Why C7 stoich table adjusted to 14.1 but not gen V trucks ?!

[wesam]

Why C7 stoich table adjusted to 14.1 but not gen V trucks ?!
What if the fuel used in C7 has 0% ethanol ?

[ScarabEpic22]

My 2013 Sonic has the stoich point set to 14.1 as well. I think it's because the majority of fuel in the US has 10% ethanol these days (unfortunately). As to why the Vette has it set that way and trucks dont (assuming they're 14.7), that's really weird but chalk it up to a GM-ism.

[jrh]

Old thread but just saw this.

The non flex fuel trucks also target 14.1 for the entire table.

On the flex fuel trucks they don't set 0% to 14.1 and have a full AFR vs ethanol content "curve" because they have a flex fuel sensor so the 10%-12% ethanol content area (most pump fuel in the US now) has the correct AFR in it. If you happen to get 100% gasoline then it goes to the 0% location in the table.


Why C7 stoich table adjusted to 14.1 but not gen V trucks ?!
What if the fuel used in C7 has 0% ethanol ?

[PRAY]

So if one was doing a flex fuel tune in a 2016 Camaro then you should grab the flex curve from say a flex fuel truck and use that as a starting point? I have flex fuel on the car already but I am working through some stuff with going back and forth and different levels of E. I think I have narrowed it down to an injector offset table that has been causing the issues.

[jrh]

Yes, if you are converting an LT1 Camaro SS to Flex Fuel then you should copy the AFR vs ethanol content table from the trucks. The L83 trucks (5.3L) are the ones that are flex fuel but the L83 doesn't use the same injectors as the L86 (6.2L). The L86 and LT1 are basically identical other than oil pan, intake manifold and vacuum pump.

What injectors and fuel pump are you running to convert an LT1 to E85? Is this a stock LT1?


So if one was doing a flex fuel tune in a 2016 Camaro then you should grab the flex curve from say a flex fuel truck and use that as a starting point? I have flex fuel on the car already but I am working through some stuff with going back and forth and different levels of E. I think I have narrowed it down to an injector offset table that has been causing the issues.

[PRAY]

Yes, if you are converting an LT1 Camaro SS to Flex Fuel then you should copy the AFR vs ethanol content table from the trucks. The L83 trucks (5.3L) are the ones that are flex fuel but the L83 doesn't use the same injectors as the L86 (6.2L). The L86 and LT1 are basically identical other than oil pan, intake manifold and vacuum pump.

What injectors and fuel pump are you running to convert an LT1 to E85? Is this a stock LT1?

I have a 2014 Silverado with the flex 5.3L. I was looking at those tables and noticed the difference than what I used for my initial tunes.

The injector table I was referring to is B1617 Injector Flow Rate E85 Modifier. I set that to 1 and it seems to have really helped my issues.

I am still running the stock pump and injectors. The car has made 462/480rw with the stock exhaust and has run 11.07@123 at full weight with just my ported IM/TB, CAI, E85, tune on the stock converter. I have since added headers and on pump gas they were worth as much as 24/20rw. I am back on E now and I am finishing up my tune. I am looking to be the first in the 10's with just boltons on Saturday. I will be porting the heads and running a small stock converter cam next. I am looking to go sub 10.50's like that. I will then install the LT4 blower I have had sitting on the shelf for 6 months and shoot for 9's on pump. I will have to do the ZL1 in tank and LT4 high side to run E or do any more than 600rw.