87 octane vs 89 octane, fuel economy differences

[Dave01]

You don't get to agree or disagree with facts, chief. Feelings aren't facts. Math, however, is.

The facts are I can drive the 05 Tahoe for LESS than he spend on his moronic EV. Go back and re-read my post after you remove yourself from the fetal position that this triggering conversation has apparently placed you into.

Next?

I'm all set, thanks. I enjoy this forum, enjoy conversations, and BTW enjoy your posts in general. But if you can't discuss without me being "chief" and being triggered and in the fetal position, your ev owner and his car being morons, I just have better things to do. You ought to sit back and reflect on why you can't have a conversation without calling people names.

So I'm back to '87 vs. '89 octane for this thread, and seriously have a great weekend, I'm very glad it's Friday afternoon!

 

[gimmie11s]

I'm all set, thanks. I enjoy this forum, enjoy conversations, and BTW enjoy your posts in general. But if you can't discuss without me being "chief" and being triggered and in the fetal position, your ev owner and his car being morons, I just have better things to do. You ought to sit back and reflect on why you can't have a conversation without calling people names.

So I'm back to '87 vs. '89 octane for this thread, and seriously have a great weekend, I'm very glad it's Friday afternoon!

All good sir. People can like what they like as it relates to autos. What they're not entitled to is creating their own reality that contradicts math and known fact.

 

[G Mcpherson]

Gee I could do a Lot with 60K.

 

[SwampCat]

Compared to other vehicles I’ve had, the Rams MPG calculator seems to be very accurate and fluctuates a lot more “real time”, so it’s more sensitive to idling and brief hard acceleration.

I’m curious to see how my experience is with changing octanes, since mine is new I’m “breaking in” with premium probably till the first oil change. Then I’ll switch to regular unless I’m on a long road trip or towing heavy, which is what I’ve always done. My previous vehicles have been minimally impacted but I wonder if the Rams more sensitive mpg calculator will show anything obvious. Even my Maxima with a higher compression motor and “recommended premium for best performance” is minimally impacted in day to day driving with different fuel types.

I always run top tier and preferably “name” brands of fuel though. I had a buddy with a newer Accord whose motor blew up just outside of the warranty and the dealer said it looked like he was running too much cheap gas.

 

[Keeper79]

87 unless I am going to be towing. MPG does vary, I live in the middle of no where, just cruising along minding my own business I will see 18 to 19mpg. If I go into town that is 10 miles away it will quickly drop to about 15mpg due to stop lights and such.

Branded gas is different than non branded, wife worked for a petroleum company for several years and the blends, taxes and everything about gas is purely insane. She will not run unbranded gas in her 6.4L Challenger, I am not as picky but try my best unless I am towing and then really avoid it.

 

[Crusty old shellback]

I thought you said you lived in the middle of nowhere?
Its 25 miles for me to town and the nearest store/gas station.
But best I can do is 14.5 on the highway or back road. Usually get 13.

 

[Keeper79]

I thought you said you lived in the middle of nowhere?
Its 25 miles for me to town and the nearest store/gas station.
But best I can do is 14.5 on the highway or back road. Usually get 13.

Well if I drive towards town its 10 miles, go in the other directions is over 30 miles. The amount of people who stop and ask where they are or the nearest main road is hilarious. I live on the main road, just nothing really out here.
Recently did a trip for a motorcycle track day 700 miles away. Pulling a 16x7 v-nose with 4 motorcycles and all my needed crap and averaged 13.0 - 13.3mpg, buddy with his 1500 chevy with the new I-4 with turbo pulling a 6x12 with two bikes was getting 8.0mpg. Always laughed at my gas guzzler till towing time.

 

[Crusty old shellback]

Yea, I'm down a 2 lane paved road from the highway. 5 miles down that road. Then turn off onto a dirt road for 2 miles.
I have found out that above 70 MPH, it doesent matter. Same MPG. Below that does change with speed.

 

[Zeeman]

I have been running 89 octane since day 1 in my 2023 6.4, and my average economy in town is 12.5 hand calculated. After reading on here about folks using 87 octane, I decided to switch over to see if any difference. Well, after running 87 for 3 tanks, my hand calculated economy has dropped to 11mpg. Same gas stations, same roads, same speeds. I will switch back to 89 now. Truck has 3300 miles on it.

