What octane are we using?

[rlc2020]

I have been searching through endless threads about the benefits (or lack there of) of using mid grade or premium vs regular fuel. I thought it would be nice to see what everyone has been putting in their Rams

 

[R1nZX]

I've seen a thread similar to this on every car forum for every vehicle I've ever owned. Just a few reminders: modern engines have knock sensors, so they'll run on low octane fuel even if they were designed for higher octane. You'll get more power if you use the recommended octane, however. Using a fuel with higher octane has no benefit whatsoever. This is not my opinion, it's a well established scientific fact. You may "feel" like it runs better or has more power. That's called the placebo effect, which is also well established.

This is not aimed at the OP, just a few general facts about octane for those who are interested.

 

[Gondul]

I get my gas at COSTCO (Top Tier) and I get the 91 because it is cheaper than the 89 anywhere else.

 

[19RamLimited]

93 ONLY for me. Every fill up. Same in my 2013 in fact all my cars. Top Tier only also unless not available when traveling then I go with highest octane and best brand I can.

I dont care what anyone says I think its the best thing you can do in modern engines. You also need to make sure to really drive the **** out of it every couple of weeks. Heavy acceleration and really stand on the gas to burn out a lot of the deposits.. The ethanol in the gas and direct injection causes more deposits.

I know they say the engines adjust but the manual I have recommends a min of 89. There is no reason not to run the higher octane. Everyone has their opinion but my 13 has 100k miles on it and it runs like new until this day.

 

[riccnick]

I'm 93 only since October or so, and it made a difference in fuel economy for me, about 1 mpg over the long term.

 

[Jako]

I've seen a thread similar to this on every car forum for every vehicle I've ever owned. Just a few reminders: modern engines have knock sensors, so they'll run on low octane fuel even if they were designed for higher octane. You'll get more power if you use the recommended octane, however. Using a fuel with higher octane has no benefit whatsoever. This is not my opinion, it's a well established scientific fact. You may "feel" like it runs better or has more power. That's called the placebo effect, which is also well established.

This is not aimed at the OP, just a few general facts about octane for those who are interested.

I have a red card in my 2001 Dodge 1500, 8 cyl. 230 hp engine that says not to use higher octane. Came across it the other day while "cleaning out the console". I used 93 octane from Costco in my 2019 Ram 1500 Hemi and it seemed I got worse MPG. Any engineers out there that can give me an education on the use of higher octane than required?

 

[riccnick]

You'll get more power if you use the recommended octane, however.

Using a fuel with higher octane has no benefit whatsoever.

Huh?

The point is, even though our trucks will run on 87, they are designed to run on 89 and higher. Running a lower octane means that the truck will have to compensate for lower than optimal combustion, due to timing adjustments from detecting knock. Running a higher octane allows the engine to use optimal timing curves, and with how advanced engines are nowadays, I wouldn't be surprised if valve timing is adjusted as well. I'm not saying its a "MORE OCTANE, MORE POWER" hard and fast rule, I'm just saying that I'm tired of hearing how octane has no effect in a modern engine. Octane is an anti-knock rating, and detected knock forces the engine to run less efficiently, how are they not related?

(I'm not trying to say this just to you, it's an open discussion)

 

[Runagun]

Half tank 93 half tank 87. Go back and forth with each fill up.

 

[Limited_Ram]

Anyone running 87 when its clearly mentioned by the makers/engineers of the vehicle to run 89 or higher is simply trying to save a little money on gas. There is absolutely no other reason to run a lower grade and make your engine COMPENSATE for the difference...

 

[R1nZX]

Huh?

Sorry if I wasn't clear. What I was trying to say is that our engines are designed for 89 octane fuel. Using lower octane will produce less power, but there is no benefit to using an octane higher than 89.

 

[R1nZX]

I have a red card in my 2001 Dodge 1500, 8 cyl. 230 hp engine that says not to use higher octane. Came across it the other day while "cleaning out the console". I used 93 octane from Costco in my 2019 Ram 1500 Hemi and it seemed I got worse MPG. Any engineers out there that can give me an education on the use of higher octane than required?

