You might not feel it seat of the pants, but a load bearing dyno definitely shows a worthwhile power gain at part throttle.
Justin
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Ok I feel like a moron! Could one of you help me out a little, what part of the timing table should I adjust? And how far should I adjust those sections? I understand the diesel side of the house, but gas is much differant to me.
Tony
I would just add timing in the fuel mixture correction table. So it only adds timing in PE. I think that timing at part throttle cruise is fine the way it is stock, but the stock tune dosent have enough timing at high throttle/ pe mode.
What is PE mode?
PE= Power Enrichment mode, think of it as WOT mode where fueling is completely Open Loop via PE tables (and if negative? LTFTs fuel is added) and the NBO2s are disregarded.
So what adjustments should I make to the PE table?
Tony
You can start with probably about 2-3 degrees. Don't add more than that in the 3600-4800 rpm regions where peak torque is. So add a little more in the 2400-3400rpm regions becuase their is less airflow in thoes regions.
The stock tunes (especiall for trucks) always seem to drop timing as the rpms increase. For the stock cam (trucks) it looses a lot above 5400rpms so I think a lot more timing can be added above 5400 becuase airmass drops so much above that.
From what I have learned if air going into the engine is low you will need more spark advance but if you have more airmass going in their will be more compression and less timing needed becuase of the faster burn rate.
So basically a timing table should look about like an inverse of the ve table.
I hope this helps you.
I have a 2007 Chevy Express 2500 Extended Van /w 6.0L that I haul in.
I have the commanded AFR set at 15.5, added 4 degrees timing across
the board in the high octane table, made the dfco just a bit more
aggressive (couldn't do much because EFILive can not adjust the
cut off point on this vehicle), tightened the tranny, and did an auto-ve.
I went from around 13.5-14 to 17-17.5 so far. Oh yeah, the cats
somehow leaked out of the exhaust. I'm still looking for more though.
B5908 is the fuel spark correction table. It will add/subtract timing based on what air fuel ratio the engine is running at. Meaning it will add timing when in PE mode becuase in PE mode the fuel mixture is richer.