I get 1 mpg better with High octane gas. You must have 4:11 gears as you should be averging in 14's with 3:73 by trip computer

 

[Dave01]

I get 1 mpg better with High octane gas. You must have 4:11 gears as you should be averging in 14's with 3:73 by trip computer

Not necessarily, depends on how and where you drive. He says his results are from in town driving, I find that my mileage is not very good on in town type stuff. Granted I do have 4.10's but there just isn't all that much difference with 3.73's.

 

[JDMHero47]

I ran nothing but 89 in my ‘21 but decided to give 87 a go with the ‘24. Only thru the first tank so didn’t calculate that one yet but it looks like I’m getting maybe 11.5

Truck only has a smidge over 400 miles on it so it’s a bit early.

Do you guys not have 91 available?

 

[Firebird]

Do you guys not have 91 available?

Not in my part of Florida, we have 87/89/93

 

[JDMHero47]

Not in my part of Florida, we have 87/89/93

Ha, that's even better then; you have 93. Why don't you guys try running 93 instead of 89?

I learned the hard way that anything less than the best makes towing a horrific experience on a gas motor. After that, I don't even think about it at the pump regardless if I'm towing or putting around town. I always hit the highest grade without looking at the price tag. Granted, 91 is only $.30 more than regular (87) in my area, so take that with a grain of salt please.

 

[Firebird]

93 here as almost $1 more than 87, but 89 seems to work very well for me

 

[Gondul]

Ha, that's even better then; you have 93. Why don't you guys try running 93 instead of 89?

I learned the hard way that anything less than the best makes towing a horrific experience on a gas motor. After that, I don't even think about it at the pump regardless if I'm towing or putting around town. I always hit the highest grade without looking at the price tag. Granted, 91 is only $.30 more than regular (87) in my area, so take that with a grain of salt please.

These things don't need to run on that high of an octane..
There is plenty of data out there showing that running a higher octane than needed does *nothing* (except burn a hole in your wallet)

I ran 89 for 3 months and then 87 for 3 months, there was no statistical difference in fuel consumption or perceived power...
Was this scientific and controlled? Of course not.... just my half assed attempt to quantify any difference between 87 and 89,

I just get 87 Top Tier gas....
FWIW, YMMV...

 

[Dave01]

These things don't need to run on that high of an octane..
There is plenty of data out there showing that running a higher octane than needed does *nothing* (except burn a hole in your wallet)

I ran 89 for 3 months and then 87 for 3 months, there was no statistical difference in fuel consumption or perceived power...
Was this scientific and controlled? Of course not.... just my half assed attempt to quantify any difference between 87 and 89,

I just get 87 Top Tier gas....
FWIW, YMMV...

Same here. I buy only 87 at this point. I put a lot of highway miles on, also tow a few times a week at 8000 lbs. for 40-90 miles. Like you I have no science behind this, just what I've experienced.

 

[Rodehawg97]

More important than straight up octane is running non ethanol gasoline. Gasoline is more energy dense than alcohol so running non ethanol gasoline will give you more power and mileage. Since I started using 90 octane non ethanol unleaded gasoline my fuel mileage has gone up 8 to 10% and my truck noticeably produces more power.

 

[whitexc]

Non ethanol or Rec Gas as it’s referred to around my parts is very expensive, as in close to $1.50 more per gallon. I do try to run top tier gas and if I hook the 5er up I will run 89 or 93 depending on the station. That’s likely my mind telling me it does something when towing to justify the cost.


Sent from me

 

[unclelala]

More important than straight up octane is running non ethanol gasoline. Gasoline is more energy dense than alcohol so running non ethanol gasoline will give you more power and mileage. Since I started using 90 octane non ethanol unleaded gasoline my fuel mileage has gone up 8 to 10% and my truck noticeably produces more power.

Im a retired HVAC guy and had 2 to 3 chainsaws on the job site, and using ethanol gas on small engines was taboo and was detrimental to their health.

 

[Rockcrawlindude]

More important than straight up octane is running non ethanol gasoline. Gasoline is more energy dense than alcohol so running non ethanol gasoline will give you more power and mileage. Since I started using 90 octane non ethanol unleaded gasoline my fuel mileage has gone up 8 to 10% and my truck noticeably produces more power.

Ethanol free is heckin expensive. ~30% more expensive at the pump isn’t worth 8-10% better mpg. It’s fairly common knowledge that the air fuel ratio of gas is close to 14:1 and e85 is 10:1 with e10 falling somewhere in between so it makes sense you burn more of it. I buy ethanol free for my 90s vehicles and my mower but it isn’t worth it on a daily driver