2017 ignition orange ram

2017 Ram 1500 owners debate the best fuel octane for their trucks

Ram recommends using 87 or 89 octane for the new 2017 Ram 1500. Owners talk about their real world experience.
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We all know that the automakers vary on what they recommend for fuel for your everyday driver. A 2017 Ram 1500 owner reached out to members of a popular Ram forum to find out what works best in the real world. Hayden from Idaho asks “I just brought the new truck home yesterday. I have a new 2017 RAM 5.7L Hemi on a 2017 1500 Crew Cab with 6'4" bed. When looking through the 2017 User Guide (owner's manual), specifically the Maintaining Your Vehicle > Fluids / Lubricants section, it says for this engine: "89 octane recommended, 87 octane acceptable, 0-15% ethanol". What are you all running? Do you notice a performance difference using 89 vs 87? MPG difference? Any other thoughts?”

Engines aren’t programmed for high octane

Thunder, from North Carolina, was the first to reach out. He apparently isn’t a fan of ethanol. “I found a place nearby that sells ethanol free 89 so I run that. That is more because its ethanol free than because its 89 though.” Thunder goes on to explain that the higher octane doesn’t necessarily help because the trucks aren’t programmed to make the best use of it. “Your truck can't detect fuel octane, all it can do is vary timing somewhat. It cannot advance timing enough to take advantage of any octane higher than 89. Octane is a measure of resistance to detonation so higher octane fuel actually has less energy in a given quantity. If your engine cannot advance timing far enough to take advantage of higher octane, or does not have a high enough compression ratio to need it you are wasting money on fuel that will get you worse mileage and may leave more deposits in your engine.”

Paramedic, from Pennsylvania, writes, “I always run 89 and occasionally throw a tank of 93 in there (Sunoco). I definitely get way better fuel mileage running 93 on long trips.”

Much like Thunder, Monster has a clear understanding of what the fuel can and can’t do for these engines. He obviously worked in the business. “We all know engines run much more efficient when cold dry air is ingested, humid hot air reduces efficiency and cause timing to be pulled back. Higher octane helps reduce the amount of timing pulled but I contended only laboratory equipment could really measure the difference in engine performance. I believe optimum performance is defined as the least amount of timing pull back in the worst of climates the Hemi may be operated in. The compression level of the engine in a hot wet climate likely dictates 89 octane for the best engine efficiency. 93 octane is likely too much for the Hemi and probably reduces the efficiency of the engine due to the difficulty of fuel detonation in the lower compression engine at the time of the peak power stroke. When I was at GM Powertrain, optimum performance was defined as emissions compliant, reduced warranty costs, and customer satisfaction, in this order.”

Fishing has a similar take on the question. He also tries to avoid ethanol. “I run 89. The average price difference between 87 and 89 is $6-$10 a tank. I don't believe in running higher than recommended as the engine ignition, timing and settings are meant to run on whatever octane they state. Where people probably see the benefit of 91/93 is the lack of ethanol and slightly more actual gasoline in the tank as oppose to "filler". Ethanol is a great fuel source, however, not really meant to be run in our motors. The wreak havoc on boat tanks, fuel lines and engine parts. I guess vehicles handle it a little better.”

Cair drives a 2014 Ram with a Hemi. He has experimented a little with the different octanes. “I used 87 for the first 18500 miles. Just to see what all the hype was about using 89, I tried it for the last 2 tank fulls. Honestly, couldn't tell the difference in the mileage or the way the truck ran.” Now obviously, this isn’t scientific, nor does it show what the effect is on the internal parts of the engine. It is just an honest answer to a simple question.

It sounds as if most owners use the recommended fuel with 89 octane. Everyone who used 87 octane seemed pleased and did not register any major complaints. It does sound as if using the higher 91 and 93 octane is simply wasting money because their engines can’t use it effectively.


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Comments

I own a 2017 dodge ram 1500 5.7 hemi . I ran 87 gas in it the first 12000 miles. And tried 89. Love it..it makes the truck throttle more responsive and less drag. Smoother transitions and definitely more power
In my 2006 Durango, with a 5.7 Hemi, (and 130k miles on it,) which is the same engine as a 1500 as far as I know. I used to just use 85 Octane all the time for a couple of years.. But then over the last few months, about once every other week, the engine would mysteriously cut out when at idle. Mostly, it would do that right after start up. But even happened after a long drive when I was coasting into my driveway. Then I noticed that when trying to accelerate from 40 to 55 mph, it would 'stutter' a bit. A very 'gentle' stutter, but still didn't feel right, as it was pretty gutless when at those low RPMs. (from 1000 to 1500 rpm.) So I decided to just try the 89 Octane just to find out if it made any difference. Wow. The stutter at low RPMs when trying to accelerate just disappeared. Much smoother power. And no issues with the engine dying after a start-up, or at any other time. It seems to make the computer happier or something. And the typical HEMI owners manual does recommend 89 Octane for 5.7 or bigger Hemi engines. Even though it does say running 85 Octane is OK. My theory is that the lower Octane was actually 'pre-igniting' under the compression at lower RPMs. Which is ironic since you'd think that you get more compression with higher RPMs. But RPMs have nothing to do with compression, and actually has to do with spark timing from the computer. It seems to me that at least 2 or maybe 4 cylinders were not firing at exactly the right time at the lower RPMs. Not enough to feel a complete 'mis-fire' I think. But enough to rob power until the RPMs got above 1500 or above 2000. Then everything smoothed out, even with the lower Octane fuel. Whatever the cause, I'm going to run 89 from now on. At least until I can get all the spark plugs replaced. (A $600 job at the local auto shop.)
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