why can't the ecoboost truck run e85

 

Because reindeer don't fly

 

I don't think the turbos can handle the steam from that much ethanol in the fuel.

 

It's to hard on most parts!

 

Here is some info on e85, to be able to run e85 you would need larger injectors, fuel pump and a custom tune. People run e85 on turbo charged cars all the time and its not hard on the turbos and makes alot more power than pump gas.

It has more oxygen in it than gasoline, much more. This allows you to get more oxygen in the combustion chamber than you normally would. Even though this oxygen is bonded to the rest of the ethanol molecule before combustion, it's still burned in the cylinder, just like nitrous. The stoichiometric ratio of e85 is approximately 9.6:1 and gasoline's is approximately 14.7:1, so not only do you have more fuel to burn, but more oxygen, too! This is why most cars will make 15-20% more power on e85 than with even the highest octane race gasoline. (Chemically, the most power you could make would be 27% more than gasoline, but that's hard to reach due to other restrictions).

It reduces intake air temperatures four times more than gasoline when injected into the air fuel mixture at proper air-to-fuel ratios. This is because alcohol requires more energy to evaporate than gasoline does and you're also injecting about 35% more of it into the air fuel mixture than you are with gasoline. To prove this to yourself, imagine (or actually do it, safely!) dipping your fingers in gasoline and placing them in front of a fan. Your fingers would get pretty cold. Then imagine dipping your entire hand in alcohol and placing it in front of the same fan, it would get much, much colder.

e85 has an American octane rating of approximately 105, but the American test for octane rating (MON) uses a preheated air-fuel mixture at 300 degrees! This means that they inject e85 into the air and then heat that mixture to 300*F. This is why the commonly known octane rating of 105 is innacurate for e85. Preheating the air-fuel mixture doesn't accurately model intake temperatures that are so significantly lowered by e85 in real world applications. Because of the heat-lowering effectiveness of e85, it's more accurate octane rating is between 112 and 118. Because of this you can run higher compression, more boost, or both!

It burns faster than gasoline. At a 1:1 air fuel ratio, gasoline burns at 26cm/sec and ethanol burns at 41cm/sec. As you lean the air-to-fuel ratio, Ethanol continues to burn faster than gasoline. This is a major advantage over gasoline because it allows you to use more retarded ignition timing while still extracting maximum power out of the fuel. Retarded ignition timing is good because it allows you start the powerstroke later and harness the mechanical advantage the rod has on the crank as it's tilted rather than directly above crank. This also significantly reduces the shock the piston, rod and crank experience when the explosion happens before or during top dead center.

 

I thought advancing the timing was more beneficial to harnessing more energy than retarding it as what happens with bad gas or lower octane gas.

Advancing the timing of ignition allows earlier ignition of the mixture so that more of the cycle of the piston on ignition goes into burning the mixture thus more energy goes towards the turning of the the crankshaft.

Higher octane keeps the mixture from pre ignition so it doesn't burn before TDC thus you can advance the ignition timing more aggressively.

I could be wrong so please advise.

 

Not enough overhead in the injectors to meet ford criteria.

That said, e85 has been ran on the 3.5 2011-2014 models that were stock. If you turn up the boost with a tuner at all you will run out of fuel really quick which is dangerous. I don't suggest using more than e15 fuel as ford suggests on the 3.5 ecoboost.

 

Was referring to the other poster saying that e85 allows for cooler temp thus further retardation of ignition which is better for power. I thought the opposite were true. Cooler combustion allows for advanced timing and advanced timing allows more power.

 

My builder and tuner wants to run E85 on my truck but I was worried that something might give because I haven't seen anyone on it but thank you 4B11TX for the information. I will be doing a full bolt on tune E85 2.7EB

 

This is true, but it's more than the flame front is a little slower and more controlled/even combustion so it's safer.