Is it worth it?

[yrraljguthrie]

Well, I've done the math. I've found that in this and other situations, "I doubt it and I think so" don't do me a lot of good.

 

[Zac1]

Rear end - 321 gets better millage than 392. With that being said my 2022 4x4 with 392 got better millage with Costco 91 non-ethanol. However Costco stop offering non-ethanol. Now I am using 88 non-ethanol. I am not sure yet this is my first tank. I am around 15.2 in the city. As someone said ethanol has no business being add to gasoline except subsidizing corn farmers.

 

[craigsez]

Unless tuned for a octane then its damn near pointless

 

[yrraljguthrie]

"Unless tuned for an octane then its damn near pointless"

I believe the 5.7 and most modern engines can adjust tuning depending on how the engine is reacting. From what I've read(yea...on the internet) engines tuned for 89 octane run just fine on 87, although with slightly less performance.

 

[Bandit1859]

There's some payback calculation on 89 v. 87 octane and I can't remember exactly what it is. I'm thinking it's around 15 cents. Basically, if you have to pay more than 15 cents it's not worth it. Years ago there was a long thread about this and some chemical/fuel engineer had it all calculated out. Of course, this is all predicated on the fact that the engine is tuned/capable of using the higher octane which I believe these modern Rams are.

I had a longstanding argument with my dad about this. He swore up and down that putting 92 octane gas into his 1991 Toyota Camry was why the car lasted to nearly 300K miles. That engine wouldn't know the difference in the octane and he was ******* away my inheritance It lasted to 300K miles because it was a Toyota.

Once a year I camp out in the sticks and the only gas available is ethanol-free 92 and my truck LOVES that stuff. I'm thinking I get 5-10% better mileage but that's because it has no ethanol.

The same engineer I cited above laughed about the whole ethanol in fuel thing and said after years in the industry the only reason he could figure we put 10% ethanol in the fuel is to keep the corn farmers in business. It causes autos to get 10% worse fuel mileage so it's kind of a wash.

Also using premium generally means higher quality fuel. Octane really don’t mater but better quality formula

 

[mtofell]

Also using premium generally means higher quality fuel.

This is the million dollar question.... is it really? In what way? People that seem to know have always told me there is absolutely no difference other than octane. Not that we'd ever know, I suppose.

 

[yrraljguthrie]

Well, the amount of energy in gasoline does not change between octanes. So in that way, it doesn't matter. However the flash point changes or when it ignites in the cylinder changes. So if the timing of the engine is set to better utilize one octane or the other it does matter in that way. However (again) most or all of today's engines are computer controlled and can change the timing on the fly. So maybe it doesn't matter. However(again) the more variables there are the bigger the likelihood is that it does matter.

 

[Rayzaa]

I recently filled a half-empty tank with 89 octane. 87 was in it. Both had ethanol. With that mix, I've noticed at least a .6 mpg increase. Or course that's only on the one fill-up, but it coincides closely with previous instances with my previous F-150. The fill was at the same pump and I'm driving the same roads. This will pay for about 1/2 of the increase in the price of the 89 vs. 87 octane. I intend to try to use this fill-up and then see what mostly 89 octane by itself will do. Has anyone else noticed an increase in mpg using 89 octane or perhaps 87 or 89 without ethanol? I'm beginning to think using 89 octane will increase the mpg enough to pay the difference in price.

I haven't noticed an increase in MPG using 89. I haven't tried 89 with no ethanol yet. There only one station around here that has it and it's about .15 cents per gallon more.

 

[Jane S]

Also using premium generally means higher quality fuel. Octane really don’t mater but better quality formula

WHAT!!!!!!!!!!!!!!!!!!!!!!!!!

All premium is is higher octaine.

 

[yrraljguthrie]

"All premium is is higher octane. "

That's a little misleading as I just bought some 87-octane ethanol-free gasoline. Some would call that premium.

 

[shagya]

Maybe not relevant in this discussion but eventually interesting as info because
we only have 95 octan with 10% E (what I use) and 100 octan with 5% E in Hungary. My Gen4 Rebel MY 2016 has 14,7 mpg running on 35" tires mostly short distances (50-100 miles) over countryside, up and downhill. Carefully towing my horsetrailer 13-13,4 mpg. Highway only 5% max.80 mls/h.
So I can not compare with lower octan fuel.

 

[Wire4money]

Maybe not relevant in this discussion but eventually interesting as info because
we only have 95 octan with 10% E (what I use) and 100 octan with 5% E in Hungary. My Gen4 Rebel MY 2016 has 14,7 mpg running on 35" tires mostly short distances (50-100 miles) over countryside, up and downhill. Carefully towing my horsetrailer 13-13,4 mpg. Highway only 5% max.80 mls/h.
So I can not compare with lower octan fuel.

Your octane is calculated differently than it is in the states. I would imagine your 95 is equivalent to our 87.

 

[Docwagon1776]

Your octane is calculated differently than it is in the states. I would imagine your 95 is equivalent to our 87.

Euro 95 is US 91.

 

[shagya]

Euro 95 is US 91.

OK, - thanks for this info ! I didn't know that.