Ok let's swing back to this now that I've got some time
@fumanchu182 seems to really get it as the equation he posted is spot on for determining PE fueling. I built a spreadsheet to use for those to make things quick and easy.
Warning techie stuff below:
The stoich point is programmable in the Hellcat. Factory is .0722. Divide it by 1 to get AFR of 13.85 that is close to what is displayed on the dash. Mine usually reads like 13.5ish on pump 93 at idle and cruise. PE is power enrichment and there's a separate table that is an adder for when WOT is achieved. That's how you get the WOT fueling where you want. I bet the OP tune has a PE value of .0230 in that table (or there abouts) which would explain the 10.5 AFR reading on the dash. This assumes COT is turned off of course. That's pretty rich and too rich is just as almost as bad as too lean IMO. I believe rich tunes lead to burned up cats if still on the car. Factory PE table is .0110 which is 12.02 AFR, but they rely on COT which is yet another table with a fuel adder amount to come in pretty quick and you'll end up with a 10.5 or 10.8 or so AFR reading on the dash with pump gas when that happens.
Where
@AlleyCat missed the boat was trying to mix an E85 discussion at stoich in with a gasoline discussion at WOT. That's comparing apples and chalk. My point to him is that if his car is running E85 and he sees 10.9/11.1 on his AFR dash gauge at WOT then the factory stoich point for gasoline was not changed to stoich for E85. Doesn't mean his tune is wrong, but that's relevant for the OPs question.
To have the dash read the actual AFR on E85 the stoich point in the tune would need to be changed (with about a dozen other tables) to that of E85 as it has a different stoich point than gasoline. E85 is 9.85 (.1015) as Jonx96 posted above. Straight gasoline stoich is 14.7 (.0683) and SRT chose 13.85 (.0722) for whatever reason. Most think that is to account for the ethanol in most pump gasoline these days. Locally mine says "up to 10% ethanol". Once you get in to flex fuel tuning, you actually have multiple stoich points in the tune to account for varying percentages of ethanol and that gets pretty complex.
Do you have to change the stoich point in the tune to make the dash read correctly, no. Is it the right way to do it? I think so as I believe that is how the factory would have done it if they put the car out to run on E85. Cars will run just fine without making that change though, as long as the injector data is setup properly for the fuel being used, like around 25-30% more on the fuel mass for E85. Like I said before, I prefer to know what tune and fuel are in the car and making this change allows me to take a quick look at the dash and know. If I see 9.8x at idle I know I'm on E85, 13.x I'm on gasoline. My flex fuel tune works the exact same way E40 is around low 11, E60 low 10, etc (from memory).
All of that is talking AFR. If you're staying with a single fuel and know the stoich point and it never changes then dealing in AFR is fine. I did for YEARS on my old car. Once you start changing fuels with different stoich points it can get confusing so Lambda is a simpler way to think of it. Stoich for any fuel is Lambda 1. More than 1 is lean less than 1 is rich. HPTuners can read the wide bands in Lambda as well as some AFR settings for different fuels like gasoline, ethanol, LPG, etc, but you can't create a custom one like the Hellcat would need (13.85). Using Lambda is the easiest. For gasoline a Lambda of .82 - .83 is what I target for PE. .82 x 13.85 = 11.35 AFR. On E85 I target .81 Lambda .81 x 9.85 = 7.97. At WOT on my E85 tune my AFR gauge reads 7.97.
Clear as mud?
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