I've searched for this and read a few threads about what kind of gas we're supposed to be putting in our hemis. In the manual it says that 89 is recommended but 87 and 89 can both be used. I've tried both and did not see a difference in either. Mileage or performance. Is there a risk involved when using the 87 octane? When reading the other threads, people have said there would be a risk of damaging your engine. Is this a fact or just a myth? 87 is 15 cents/gallon cheaper here and that can add up over time. Especially with my 25 mile commute (one way).

 

I use 89 it cost a little more but i get 60 miles give or take more and I believe my truck runs better.Not sure if it will mess the motor up if you use 87 .

 

I use 89 but 87 should be safe if you are not hearing any engine knocking.

 

I only run Shell 89 in my 4.7, it's not a HEMI but I found I get the best mileage and performance with it.

 

89 is better and burns better. with 87 your engine will start knocking after a coule tanks!

 

yah deffinitly use 89, granted it costs a lil more but like the others i have noticed an increase in fuel mileage and she deffinitly runs better. everyonce in awhile i'll run a tank of the V-power 93 just for ****s and giggles lol, just my $.02 worth

 

Not true, no knocking here and 87 is all I use. Let's stick to the facts.

I don't think saying 89 burns better is true either. Doesn't a higher octane prevent pre detonation? So it is actually more difficult to burn.

 

I've used 87 for 41k miles and engine runs great. 20.6 highway mpg hand calc. Hemi, QC 4x4.

 

Actually the higher the octane rating the faster detonation is. Which is why higher performance cars use 91 or higher (if you can find it..LOL). I used to have a 01 Neon with a built motor and turbo from Hahnracecraft I used 91 in it...sometimes I would go to this one gas station in Vegas that sold 103 OCTANE for whenever I was feeling froggy . But for the truck I only 87, with performance mods I might have to bump it up to 89 or 91.

 

First off, I use 89, and always will (or higher). I think we can all agree that Engine Knocking is a bad thing, right? Ok, lets see... all of you with either a CAI, or aftermarket exhaust raise your hands. For those of you that raised your hands, do you really think that you can hear knocking? The knocking that 87 octane will or could cause is going to be so quiet that you'd never hear it over your intake system. Another point I'd like to point out, there are many people on here that don't really know a lot about their trucks or have an automotive background. Don't get me wrong, I'm not ragging on the guys that don't have mechanic backgrounds, but the point is most people can't hear or even know what their hearing when the engine IS knocking. Octane knocking isn't like a tired diesel engine knocking, its quiet for the most part. I use 89 becuase my mileage is good now, and has been since I've had the truck. It's also piece of mind. Its not like DCX recommends 89 in all their cars/trucks. If they did, then you'd think something was up, and then you could argue thats it not needed, but only the Hemi needs 89 (not including SRT vehicles of course). Thats just my $.02