I use 89 seems to run better in my opinionJust want to find out what fuel grade people are using.
I have the 2019 Rebel with the 5.7 Hemi (no e-Torque) and the manual recommends the 89 octane but 87 is acceptable.
Trying to figure out if I should use the recommended 89 octane or the 87.
What is everyone else using?
Thanks.
I'm not that hard up that I have to worry about going with 87 to save $8 per tank.
Agree.
I used to get a bit bugged by so many repeat questions on other forums (automotive, solar etc) when a simple search of the term would bring it all up however it's just too easy to type a question and post it. Once I made a comment about the issue, a moderator replied and said that the purpose of the forum was education so I guess "bring it on".
It is a bit confusing though with octane, E-10 and E-15 or E-85 fuel, the effects of altitude and all. Back in the day' you listened for the "pinging" and then either (manually) retarded the timing or stepped up in octane. Haven't been doing that for decades now!
As ethanol use and % increases, there may be more concerns over what the increased percentage of ethanol is doing to the fuel systems and longevity.
I haven't really read this link but it sounds interesting:
Ethanol and Octane For Beginners
https://mnbiofuels.org › media-mba › blog › item › 1511-octane-and-ethan
Anyway, I use 87/89 as I see it available. When at Costco, it's cheaper fuel so I throw in some 91 (1/2 tank) at times. I try to avoid 85 if at all possible, since our hemi's are rated for 89 I think. There's those who swear it 1 - makes no difference or 2 - gives them better mileage and more power. Since there are so many variables between tanks, I don't see how the average user would be able to really tell (scientifically). When I drive the same route the same way daily, and get 2-4 mpg difference in average mileage over a tank, I have to wonder if it's octane, water or other impurities in the fuel or what...
Increasing ethanol use has been a positive for fuel system longevity. The auto parts stores where I live do not sell or recommend fuel system cleaners anymore because the ethanol fuels have made them unnecessary. Ethanol helps prevent and remove deposits in fuel systems.
That’s not true at all. Almost all newer vehicles rely on their knock sensors to control timing, and the more octane (within reason) you run, the more timing the computer allows, which gives you more power. There really won’t Be any benefit seen past 91-93 octane, but most definitely a difference using at least 89. It will also help with throttle tip in performance.87 for my truck. No point in higher octane. Not gonna gain power and any mileage increase will be minimal, the extra cost will eliminate any savings.
There is a caveat to what he stated... ethanol is alcohol, and alcohol is fantastic for the cleaning of components... HOWEVER, for vehicles not designed for it, it can be dangerous to use as it can destroy rubber lines, aluminum components not properly treated for alcohol, and it is hygroscopic, meaning it absorbs water and is not safe for extended storage in your tank. In addition, your computer is not capable of properly adjusting beyond a certain percentage of alcohol content without a flex fuel sensor, and it may also exceed the capacity of your fuel system as ethanol reduces fuel economy and efficiency.Can you supply a link about that? That's the opposite of what I've ever been told or read, especially in regards to small engines (2-cycle and motorcycle) and any car designed only for E10.
I know the motorcycle industry has been the most against E15 or higher due to blender pumps use and possible too much ethanol getting into the fuel system.
That’s not true at all. Almost all newer vehicles rely on their knock sensors to control timing, and the more octane (within reason) you run, the more timing the computer allows, which gives you more power. There really won’t Be any benefit seen past 91-93 octane, but most definitely a difference using at least 89. It will also help with throttle tip in performance.
edit - before I get the “well it doesn’t feel faster” claims, we’re talking 10-15 hp. It’s not huge, but as someone who has been building race cars and tuning forever, I like having whatever on tap I can, and knowing what to look for, I can feel the difference exactly where I’m supposed to with the better octane.
unless its been specifically tuned for higher octane, you will see no benifit. You are right about the knock sensor. But again, chrysler would have had to tune make performance on 89 octane for it to be beneficial. And if they did, 91-93 wont make abit of different other then making your wallet lighter.
definitely can't hurt. i run 91 from sunoco in my truck. wish we had a costco around here. my cost/gallon is usually mid 3'sTrue.
For me I still use Costco 91 octane since they don't have 89. Reason is it's still 10 cents (or more) cheaper than other stations 89. I'm assuming I'll get the same benefit of 89 even though I'm using 91.
definitely can't hurt. i run 91 from sunoco in my truck. wish we had a costco around here. my cost/gallon is usually mid 3's