Don't hesitate. 87 runs fine in my 2014. No ping at all. I also had an 06 and it ran fine on 87

 

Even though I use 89 I do agree with "old man". I have never experienced pinging with 87 octane in either of my hemis. I used 87 pretty well exclusively in the 03 (first gen hemi) with no obvious issues whatsoever...except that it drank gas like it was water!
There are some on DF however who would contend that even though you can't hear it, there may be pre-detonation happening when using 87 octane. I have even read on here that people have re-built these engines and supposedly the ones ran strictly on 87 octane had more signs of wear than those ran on 89. From my experience, I don't think you will have any trouble with 87 octane.

 

If anything, maybe ill save using 87 for when i'm topping off with still at least half a tank of 89. For a 12c per gallon difference it's not something i'm losing sleep over. But ill give it a shot.

 

Here I am a newby Canadian who is considering the purchase of a 2012 Ram 2500 Crew Cab 4WD with the 5.7 Hemi engine. From the posts above, it appears that 87 octane fuel will be OK. What kind of fuel efficiency could I expect with this engine running at highway speeds under no towing conditions? I realize the 2500 is heavier than most of your 1500 users, but I'd like just some estimates.

 

Depending on the terrain of course, I think you could legitimately expect to get 16 to 18 mpg (US) on the highway, perhaps more under the right conditions. Not sure how much of a weight difference with the 2500 frame so maybe 1 mpg less. I drive under mostly hilly conditions usually with a headwind of at least 30 kph so my numbers are skewed a little lower than someone who drives say on the prairies where I would expect significant gains in mpg over what I am getting.

 

Glenn....if Canada requires at least 5%, why do you say premium has 0. I mean your math adds up but the intent sure doesn't. It makes no sense to me to dump all the ethanol in just two blends...then claim to have at least 5% added to all gasoline, and what is your reasoning behind better mileage with 89 over 87. I have never seen any difference of mpg between the two. This is confusing to me.

 

the fact is that all "pure gasoline" gallons contain the same energy. 87 and 89 have the same energy content. I've not noticed any difference in MPG with the 87 vs the 89. Some will say that the hemi gets de-tuned when running the 87, but that is only the case when pre-detonation is sensed, and under normal driving, that is rare.

Ethanol has a lower energy content that gasoline, so a 5% blend has less energy than pure gas but more than a 10%.

 

Finding information on the use of ethanol in our gas has not been easy. It is true that the Canadian government has mandated a minimum of 5% ethanol in the majority of provinces in Canada. It is also true that many gas stations here advertise that their gas may contain up to 10% ethanol. Where it gets a little confusing is that (from the information that I could find) 91 octane gasoline may or may not contain any ethanol at all. I have also read statements issued by various government agencies requesting that only supreme (91 octane and up) gasoline be used in small engines due to the potential for damage to the equipment when using ethanol-blended fuel but I have no idea if this true so please don't ask me to explain why this would be the case. I can only go by what I have seen, read and experienced. If someone has any other information on this I would be very interested to hear.

Now as far as the 87/89 octane debate goes, I have experienced a relatively small increase in my fuel economy when using 89 instead of 87. I've noticed it too many times for me to believe otherwise.

 

Thanks glenn.d. This will at least give me some indication of what I could expect. Likely mileage would be 19 to 21 mpg using out Canadian Imperial gallon - but also quite higher priced than yours. So, I think even with 18-20 mpg, I'd be OK with that and should be able to estimate my operating cost on a change of trucks from diesel to gas.

 

If as you say, the 87 has 10% ethanol and the 89 has 5%, then that the reason you see a difference in MPGs, It is not the octane rating.