87 vs. 89 octane

[chuck]

I just noticed in my manual that is says 89 octane is recommended for the 5.7l Hemi, but 87 octane is acceptable.

Has anyone run both octanes and seen any noticeable difference in performance or mileage with one verse the other? I would love to avoid spending the extra money at the pump but I would be willing if it's worth it.

 

[ATXHEMI]

I doubt you'll see that much dif from 87 to 89.

 

[chuck]

I doubt you'll see that much dif from 87 to 89.

That's what I was thinking. I can't imagine it would be worth the extra money since I just use mine as my daily driver and the mods are all just a hobby. I don't need any extra performance for any real reason haha

 

[2013-ram3500]

With my ZL1 camaro, the computer gets used to a certain fuel grade mapping, and I have to pull 2 fuses overnight to reset the computer. Once the fuel map is reset as long as I stay running 93 octane, there is a huge difference. If you start running 91 again, I can tell a performance drop. Not sure if 87-89 octane makes that much of a difference. Not even sure if this works with rams?

 

[Jim45498]

I can't tell any difference so I am going to go with 87

 

[Mega-Hemi]

There are many threads on this all over the internet. Some people run 87 octane all their lives and have no problems what so ever, others claim that the pinging from running the lower octane causes the tops of the pistons to deteriorate. The choice is yours. I've always run 89 in my HEMI just for a little insurance.

 

[smiley]

I personally feel it is doggy on 87 but could be mental too.


$miley

 

[joeshemi]

i run 89 cause its recommended,until i get a tuner.

 

[msorbara10]

I dont think it runs as well with 87 IMO. I havent thought about resetting the PCM after changing octane. I want to reset mine tomorrow because I had my truck for 4 months. My first tank was with 87 but every other was 89. Maybe it will run even better after resetting the PCM

 

[Appauldd]

I've noticed my truck runs like poo on 87. It will even ping at low speed high load conditions. 89 for me and about every 3rd fill up I do 93.

Has anyone pulled the stock spark plugs to see if they are all gaped to the correct value? I ask because this might show some inconsistency that could lead to my poor running condition.

Paul

 

[smiley]

If I recall they were correct when I changed mine at around 33k or something like that.


$miley

 

[20ram12]

When I first bought the truck I was putting 87, then after a little while I went to 87 noticed slight improvements but, nothing drastic. Finally, switched over to 93 octane when getting a tuner and notice big improvements. I find it burns slower and it idles smoother.

 

[chuck]

Awesome guys thank you all for your input. It seems like the majority opinion is that 89 will do better. I have to fill up tomorrow so I'm gonna put 89 in it, and run the 89 for the next 2 or 3 fill ups. I've been running the 87 for the last 2 fill ups so I'll be able to do a pretty good comparison. I'll post my opinion in a couple weeks just in case anyone else is curious.


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[mattman_13]

My company pays for my fuel so I have to get 87. Hence me buying a diablo and running the 87 tune. No st or lt knocks.

I emptied it out one weekend and ran 93 in it till bout half a tank. Filled it back up just to make sure I was getting fuel 93 and tried to 93 performance tune. It was better but no where near worth the extra I'd be paying. Mines got plenty of grunt on 87 with 35x12.50 and 3.55

 

[chuck]

My company pays for my fuel so I have to get 87. Hence me buying a diablo and running the 87 tune. No st or lt knocks.

I emptied it out one weekend and ran 93 in it till bout half a tank. Filled it back up just to make sure I was getting fuel 93 and tried to 93 performance tune. It was better but no where near worth the extra I'd be paying. Mines got plenty of grunt on 87 with 35x12.50 and 3.55

Ok good to know. Maybe then the small step up in price to 89 would be worth it? Since its not as much money as the 93.


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[msorbara10]

My company pays for my fuel so I have to get 87. Hence me buying a diablo and running the 87 tune. No st or lt knocks.

I emptied it out one weekend and ran 93 in it till bout half a tank. Filled it back up just to make sure I was getting fuel 93 and tried to 93 performance tune. It was better but no where near worth the extra I'd be paying. Mines got plenty of grunt on 87 with 35x12.50 and 3.55

If I had my company paying for my gas I would have so many miles on my truck right now haha. Good idea running a 87 tune BTW

 

[chuck]

If I had my company paying for my gas I would have so many miles on my truck right now haha. Good idea running a 87 tune BTW

Hahah you and me both man. As I just posted on another thread, I've had my truck for 2 weeks now and I've already put 1,100 miles on it. And thats with the "oh damn, I better cut back on driving" mentality.

 

[garner]

Depends on the truck. My R/T seemed to run best on 93, with it feeling slower on 89 and an absolute dog on 87.

So this truck I've been running 93 from the beginning until now(29,800 miles) except for like 3 fill ups with 89 when the gas station was out of 93, and then these past 2 tanks I've ran 87. Truck seems to be the same with any octane

 

[chuck]

Depends on the truck. My R/T seemed to run best on 93, with it feeling slower on 89 and an absolute dog on 87.

So this truck I've been running 93 from the beginning until now(29,800 miles) except for like 3 fill ups with 89 when the gas station was out of 93, and then these past 2 tanks I've ran 87. Truck seems to be the same with any octane

Thanks for the input. I can definitely see how it would be more important to run a higher octane on the R/T


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[Litenyaup]

Thanks for the input. I can definitely see how it would be more important to run a higher octane on the R/T


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Don't see why the rt would need any better fuel over another 5.7.....same motor just in different bodies correct?

I have a 2011 sport with the 5.7, it has 15000 and I have out both 93 and 87 with not feeling any difference in power or idle. I use Mobil or Chevron fuel so I don't know if that makes a difference.