and lean are not arbitrary numbers...and you can't call one afr or another rich or lean without the whole picture.
Example: my combo....12.9 @27* at WOT...
11.2 compression...
I ran a 10.97@123mph on Nitto Tires....and a stock 10 bolt with 3.42's
12.9afr is not lean for my combo.
#12
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then when PE enables the commanded fueling will follow the PE table (note that PE can enable at part throttle, look at the PE Enable table).
Instead of thinking/viewing fueling in AFR, use EQR or Lambda, these will put rich/lean into easier to see perspective.
Any variation (barring noise) will be due to the airmass source (MAF or VE) not being correct (not modelling the actual cylinder fill airmass).
#13
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12.5 is not Lean for Forced Induction of your motor wants to be there...
I have a buddy running 14psi with super charger and an air to water intercooler.... WOT, 12.5:1 AFR.. no issues...
and you can easily fix the #7 issues with proper steam venting...just buy the Kurt Urban fittings and take all the steam plugs to a higher position...
its only a problem because its a hot spot because steam gets trapped there.