E15 fuel ok?

[jmissile]

Hi I've got a M56 and there's a gas station by me that's offering this now and it's way cheaper than the 93. Anyone try mixing a little of this gas with the 93? Scared to try but I heard that you can bump the octane up a point or 2 by blending the right amount of each. Cant find the true octane rating of the e15 but I feel like if it's cheaper and the car runs better on it or improves the mpg without hurting anything I'd like to start using it. Any thoughts?

[EdBwoy]

To summarize, after a lot of back and forth, vehicle manufacturers started acknowledging that E-15 wasn't too bad. That is after the EPA tested and declared it to be so around 2012. As a result, your 2011 owner's manual (as well as every one upto the 2017 model year), categorically claims neither E-15 nor E-85 should be used in your vehicle.
Your vehicle is not designed to run on them and their use can adversely affect the emissions system and could void your warranty.

However, in the 2018 owner's manual, the manual sort of backpedals on the E-15 issue.

• For the VQ37VHR it says fuels containing no more than 15% ethanol should be used. So E-15 should be ok, right?
• For the VK56VD, it explicitly says E-15 is verboten, like the older manuals said for all engines.

If it were my car, I'd play it conservative and stick to as little ethanol as possible, unleaded fuel, premium with an octane rating of 91 AKI (also called the [R+M]/2 method, which is what you'll see at most pumps at US gas stations). So, for me I'll fill with a minimum of 91 octane from the pump as I cannot guarantee what is in the lines as I try to mentally mix them.

[armybrat]

For the M56 it recommends 91 premium pure gas first and foremost, then if you use oxygenated fuel, no more than 10% ethanol. Most pumps around here in the Winston-Salem area are around 8%. If you're using a blender pump (one spout for all grades), it takes about 4 gallons of the premium 93 to dilute the E15 left in the hose down enough to be ok for use in your car. So using a gallon left in the hose as a constant, I'm guessing a 4 parts E10 to 1 part E15 would be ok for safe use. On a tank close to empty, (I think 16 gallons would be a close estimate) add 3 gallons of E15 first, them switch to 93 and top off with that. You'll flush the 1 gallon of E15 out which makes 4 total, then 12 gallons of 93 to blend it.

With that said...why? You're not really saving that much, as you're only buying 3 gallons of the E15, and you're only guessing at the correct ratio.

Honestly for a daily driver the 93 premium (or the 91) will be fine. You're cycling the fuel often enough to prevent build up associated with oxygenated fuels, which is more of an issue for engines that sit for an extended length of time, like a spare car or other gas powered items that don't run much and the fuel sits in the lines and tank. For those engines, I would use pure gas or add a stabilizer like Sta-Bil.

I choose to run 93 octane 100% pure gas (oxygenate free) - Yes it is more expensive, at $3.59/gal at Quality Mart here in Winston-Salem, NC but I get the maximum performance and MPG out of the engine so I gain some of the cost back.

From what I've been seeing on the news, looks like we're heading back to pure gas. Usually your smaller stations carry pure gas but now the bigger chains like Murphy's is now starting to carry it.

[Larz]

The only choices 90% of the fuel stations here are 83, 87, and 93. Very rare to find a station selling 91. There is a Race Trac station near me that is consistently about 20 cents cheaper than most. It's about 3 miles form the port where the fuel comes in. I fill there to save money rather than risking "E" type fuel or using low octane. It's often we here things like "if you can't afford the fuel, why did you buy this car?" That's rather harsh. There is nothing wrong with getting as much value as possible for each dollar spent. Just try to save smart instead of risky. When I travel, I won't buy fuel at ANY station that looks dirty, run-down, or one that has pumps that are damaged or dodgy looking. That's probably a bit picky on my part, but I don't allow price to be the only factor where I purchase fuel. I also avoid Shell stations who, in my experience, almost always have the highest prices. There is a Shell station in downtown Ft Lauderdale that charges almost 25 cents more than that the Mobil station just across the street!

[EdBwoy]

...That's probably a bit picky on my part, but I don't allow price to be the only factor where I purchase fuel...

You are not alone:
which-gas-stations-do-you-recommend-t620423.html