87 or 89 Gas which do you use?

[Idahoktm]

I've been running 87 in mine because up until a few days ago I didn't realize FCA recommended 89. It runs great with zero knocking and I'm getting about 15.5 mpg all city driving and that's with oversized tires. If I can get 1-2 mpg better fuel economy with 89, it won't make up for the difference in cost but I'm curious if it will run noticeably better. I'll run 89 in the next tank and report back.

 

[theblet]

87 all day everyday. Can't even get anything higher at my home town station. They only recommend 89 cuz that's how they achieve those rigged fuel mileage numbers they print on the window sticker.

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But also to give the highest hp/tq numbers. That's why i don't use it unless im towing heavy. The extra cost for 89 doesn't cover the mpg gain. I would come out behind. I rather save $10 a tank

 

[mikeru82]

But also to give the highest hp/tq numbers. That's why i don't use it unless im towing heavy. The extra cost for 89 doesn't cover the mpg gain. I would come out behind. I rather save $10 a tank

That would mean in your area 89 octane costs over 30 cents per gallon more than 87 (assuming 33 gallon tank). In my area the difference between 87 and 89 is 10 cents per gallon at most gas stations. My average fill is 29 gallons, giving me a savings of $2.90 per tank if I opt for 87 octane. Not worth it for me. I'll stick with 89 until there is a bigger difference in price.

 

[GKIII]

That would mean in your area 89 octane costs over 30 cents per gallon more than 87 (assuming 33 gallon tank). In my area the difference between 87 and 89 is 10 cents per gallon at most gas stations. My average fill is 29 gallons, giving me a savings of $2.90 per tank if I opt for 87 octane. Not worth it for me. I'll stick with 89 until there is a bigger difference in price.

It's anywhere from a 20-35 cent difference in my area. I still use 89, since I hear the "light" knocks the manual talks about only with 87.

 

[BluegrassMotorsport]

That would mean in your area 89 octane costs over 30 cents per gallon more than 87 (assuming 33 gallon tank). In my area the difference between 87 and 89 is 10 cents per gallon at most gas stations. My average fill is 29 gallons, giving me a savings of $2.90 per tank if I opt for 87 octane. Not worth it for me. I'll stick with 89 until there is a bigger difference in price.

In my area, the difference is exactly $0.30 per gallon. Some stations offer 89 for mid grade and others offer 91 - but the difference is still $0.30 over 87 regardless. Then it's another $0.30 higher for 93.

 

[Scram1500]

I use 93, unless I can find 94. The Hemispherical motor loves it

 

[BowDown]

Its about a .30 cents spread here but Costco's 93 is is .40 cents cheaper than everyone else's 93.
Those to the right are for 87. With Texas heat and high IAT's I use 93 for safety. My original plan was 89 in the winter and 93 in the summer due to heat but Costco's 93 is as cheap or cheaper than everywhere else's 87

 

[Sal731]

Guys guys. Forget this thread. Put whatever octane you like in your truck. Everybody is getting different numbers anyways when it comes to mpgs. I use 93 but I drive aggressive so I’m only getting 16 and change mpg. All highway. I like to hear my borla exhaust!!!

 

[GKIII]

Guys guys. Forget this thread. Put whatever octane you like in your truck. Everybody is getting different numbers anyways when it comes to mpgs. I use 93 but I drive aggressive so I’m only getting 16 and change mpg. All highway. I like to hear my borla exhaust!!!

I get 14 and change with my 89

 

[Idahoktm]

Its about a .30 cents spread here but Costco's 93 is is .40 cents cheaper than everyone else's 93.
Those to the right are for 87. With Texas heat and high IAT's I use 93 for safety. My original plan was 89 in the winter and 93 in the summer due to heat but Costco's 93 is as cheap or cheaper than everywhere else's 87


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I like buying gas at Costco, but they are only about 7-10 cents per gallon cheaper than the Mobil station I usually go to and the lines at Costco are insane. I'm not waiting 4 cars deep to save 7-10 cents per gallon.

 

[HSKR R/T]

I saw a video on youtube where a guy logged (hp tuners) his hemi with different gas. The point here is that the computer pulled much more timing on 87, than it did on 89. So while the "wide variety of reasons" may be true, those reasons would still be there when running on 87 vs 89 when that is the only difference between tests. What is being claimed is that these hemis so obviously run far better on 89+

The comment I was replying to said the PCM was pulling timing even with 93 Oct. It's pretty obvious it's going to pull timing on 87. Owners manual even tells you that.

 

[Mb7640]

I use 89 for 5.7 since that's what the manual call out for.

 

[theblet]

That would mean in your area 89 octane costs over 30 cents per gallon more than 87 (assuming 33 gallon tank). In my area the difference between 87 and 89 is 10 cents per gallon at most gas stations. My average fill is 29 gallons, giving me a savings of $2.90 per tank if I opt for 87 octane. Not worth it for me. I'll stick with 89 until there is a bigger difference in price.

2.75 for 87, 3.10 for 89

 

[Fatherdeath]

89-91.

87 is about 3-4mpg lower for me