minimum octane

[hemifever]

What's the octane recommendation on these '11 and '12 Hemi trucks? Seems the logs I see with 87 octane and stock timing curve are ridiculous with knock retard. What's the owners manual state?

 

[kkreit01]

"Recommended" for the Hemi is 89. I think all 5.7s recommend 89, but most run fine on 87. I know my '09 Aspen was the same.

 

[smiley]

I agree HEMI 89 is recommended on everyone I have seen all years.

 

[Hemi450hp]

89 is recommended like stated. Lots of guys still run 87, but if you are performance oriented, it should be no less than 89...and I would always run 91 or 93 if using a tuner. The difference in price between 87 and 89 is only about $5-$8 per tank, so its not much more money for a much better running engine.

 

[smiley]

Where I live the cost between 87 and 89 is very close a dollar or less per fill. Going premium is about $.70 per gallon more which if I am empty is about 21 bucks difference unless I am crazy.

 

[arod412]

what is the long term effects of running 87? I pretty much run that because gas prices. I know the computer adjust for the type of gas, but is there any long term affects that i should worry about if i run 87 the entire time?

 

[Hemi450hp]

Where I live the cost between 87 and 89 is very close a dollar or less per fill. Going premium is about $.70 per gallon more which if I am empty is about 21 bucks difference unless I am crazy.

The difference between 87 and 89 out here is only about $.20/gallon. Its crazy how that differs by location.

The computer will adjust if it detects knock with the lower octane fuel, so you arent going to blow up your motor...but you will have a stronger and better running motor if you use the higher octane and dont have any knock.

 

[arod412]

The difference between 87 and 89 out here is only about $.20/gallon. Its crazy how that differs by location.

The computer will adjust if it detects knock with the lower octane fuel, so you arent going to blow up your motor...but you will have a stronger and better running motor if you use the higher octane and dont have any knock.

Thanks.... once in a blue moon i might get 89 or higher if i have a long road trip, but with gas getting ready to rise again, it's just better to get the cheaper gas.

 

[TheMaddog]

I've done all the octanes, and for some reason, 87 gives me the best mpg.

 

[SILVER_BULLET]

i've done all the octanes, and for some reason, 87 gives me the best mpg.

mine hates it it runs like crap you can really feel how lazy it gets with that gas and i get litteraly like 7mpg

 

[ram-head]

I ran a couple tanks of 87 in my last Hemi. Then I read about the ticking/knocking and started running 89. Helped a little. When I got a tuner in 2008 I started running 91. I haven't run anything less since, even on my 2012 without tuning.

 

[CashDollarJack]

Ive heard 89 is optimal. i run 93 period no if ands or buts and she runs like a champ. Looking forward to an intake, exhaust and a tuner.

 

[iSlacker816]

Does spark knock kind of feel like a miss under a load?

 

[Big Green]

Wow, my Ram's knock retard must've been something terrible to generate a thread lol. I hereby do solemnly swear to run 89 octane at a minimum in my Ram. On a side note, thanks again for the custom tuning, Sean!

 

[redsand]

I get a little ST knock, up to 3 under WOT and 5 or so when I'm pulling a hill. Going to try a different station tomorrow when I fill the truck to see if that makes some difference or maybe its just this crappy winter gas??
Doesn't seem to bother the truck any though, pulls hard.

 

[Big Green]

Yeah, the knock was present on the log, but my Ram was running stronger than ever. Switching to 93 and never looking back.

 

[ram-head]

Since we're on the topic of octane, here in Colorado Springs (elev. 6,010 feet here on my couch) 93 octane seems to be a rarity, like a unicorn rare. Is there a benefit to me going out of my way to find it?

 

[Ducontar]

here in Brazil, has a gasoline (podium) with 95 octane, but here in Brazil all gasoline contains a percentage of alcohol, I wonder if I can use in my ram 2011 hemi, with diablo trinity without damaging the engine?

 

[redsand]

Since we're on the topic of octane, here in Colorado Springs (elev. 6,010 feet here on my couch) 93 octane seems to be a rarity, like a unicorn rare. Is there a benefit to me going out of my way to find it?

I've read that elevation has effect on octane and that a 91 should perform similar to a 93. I'm only at about 3300 and tried the stock 93 tune on 91 and got both ST and LT knock just driving through my neighborhood.
What part of the Springs do you live in? I lived there for a stint, up by Powers and Woodmen. Wish we were still there actually.

 

[ram-head]

Just moved over off Hancock and Circle. I know engines don't perform well at higher altitudes, but do you think there's a risk of running rich with 93 because of the thinner air? My limited knowledge of mechanics says the computer would adjust for the better gas and improve MPGs, even if only slightly.