Stoich is 24.23?

Whats up with this tune that the tuner set stoich to 24.23? Its a turbo 6.0, no blow off valve or intercooler. Also... seeing 84kpa at idle and what would seem like low idle timing?

I've read a few times there is a lazy way to tune AFR but not experienced enough to know where they are making up for this 24.23 commanded AFR?

Is the lack of BOV causing higher than normal KPA at idle? Attachment 103539Attachment 103540

Also, he was told to run only E85 and the sensor is disabled. This tune did make 516 to the tire before it ran out of pump.

That’s 12.1 halfed, still not correct for e85.. didn’t look at tune but most gen 3 ECMs have a 25x lb limit on the injector so no need to double stoich/half IFR..

Unless you have a fairly large duration cam, I bet it’s a vac leak

Your iac is completely closed because it is trying to lower the idle speed and it is also removing timing to try to get it down. You could open the throttle blade some or drill a little hole in the blade.

Is the tune scaled to get more spark table?

9.7 stoich times 2.5 = 24.25 ( ECU corrects to 24.23)

36.3 lb/hr injector flow rate times 2.5 = 90.1 lb/hr

Airmass from VE % stays the same, But you can get to 2.5 times the airmass on the same axis scale. Its like cutting things by multiplying by .4, just inverse way of doing it on the ratio.


Air/ Fuel = Stoich

(Air *.4)/(Fuel *.4)= Stoich

Air = Fuel * Stoich

Air = (2.5* Fuel) * (2.5 * Stoich)

Air/ Stoich= Fuel

(.4* Air)/(.4 *Stoich)= Fuel

Thanks - dumb question perhaps.... What the reason for doing it this way if they also did the 3 bar OS?

Best thing to do would have been leave AFR commanded to normal value of e85 (rarely it’s 9.8 unless from a barrel) I would use low 10s as stoich)

Half IFR double stoich does nothing for cylinder air mass which control spark...

Scaled tuned would have been best thing to do here! Even with 3 bar OS still stuck with low cylinder air mass limit

Its not half IFR and double stoich, its 2.5 times both.

It does keep cylinder airmass near NA levels just look at the math above. Also If you look at the VE table in the tune posted its not much over 100% even in the higher MAP values. At 15-20 lbs of boost, in reality, it would be over 150% and much closer to 200% or even higher closer to 30lb of boost, well over the 1.2g cylinder airmass limit. With this tune cylinder airmass probably stays around 1.1g cylinder airmass, until above 22.5 pounds of boost.