I am an engineer, actually. Octane is strictly a measurement of knock resistance. Engines that use high compression, aggressive timing, and/or forced induction will experience knocking (detonation) with insufficient octane in the fuel. This can severely damage or destroy an engine, which is why modern engines detect detonation and adjust for low octane fuels. Maximum power is achievable only with the recommended octane.

Using a higher octane than recommended has no benefit, you're just paying more at the pump. I'm surprised by the card you found and can only assume they're trying to dispel this persistent myth that higher octane will somehow magically make more power in an engine that was not designed for it. There are no harmful effects to your engine by using higher octane than necessary.

 

[dutchman187]

I've been tracking different tanks on fuelly, playing with 87, 89, and 91/93, with and without ethanol For whatever reason, I also experienced my worst tank ever with the tank of 93. I drive pretty much the exact same routes for the duration of my tanks and drive conservatively. I'm not drawing any large conclusions from it, just stating it for the fact that it was. I'll continue to collect data on fuelly before settling on my go to.

 

[Jako]

I am an engineer, actually. Octane is strictly a measurement of knock resistance. Engines that use high compression, aggressive timing, and/or forced induction will experience knocking (detonation) with insufficient octane in the fuel. This can severely damage or destroy an engine, which is why modern engines detect detonation and adjust for low octane fuels. Maximum power is achievable only with the recommended octane.

Using a higher octane than recommended has no benefit, you're just paying more at the pump. I'm surprised by the card you found and can only assume they're trying to dispel this persistent myth that higher octane will somehow magically make more power in an engine that was not designed for it. There are no harmful effects to your engine by using higher octane than necessary.

Thanks - I will post the card along with my 2001 sticker against my 2019 sticker - eventually!

 

[Edwards]

Or take the scientific approach. Hand calculate your mileage and try all three octanes, keeping track of the price you paid. If you see a difference in mileage you can then figure out if the extra mileage paid for the increased cost of the gas. Getting .001 MPG better on 93 will never pay for itself due to the higher cost you are paying. Yes, it's technically higher MPG, but you are paying for the privilege and could go 10,000 miles down the road cheaper on 89.

I get slightly higher mileage on 93 but it doesn't pencil out vs. 89. And I see a big drop off with 87, so 89 is what I use now based on my real world experience.

 

[Yelzelity]

Anyone running 87 when its clearly mentioned by the makers/engineers of the vehicle to run 89 or higher is simply trying to save a little money on gas. There is absolutely no other reason to run a lower grade and make your engine COMPENSATE for the difference...

I use 87 because I want the freshest gas possible, around here I dont see many running 89. I worry about bad/stale gas.

 

[SpeedyV]

I've been tracking different tanks on fuelly, playing with 87, 89, and 91/93, with and without ethanol For whatever reason, I also experienced my worst tank ever with the tank of 93. I drive pretty much the exact same routes for the duration of my tanks and drive conservatively. I'm not drawing any large conclusions from it, just stating it for the fact that it was. I'll continue to collect data on fuelly before settling on my go to.

In previous threads on this topic, I documented my experience—the opposite was true. I know (as an engineer myself, among other things) that the truck shouldn't achieve better economy on 93 vs. 89 if designed for the latter. I've been alternating fill-ups between 89 and 93 to see if I can establish a pattern, but there are just too many variables (e.g. weather, specific driving patterns, traffic, etc.) to claim anything statistically significant. I do see 'instant' economy 1-2 mpg better on the same stretch of road when running 93, unless the computer is just being 'fooled'. My best tank ever was on 93, but my second best was on 89. The experiment continues...

 

[Pribilof]

I run 91 because our state has crap 85 and "mid grade" is 87. Manual clearly states 89 minimum.

 

[JayMann]

in the CostCo crowd here - they only have 87 or 91 so 91 it is (or 93, can't remember exactly - I just know that they for sure don't have 89)

 

[klail]

I run 91 because our state has crap 85 and "mid grade" is 87. Manual clearly states 89 minimum.

Recommended, not required. It specifically says "having an octane range of 87 to 89.

 

[dn325ci]

I’ve been running Costco 87 in mine over the 1,400 miles since new. I thought I heard part-throttle knock/pre-ignition/detonation on the last tank and I heard some again on this tank. I’m going to switch to Costco 93 and see what happens to knock and mileage.