2015 2500HD 6.0L

Im sitting here having a nice beer (good enough to pour into a glass!) And browsing my stock tune...

11- 11.7 : 1 AFR for performance enrichment?

Like it makes sense due to variations in fuel composition and alcohol %.

There's gotta be some power left on the table lol.

I just leaned my PE out to what ive calculated to be...

11.8:1 from low rpm to middle.

11.9:1 middle to 5000rpm.

12:1 5000rpm to 6000rpm.

Its still pretty conservative but im trying to be a little safer with this engine. Especially since the VVT1 cam will be a knocking on my door soon.


Anyone have any opinion or experience with their changes to the PE AFR GM set out?

 

Stock is always rich, just to save their *** really.

The factory tune one mine went as far down at 1.330 on the EQ ratio or 11.03 afr commanded.

I leaned the whole thing out to 12.25 AFR across the board and it's been great ever since. I changed many other things aswell from the over sensative knock sensors and the burst knock tables that get in the way of things. Minor torque management changes and tuning the transmission.

 

Ditto.

I would invest in a wideband. Often times it's not a 1-for-1 ratio when changing values.

 

IF the MAF and VE tables are dialed in well, it is pretty close. If GM fudged the PE multiplier to mask a bad area in the tuning it will not be.

Wideband is the way to fly though. Either add it to the EGR position input or the Evap temp input of the PCM and tune away.

Running E10 fuel when I first start tuning, I set the Stoichiometric value to 14.1 and the PE multiplier to 1.20 from 2,500 rpm through redline. My initial wideband target is 0.83 Lambda. That is a fairly safe starting point. To get a few more HP some engines respond well as lean as 0.88-0.90 lambda. When you run that lean you have to be more mindful of timing and fuel quality. On straight gasoline with a 14.7:1 stoichiometric value 0.90 is 13.23:1 and 0.88 is 12.94:1. To know what the PE value is compared to Lamda, take 1 and divide by lamda. 1/0.83 = 1.2048

 

^ Lambda is the inverse of equivalence ratio, so 1/ER=Lambda. The factory PCM uses equivalence ratio.

The factory settings are meant for the worst case user...someone with their foot to the floor for a long time pulling a load up a hill.