on na motors i know 12.8 to 13.1 is ideal for max power but with fuel having 10 percent ethanol in it now so should the numbers change?
Correct.okay cool.. didnt know it worked like that.. so 13.0 a/f on gas is like 12.54 a/f on e10 right? 13/14.64= .8879 12.54/14.1= 889
Yes. You would normally want the stoich in the tune set to he fuel you are running.Kevin, Shouldn't you at least change the base fuel stoich scalar in the tune to the actual stoich of the fuel burned.
Won't the ECM still think 14.64 is the stoich of the fuel even though it's 14.1 with E10 and give you a slightly false reading from what is truely happening with the A/F ratio?
Example: Base tune has fuel stoich scalar at 14.64. Thus when you tune for lambda at all levels it will be "right on" for NON E10 regualr unleaded.
But, for E10 you should set the base fuel stoich scalar to 14.1 making a true A/F ratio that's more accurate for the lambda tables to read from.
If you have the scalar for stoich set at 14.64 and the fuel burned is at 14.1 stoich, then you're not getting the true commanded lambda in the tune correct?
Sorry to highjack thead OP.
I'm sure it is set to gasoline. I did on my E85 car just so I didn't have to change the gauge. I tuned for 11.7 on E85, wideband set to gasoline which is about 7.7 on an E85 wideband. .79918 Lambda. Or basically 20% rich.would it be a dumb question to ask the tuner what his wide band is set at? i know california has had e10 for awhile but i believe tuners are still sticking to the 14.7 rule..
I'm sure it is set to gasoline. I did on my E85 car just so I didn't have to change the gauge. I tuned for 11.7 on E85, wideband set to gasoline which is about 7.7 on an E85 wideband. .79918 Lambda. Or basically 20% rich.
omg so my 12.6 tune is more like a 12.1 tune?? what the french? gas in california is all e10. why dont the tuners pick up on this?
Because most tuners arent mathmeticians or chemists.
10% ethanol mix, in the grand scheme of things, doesnt look (to the everyday person) like its a necessity to fine tune and adjust values for, as opposed to E85, which combusts nothing like standard gasoline.
although that is an incorrect mentality, in my opinion...
i dont know how i will be able to talk a local tuner into setting the a/f to 13.1-2 on a 14.7 stoich to get 12.7 ish on e10 omg.. these people already think im crazy from asking questions..
omg so my 12.6 tune is more like a 12.1 tune?? what the french? gas in california is all e10. why dont the tuners pick up on this?
i dont know how i will be able to talk a local tuner into setting the a/f to 13.1-2 on a 14.7 stoich to get 12.7 ish on e10 omg.. these people already think im crazy from asking questions..
Yes. You would normally want the stoich in the tune set to he fuel you are running.
Although I have found there to be less fuel spikes with returnless systems leaving stoich @ 14.64 and rescaling the injector slopes and engine displacement accordingly. I have tried it both ways and it seems to work better for some reason. :shrug:
Again your missing the mathmatics here.
Example: NON E10 stoich is 14.7 and true E10 stoich is 14.1
Now if you tune according to a wideband set to gasoline stoich of 14.7 and your running E10 in the tank then the following mathmatics need to be applied.
E10 stoich ratio/gasoline stoich ratio X Gasoline max power air fual ratio = E10 max power air fuel ratio.
14.1/14.7*12.6=12.09 So 12.09 is the power side of E10 which reads 12.6 on a gasoline calibrated(nonE10) wideband. QUOTE setting the a/f to 13.1-2 on a 14.7 stoich to get 12.7 ish on e10 QUOTE as you say is not the power side for E10 to be tuning to. It is 12.09 at Wide open Throttle. An air fuel ratio of 12.5-12.6 is the power side of non ethanol regular unleaded gasoline ONLY.
So on a wideband set to gasoline(non E10) stoich you still need to tune to the SAME gasoline's power side as well. To figure out what is truely coming out of the tail pipe you need to apply the above formula.
If you have your tuner set your E10 fueled engine tune to read 13.1 at WOT on a gasoline calibrated wideband then you'll end up running lean and buying new pistons.
Yes. But only on returnless systems.Interesting point. I never even thought of that.
Is that true even on the E85 side as well, leaving 14.64 as the stoich scalar and tuning from there?
Again your missing the mathmatics here.
Example: NON E10 stoich is 14.7 and true E10 stoich is 14.1
Now if you tune according to a wideband set to gasoline stoich of 14.7 and your running E10 in the tank then the following mathmatics need to be applied.
E10 stoich ratio/gasoline stoich ratio X Gasoline max power air fual ratio = E10 max power air fuel ratio.
14.1/14.7*12.6=12.09 So 12.09 is the power side of E10 which reads 12.6 on a gasoline calibrated(nonE10) wideband. QUOTE setting the a/f to 13.1-2 on a 14.7 stoich to get 12.7 ish on e10 QUOTE as you say is not the power side for E10 to be tuning to. It is 12.09 at Wide open Throttle. An air fuel ratio of 12.5-12.6 is the power side of non ethanol regular unleaded gasoline ONLY.
So on a wideband set to gasoline(non E10) stoich you still need to tune to the SAME gasoline's power side as well. To figure out what is truely coming out of the tail pipe you need to apply the above formula.
If you have your tuner set your E10 fueled engine tune to read 13.1 at WOT on a gasoline calibrated wideband then you'll end up running lean and buying new pistons.
how did you get that 12.6 is ideal for pure gas? also with that math we are just getting a conversion from one fuel to another.. what is the ideal lambda for e10? i have read for fossil fuels .9 lamda makes the most power.. so that would put e10 at 12.7?