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PE for a cammed 4.8

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Old May 22, 2011 | 10:28 PM
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Default PE for a cammed 4.8

Anyone have any PE ideas/suggestions they would be willing to share?
All of my tuning so far has been on the street so its kind of tough to see what the truck actually likes. Right now I have it set for 12.2 from 0-2000 then 12.6 from 2000-4800 (judging by logged calculated torque 4700 is peak torque) then 12.8 from 4800 to 6000 and then richen it up a bit to 12.6 past 6000 (I don't spin past 6000 for now.)
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Old May 22, 2011 | 10:50 PM
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You don't need it that rich down low. The general idea is high 14s at idle/cruise, high 13s under low load, high 12s under high load for NA applications only. Should be a gradual increase to the richest setting, where it eventually levels out.
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Old May 22, 2011 | 10:55 PM
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Agreed, the fattest part of my fuel table is about 12.6, ten leans back out to 12.9 or 13.0
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Old May 22, 2011 | 10:55 PM
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So start lean and then richen it up on an NA setup?
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Old May 23, 2011 | 03:04 AM
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Start lean and slowly richen with RPM on any setup. NA just runs a little leaner through the whole range.
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Old May 23, 2011 | 06:23 AM
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I had it *** backwards...thanks for the pointers.
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Old Jun 9, 2011 | 11:47 AM
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Okay, I think I've got the hang of it - let me know if this looks a little more in line (see attached).
Attached Thumbnails PE for a cammed 4.8-pe-table.jpg  
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Old Jun 9, 2011 | 11:55 AM
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Well the way i have set mine up is the inverse of the cylinder airmass. Meaning as your grams/cyl goes up you richen up the afr and vice versa for when it goes down. Basically what everyone else was generically saying. Your fattest point should be at the highest grams/cyl. Same applies for fi. Very simple actually and it is not guessing

EDIT:
So if you use EQ Ratio, it would be the same profile as your grams/cyl,
If your using AFR, then it would the inverse of the grams/cyl profile.

Last edited by BlackGMC; Jun 9, 2011 at 12:10 PM.
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Old Jun 9, 2011 | 11:45 PM
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So more air means more fuel can be safely consumed.
I have another question about how narrow band o2's work. Now I know it is not advised to reference nb o2 readings for wot fueling, but I have read that the target is 890 to 900 mv. Up until now I've always thought that certain AFR will read a certain mv at the o2's but am starting to wonder if 890-900mv is actually showing that commanded and actual are in line?
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Old Aug 11, 2011 | 10:33 AM
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Originally Posted by smokeshow
You don't need it that rich down low. The general idea is high 14s at idle/cruise, high 13s under low load, high 12s under high load for NA applications only. Should be a gradual increase to the richest setting, where it eventually levels out.
Sorry for bumping an old thread but I didn't see any reason for a new one. What rpm are you hitting your richest setting at?

I'm tuning a 2011 5.3 and GM has it so rich that I'm surprised it doesn't smoke like a diesel at WOT.
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