Premium fuel with the 2.7?

I've read some posts that some owners claim that they get better mpg using premium fuel. I am wondering if it's safe to run 93 octane or even mid grade in my 2016 2.7? This is my first 2.7 and I am still learning everyday. Any feedback with experiences with higher octane fuel is greatly appreciated.

Thanks guys

 

You will probably get better mileage. You are safe running any fuel it's not more aggressive fuel with higher octane numbers it's actually more stable fuel which is why you need it for a high compression engine. Keep in mind you won't see any real MPG benefits for the first few tanks as your ECU has to learn the new curve as the fuel will not behave like the 87 octane you had in it previously. I'd also start with 91 before moving up to something like 93, I dunno how common 93 is in Florida?

Don't spend more than a few extra dollars per tank. You will eat up the fuel savings if you do. Around here it's ~$0.20 more per gallon and that's doable for my 4L when it comes to feel and better efficiency.

 

93 is VERY common in FL, even up in Kansas where I'm living now for the next few months. I think I'm going to give it a shot. Also, I don't live near good "top tier" gas stations like Shell, Mobil, BP, etc. Mostly all Phillips 66 gas, which I have no idea if it's clean?

 

Thanks Denny for your input!

 

Can't comment on that, in California you can nearly trip over everything from Chevron-priced gas to shitty half-water-Arco

Like I said it's just more stable fuel so the motor will have to learn the new curves of the fuel before it feels right. I switched to 91 awhile back and run nothing but in my 4L.

 

I switched over to ethenol free 91. Not sure about mpgs, and did not gain any crazy power, but i did notice it seems to be smoother at idle and when lugging the engine. Went through cades cove yesterday and at 5 mph going up the hills it seemed to be a little more smooth.

 

The 4.0 v6 is designed to take advantage of higher octane fuels, it says so in the owner's manual. The 2.7 does not have this benefit, so I don't bother with anything over the recommended 87 octane.

The consensus here on TW, and with many experienced mechanics and technicians, is that the 2.7 will not realize any significant power gain or increased MPG using higher octane fuel, but you will get better MPG by switching to ethanol-free of the same octane.

 

and ethanol-free fuel is difficult to find for me

 

Higher octane fuel is a great way to compensate for that, contrary to his statement (and many you see around here) I find first hand experience running 91+ octane fuel is a good way to see how it actually affects your motor. If you listen to most people around here even the 4L sees no benefit from 91+.

 

I'm going to give it a try for a few tanks and see how it runs, I also have a calibrated scanguage that I find to be very accurate to hand calculation.

 

I ran high octane in my 2008 2.7 for a few tanks and I didn't noticed a single difference except a lighter wallet. Your experience may be different, so I say give it a try. It won't hurt anything.

 

It's your money.

 

Today's 87-93 spread at the Clearwater Costco, a top tier station, is .43 per/gal.

Meaning if you average 20mpg now, break even would be 23.9mpg.

I'm with @ naac3taco on this one. Betting net loss, not even break even.

 

Right now I'm averaging 23mpg to a tank consistently. $2.12 for regular and $2.42 for 93 octane locally.

 

26.1 mpg would be your break even

 

I am lucky and have pretty easy access to corn free gas. I had boosted cars in my past and got used to buying premium. I will buy it and spend the money just because I like my truck, and right or wrong I feel like it is better for it in the long run. Even if I do not see a return on my investment.

 

Doesn't running higher octane fuel than you need cause more soot and carbon deposits because it burns slower?

 

Doesn't do anything.
I ran it in my 2nd gen 4.0 and the mileage was the same.

 

No. It doesnt burn slower. Gas is gas. Octane is easy to understand and yet is massively misunderstood. People see nhra cars using 8 billion octane, a d equate that as 8 billion octane makes their civic a dragster.

The following isnt true but the concept is.

octane is basically a measurement of how much heat is required to make the fuel ignite. The higher the octane, the more heat needed. Low compression engines generate low heat during the compression stroke, so low octane is needed. Higher octane LIKELY won't hurt anything (read the BUT below)

High compression engines generate more heat during compression. If the octane is to low, the heat generated prior to the ignition system creating spark could set of the fuel charge, giving you pre-ignition/detonation/pinging/dieseling. 4 words same thing. That can damage the engine. So higher octane must be used.

The energy content in the fuel is identical, only how much energy is needed to release the fuels energy changes. If your engine produces all the power it can on low octane it will see 0 benefit from going higher. You'll just be spending more money for the same results.

Likewise high octane isn't 'better' for your engine. It's the same from grade to grade of the same company.

A. TON of money has been spent figuring out what octane is needed for your engine to make max power safely. The minimum octane required for that to happen has a buffer built in. Going higher won't gain a thing, physics says no and physics is right.


Here are the buts.

Modern cars don't have static timing, if you put a low octane fuel in that causes detonation, it will back of the timing to keep damage from happening. So you can run low in most cards that require high. No damage you just limit the engine a bit. If the timing is r etarded, the max power available will also drop. If you actually knew how much power you use from moment to moment while driving, you would probably be happy saving a few bucks ever full up. Unless you're full throttle all the time you're engine is getting along with 30hp most of the time, even if it peaks at 5000000000000000.

You CANT do this on a boosted engine. High octane only.

And studies on low compression engines, especially with not fantastic ignition systems show that running high octane produces lower power. If the engine can't reliably ignite the fuel charge you lose power.

And octane requirements are variable. Increase altitude, you decrease needed octane.

 

I tried one tank of 91 octane this summer and my fuel economy dropped to 21 mpg. The only other tank that I got mpg that low was in the winter on crapanol gas. To be fair, I was running the A/C, but every other tank in the last 12,000 miles has been more than this, so no more high octane for me. My engine is the dual VVTi.

I was told in an automotive engineering class in college that high octane gasoline has a slower flame propagation than a lower octane gasoline, so it does burn slower. Detonation is when, as the flame front is moving away from the spark plug, at some point, the rest of the unburned mixture ignites simultaneously causing a pinging sound as heard outside the motor. "Pinging" and detonation are the same thing.

Pre-ignition is when the mixture is ignited before the spark plugs fires. This can be caused by compression and/or a hot spot (usually glowing carbon) in the combustion chamber. Detonation is bad for an engine. Pre-ignition can destroy an engine.