Do you use the recommended 89 octane?

Great thread, I was looking for something like this since I got my sport 2 weeks ago. My old man tells me im being stupid for using 89 when the manual says 87 is acceptable as Im just wasting money. I noticed my first tank I filled up with 89 got at least 100 miles more then the tank I just filled up with 87. I went with 87 since the costco around the corner from me just opened their Costco Gas station. I wish they had 89, they only sell 87 and 91, although for $3.08 for 87 it was tough to complain..I should give their 91 a shot at $3.39, since their 91 is even cheaper then Exxons 87 at $3.42.

But I have noticed with the 87 I have more hesitation on take off, and the Eco doesnt stay on consistently as it does with 89. My MPG also sits between 8-11 with 87, and 15 on the highway, where with 89, i was at least getting between 11-14 in town, and 17-19.8 on the highway.

my 2012 says to run on regular unleaded, that is what I use.

FETTO is yours a 2012? I would assume it is since its 2 weeks old. If so what does the manual state. And why different then Cotonymopar?

Originally Posted by hounddogg

FETTO is yours a 2012? I would assume it is since its 2 weeks old. If so what does the manual stante. And why different then Cotonymopar?

Hey...yeah mines a 2012. Here's my manual. I have the 5.7L Hemi..

I just found that on line. You beat me to it. It says the same as before. 87 acceptable but 89 recommended. It appears that some owners selectively read their owners manual. The 4.7 says 87 octane is OK. The hemi says 89 preferred, but if you want to sacrifice performance and fuel mileage, you can use 87.

I use 89 just a few dollars more a fill up and its recommended.

89 here in NE has ethanol in it, so it ends up being cheaper. I lose some mpg, but it's a truck... I didn't buy it to net 35mpg.

I always run 89 in my truck. The truck just feels better to me with it in the tank ,not huge power differences just smoother idle and what not. Although the girlfriend did put half a tank of 87 the other day and it just didn't seem right......

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I use 87 and so far so good. Why the manual recommended 89 it did state that 87 could be used. I just got back a couple of weeks ago from a trip and I got 19.5 miles to the gallon average on the open road. Again using 87 octane. No pinging could be heard so I think it is safe to day that 87 octane will work just fine.

I have a 2011 Sport 4 X 4, 5.7. I run 89 only because manual says "accepts 87 but recommend 89". I have notice about 1 MPG better when using 89, but no difference in performance. My thought is that it is not much difference between price of those 2 so just go with what manuf recommend. Another big thing is almost all fuel in my area (Hampton Roads, VA) has about 10%-15% ethanol which I think makes our trucks less efficient.

I figure when the dealer fills up the tank when you buy it, they don't use 89 anyways

As mentioned before. You probably won;'t hear a 'ping' because the system picks it up in a split second and retards timing etc. One of the reasons of 89 octane is to get the advertised h.p.,fuel mpg and such. It obviously is needed somewhat other wise the subject would not be addressed in the owner's manual. Capiche

89 everytime.

I know this is not a Mustang 5.0. I was reading on a Ford sales site about 2012 Mustangs with 5.0. Two different horsepower numbers are given. One on regular and one on premium fuel. I think it was was 18 or 19 horse difference. Thats a lot of difference be it 87 octane or 91 plus octane. I'm sure these Hemi's react similar.

Originally Posted by hounddogg

I know this is not a Mustang 5.0. I was reading on a Ford sales site about 2012 Mustangs with 5.0. Two different horsepower numbers are given. One on regular and one on premium fuel. I think it was was 18 or 19 horse difference. Thats a lot of difference be it 87 octane or 91 plus octane. I'm sure these Hemi's react similar.

That is what I was thinking too which is why I do the 89.

Originally Posted by hounddogg

I know this is not a Mustang 5.0. I was reading on a Ford sales site about 2012 Mustangs with 5.0. Two different horsepower numbers are given. One on regular and one on premium fuel. I think it was was 18 or 19 horse difference. Thats a lot of difference be it 87 octane or 91 plus octane. I'm sure these Hemi's react similar.

That would be something I'd be very interested in seeing tested on a dyno somehow. It would certainly make up my mind.

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I used to use 87 until i started reading around here. Now its 89 every time. I found a big difference. It really felt a lot more smooth and more powerful in my opinion.

87 octane here. 5.7 hemi Sport.

Winter time now, I am remote starting a lot, so I am idling away a lot of gas. So I am using 87 octane now. I am running the 87 octane tune on my Superchips as well.

Come summer I will load the 91 tune, and run 91. I may try the 93 tune if gas is low, as we can get 94 octane at the Petro Canada's that used to be Sunoco. It is only 2 or 3 cents more than 91.

Me and my co-worker bought our 2011 Rams a few days apart. He got a blue big horn HEMI and I got red sport HEMI. He swears by 87 all day every day, but complains about MPG all day everyday. I run 89 always unless I buy my fuel from Sam's Club where you pay about the same for premium and no option for 89. Through our conversations, I get about 1 mpg better than he does in the city and about 2 better on highway. Both trucks are 4X4 Crew Cabs so they are almost identical. We both have similar driving habbits. I cannot tell if my truck puts out more HP with better gas, but it does appear to give a little better MPG. My reasoning for switching from 87 to 89 was because manual says accepts 87, but recommends 89. When we are talking $80+ to fill these big boys up, an extra dollar or 2 for better gas should not kill us. Hopefully it will save some expensive repair in the long run.