rlc2020
Well-Known Member
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
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'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.
You'll get more power if you use the recommended octane, however.
Using a fuel with higher octane has no benefit whatsoever.
Huh?
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?
Thanks - I will post the card along with my 2001 sticker against my 2019 sticker - eventually!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.
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...
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...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.