Is it worth it?

[yrraljguthrie]

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.

 

[SniperDroid]

I get more mpg with 92 octane than 89.

 

[yrraljguthrie]

How much more mpg with the 92 octane?

 

[SniperDroid]

89 octane 8.4 measured. 92 octane 9.7 measured. Be advised, I choose the higher octane, not required for performance.

 

[yrraljguthrie]

You must have a lead foot! That's a 15% increase I think, so significant. Unless I've done the math wrong that would make $3.50 gasoline the same per mile as $3.00 87 octane. I may try that. Have to see what the 92 costs.

 

[SniperDroid]

Be advised, this is while towing an 8000 pound travel trailer. The primary use for the RAM is a tow vehicle

 

[mtofell]

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.

 

[mikeru]

For me the difference was negligible. 89 octane is 20 cents per gallon more than 87 where I fill up. I'm less concerned about fuel economy though than using what's recommended in the owner's manual so I go with 89.

 

[Dave Haddon]

Just did a trip from Saskatoon to Seattle. Warlock was loaded 3 dogs 2 humans and a full bed with mmm..600lbs of gear. Mostly cruise control 118km/hr..full fill on 89 and range was an incredible 1120. … when using 87.. range was 970…about even value overall on a long trip re diff in gas price but good for the hemi

 

[Mb7640]

I normally use 89 someone said to try 91 and i may see a increase in mpg so far nothing its the same but giving it a few more weeks. I get 16.5. I have never used 87 in a 5.7l i have had a bunch of them mostly challengers.