2018 trackhawk stoich (UK vehicle)

[rich24v]

Looking through some of the engine data displays the other day, I noticed that at hot idle
AFR sits at ~13.7 which I thought was a bit weird as stoich for petrol is 14.7
I pulled a couple of tunes from the repository to see what the calibration sets it at and
was surprised to see 0.0722 (13.85 afr) so engine is doing what it's told.

So question is why 13.85afr and not 14.7 afr ?

What's the implications for a emmissions test in a couple of years ?

(btw the na 6.4L calibrations calls for 14.53afr)

[guru1oftal]

Rams seem to run this as well in my experience. I assumed that the additional fuel provides a safety margin.
If it left the factory that way I would say that passing emissions shouldn't be an issue.

[1bh]

Looking through some of the engine data displays the other day, I noticed that at hot idle
AFR sits at ~13.7 which I thought was a bit weird as stoich for petrol is 14.7
I pulled a couple of tunes from the repository to see what the calibration sets it at and
was surprised to see 0.0722 (13.85 afr) so engine is doing what it's told.

So question is why 13.85afr and not 14.7 afr ?

What's the implications for a emmissions test in a couple of years ?

(btw the na 6.4L calibrations calls for 14.53afr)

The Afr shown is based on an e10-15 blend. If you install a wideband (14.7 cal) it would read correctly. Lambda is still 1

[rich24v]

After a datalog I can see the stock widebands report as I would expect.

afr.JPG

[fixit]

fwiw helcat is the same.. guessing dodge taking into account ethanol in gas