Sorry if this has been covered already, but I am strongly considering the Ecoboost for my next motor. My question is, living in Minnesota we have 87 octane (10% ethanol), 89 octane (10% ethanol)and 91 or 92 octane with no ethanol. We also have E85 readily available where I live, near Fargo ND. I just read an article in the Minneapolis Star Tribune that said the EPA is pushing to get 15% ethanol in most gas. I believe you CANNOT run E85 in the Ecoboost, but will even 10-15% ethanol screw with this motor??

 

I bet 10% will be ok. 15%, I'm not too sure.

 

I believe the owner's manuals are up on the motorcraft site for the 2011s. Maybe they have one for the Ecoboost that tells you.

 

In brochure it says E85 ok for 3.7 & 5.0, but not for EB or 6.2L. No further breakdown past that.

My bet is 15% will be fine for all new engines 07+.

 

Their website specs say regular unleaded.
Also they say horsepower and torque figures were achieved with regular unleaded.
Al

 

The online owners manual says it was designed to run on 87 octane but you will notice reduced performance in hot weather or while towing unless 91+ octane is used. I'm going to take that to mean that 87 is OK for most driving conditions.