Is the extra .20 to .30 cents a gallon worth the MPG increase compared to 87 octane fuel

 

IMO, No.

 

What mpg increase??? All other things being the same, it won't add anything, and maybe make it worse.

 

Higher octane fuel does not contain more energy, it's just harder to burn. This allows it to be used in higher compression engines that can get better compression ratios which WILL result in high power.

Unless your engine is a high-compression model, premium fuel normally offers no performance benefit.

If your engine is equipped with a knock sensor and you are going to be towing in hilly or mountainous areas, moving to a higher octane fuel may help maintain engine power by keeping the pre-ignition down during heavy load events (like full throttle going up a big hill), thus keeping the knock sensor's readings from pulling timing. This is the only time I ever purchase 89 or higher fuel.

 

If you want to run 93 octane you should have a tune for 93 octane fuel. On a stock truck or 87 tune 93 octane fuel will not do anything mpg or power wise unless you are experiencing major detonation with 87. But if your getting detonation on 87 you have other issues that need addressing.

 

Little known fact: Running higher octane fuel than required by the engine will actually hurt performance and mpg (by a tiny amount). The higher the octane, the slower it burns. The slower it burns, the slower the cylinder pressure builds so the less work it performs.

That being said, if the engine requires higher octane, it will hurt the mpg to use lower octane. The knock sensor will pull ignition advance out to keep it from knocking, but that lowers efficiency.

So for best results, start with the exact octane recommended. If bone stock, that is 87.

As dkf mentioned, if engine has been modified (like with more ignition advance in a tuner), then you need to go with the right fuel for the modifications.

After that, if you are able to hear/feel knocking, you can use it to fine tune.

If you hear a touch of knocking every now and then (like 1 or 2 seconds), that indicates the PCM is trying to put in more advance, but then senses knocking and pulls it back out Try one grade higher.

If you never hear knocking, you're either spot on or using better than needed. You could try using one grade lower.

In my truck, I have higher than stock compression and more advance due to the tune. I've found I need 91 in summer and 89 in winter.

 

I've had this conversation more times than I can remember. Most people have no idea what that octane rating means. I know several people who waste their money with higher than recommended octane fuels and firmly believe they are seeing benefits.

The higher the octane rating, the more resistant to compression detonation the fuel is. The engine has to be designed to run on higher octane fuels to get the benefit from it. Preventing pre-ignition during compression is the only benefit.

 

I've even heard of folks giving their stock 87 autos premium fuel occasionally as a 'special treat' if you can believe that. It's a machine, for crissakes!

 

I run 93 octane, but I have a tune. (It rips!!!!!!) I bought a v10 so i'm not too concerned with gas milage. .20 cents times 38 gallons fill up. = $7.60 per tank more per fill up. not that big a deal on a $130 fill up. Just my two cents

 

Run fuel that has no Ethanol in it and you will get better miliage. Ethanol is a lose lose senario for the consumer and the enviroment and our dependence on oil. Octane should not be an issue on a stock V10 with low compression. Octane is there to suppress knock. Now if you had a turbo on that V10, 93 octane would be a smart move.

Perry

 

My 2010 picked up .6mpg while towing using 93 so doing the math it still = NO. It's not worth the $$.

I tried it several times going to and from the race track hauling my toy hauler with the race car in the back. Same results. Stick with 87 until it out of warranty then 5 star tune it and recheck.

44

 

One caveat to what I said earlier though...

I DID pick up an increase in pure stop-and-go/around-town mileage using 93 octane AND a performance tune from Mike@5-star. I went from 5-5.5MPGs on the stock tune, to 6.5MPGs on his 93 octane performance tune. At the time, 93 octane was about 10% more in price. Now, it's down to almost 5% difference. From 5.5 to 6.5MPGs was an 18% increase, so it DID save me $'s.

However, that's in my particular case, the fact that I can't keep my foot out of it, and that it was pure stop-and-go. As you can tell from the horrible gas mileage in the first place

 

How about if there is less ethanol in the higher octane mix.

Here locally in Canada 87 octane has 10% ethanol. 5% for mid grade and 0% for high grade (high octane).

If I were to spend a little more for less ethanol does that make a difference?

08 V10 F350 crew cab short box will be towing a 6500 lb trailer in the rockies this summer.

 

I think there is a darned good chance it would make enough difference! I would certainly be giving it a try.

 

It might, it's worth a try. Even better would be a custom tune to take advantage of the higher octane plus zero ethanol