Ok, educate me. How does the definition of AKI change when using ethanol?
Are you asking me to Google that for you? Because my vast experience in blended fuels and tuning fords apparently isnāt cutting it. You can google all that you need to support your position but I assure you Iāve blended, tuned and raced current gen ford vehicles in just about any octane or density altitude scenario you could come up with. I have hundreds and hundreds of log files from many ford vehicles seeing the extent of how the stock computer handles blended fuels itās both tuned and not tuned for. I made a complete video on how coyote engines learn flex fuel from e10-e77. Iāll share that with you if you like.
Pretty sure he was sincerely asking for education. Iām watching along as Iām also interested. And I agree with both of you that the OP using ethanol free on his turbocharged Bronco is wasting money and possibly not seeing full power potential that ethanol brings to the table. I know zero about the knock reduction of either though and assumed octane was octane.
No, I am not asking you to Google anything. Also, I assure you that I have hundreds of hours dyno tuning and logging forced induction setups (as I used to own my own dyno shop). My tuning has resulted in national championship wins in import classes and SCCA racing. That said, my knowledge base is 20 years old and times change.
I mean lets just google that for you then. Took 5ish seconds. Truth is, adding the ethanol will always increase effective octane based on simple preignition resistance. If you see spark knock with 88 e0, depending on how bad you might not see the same spark knock on e10 87. And if you blend up to say e20 87. Thats adding the appropriate measure of E85 to a tank of e10 87 to bump the blend to e20, you will 1000% have more spark knock prevention/protection. Push that to e30 and so on and the effective octane goes up with it. E20 87 is like 89/90 effective octane. Just like E70+ pushed effective octane well over 100. 102-105ish. This is super simple stuff that you as a professional calibrator should know. E85 when taking to the limit might require a much higher fuel volume demand, but compared to similar octane gas like 110, its pennies to pounds better cost to performance wise. Until you get to the limit of E85.
Thanks, but that makes octane a meaningless measurement then. Regardless of blend, the knock resistance of a fuel "should be" consistent. In other words 93 octane E0 "should" have the same knock resistance as 93 octane E10.I mean lets just google that for you then. Took 5ish seconds. Truth is, adding the ethanol will always increase effective octane based on simple preignition resistance. If you see spark knock with 88 e0, depending on how bad you might not see the same spark knock on e10 87. And if you blend up to say e20 87. Thats adding the appropriate measure of E85 to a tank of e10 87 to bump the blend to e20, you will 1000% have more spark knock prevention/protection. Push that to e30 and so on and the effective octane goes up with it. E20 87 is like 89/90 effective octane. Just like E70+ pushed effective octane well over 100. 102-105ish. This is super simple stuff that you as a professional calibrator should know. E85 when taking to the limit might require a much higher fuel volume demand, but compared to similar octane gas like 110, its pennies to pounds better cost to performance wise. Until you get to the limit of E85.
In closing, Ford has calibrated this and many other factory vehicles to run on e10 pump gas. If you run e free gas, you are then relying on fuel trims to continually remove fuel added to maintain stoich. Lets hope a wideband doesnt degrade or go bad which will likely result in a rich condition and engine light along with horrible gas mileage and poor performance. Plus the wasted money spent on e free gas that not only isnt doing anything for mileage or performance, but is also not helping nor hurting the fuel system in any way.
What you should be doing is running 93 e10. This will give you the greatest "pump gas" knock protection as well as give you the most spark you're going to get on that fuel from the factory calibration. And on the chance you will need MAX power and tq, you should add in around 2 gallons of quality E85 then top off with 93 for an effective e20 blend or about 94/95 octane. That should top out what ford allows for spark added in the absence of knock, and will get you all the power your bronco should be capable of making. The vehicle is more than capable of adding a bit of fuel via the fuel trims to offset for the higher fuel volume demand, but you will also get a big octane bump from it without spending a shiteload on race fuel.
In theory this would be correct but in actual practice itās not. Iāve seen the effects of running e free 90 vs 87 and 91. Specifically here in my use case, the e free fuel always made less power while picking up knock first. And remember again your stoich is 14.08. E free would be 14.70. So leaving the ford stoich value would mean you are over fueling and then having to pull full out via fuel trims to compensate and keep stoich. You seeing better gas mileage is a complete contradiction to what should be happening.
The Bronco running in closed loop is going to pull fuel to make the lamda sensor happy regardless of the fuel. E10 requires more fuel to hit the target lamda number (although it may be represented at 14.08:1 ratio in software, that's not how a wideband O2 works really). The stoichiometric lamda is essentially the same for gasoline, e10 gasoline, E85, and E100 but the amount of fuel to get there is not.
