Poor gas mileage

[GM26J]

Just for the fun of it I filled up this last tank with 89 octane instead of 87. Mileage went from the usual 17.4 to 19.5. That would be a theoretical extra 54.6 miles per tank or 2.8 gallons saved. At 3.70/gal, that's $10.36 saved at an extra fill-up cost of $5.60

Hard to believe it could make that much of a difference but I'll try a few more tanks to see if this holds up.

 

[Rgerhardt]

Looking at a 2022 Limited with 3.92 and now reading these posts I’m concerned that my milage may suck if I purchase it. I’m coming from a 2014 Sport that will get 20+ on the freeway.

 

[BowDown]

Just for the fun of it I filled up this last tank with 89 octane instead of 87. Mileage went from the usual 17.4 to 19.5. That would be a theoretical extra 54.6 miles per tank or 2.8 gallons saved. At 3.70/gal, that's $10.36 saved at an extra fill-up cost of $5.60

Hard to believe it could make that much of a difference but I'll try a few more tanks to see if this holds up.

I believe you. I posted similar about a year ago and people said no way. 89 octane does improve fuel mileage and if you think about it, it's easy to see why.
87 will ping, (a lot pinging is inaudible in the cab) and pull timing, pulling timing reduces torque, reduction in torque means you turn more RPM to make the same power needed to accelerate or maintain a speed, more RPM = more fuel.
My previous truck was 1.5-2mpg different on the highway and about 25-30 miles less per tank than running 89.

I use 93 in this truck for 2 reasons,
1, I fuel up at Costco and they only have 87 and 93. Costco's 93 is usually cheaper than every other stations 89.
2, I initially wanted to use 93 in the summer for the extra protection from detonation/pinging and was going to switch to 89 once it cooled off. That changed when I started getting gas at Costco because of their pricing and top tier fuel

 

[ferraiolo1]

My last 1500 mile weekend trip, I tried e88, 87, and 89. Each tank got almost the exact same mileage.

88 and 89 had virtually no pinging when downshifting going up mountains. I won’t run 87 simply for that. And 88 is cheaper than 87.

93 is usually $0.50 more a gallon around here. So that’s not even worth it.


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[Mountain Whiskey]

Just for the fun of it I filled up this last tank with 89 octane instead of 87. Mileage went from the usual 17.4 to 19.5. That would be a theoretical extra 54.6 miles per tank or 2.8 gallons saved. At 3.70/gal, that's $10.36 saved at an extra fill-up cost of $5.60

Hard to believe it could make that much of a difference but I'll try a few more tanks to see if this holds up.

A 12% increase huh? You sir, have what is known as a unicorn vehicle.

Car and Driver did a good article titled "Is Premium Gas Worth It?" It compared a bunch of different vehicles in both dyno testing and actual real world results.

It began explaining something about octane:

"Raising the octane rating (also known as the anti-knock index) doesn't change the energy content of a gallon of gasoline. A higher octane rating indicates greater resistance to knock, the early combustion of the fuel-air mixture that causes cylinder pressure to spike. When higher-octane fuel is flowing through its injectors, the engine controller can take advantage of the elevated knock threshold and dial in more aggressive timing and higher boost pressures to improve performance."

It ran through many cars and trucks with similar results. It did not have a Ram 5.7 but did have a Charger 5.7. The article stated:

"Saddled with elephantine heft and eager to spin its rear all-season tires at launch, the Charger posted the same 4.9-second hustle to 60 mph on 87 and 93 octane. At triple-digit speeds, the higher power on 93 octane gave the Charger an advantage measured in tenths of a second. The Dodge also posted a 0.3-mpg improvement on premium with its average of 23.5 mpg. Just as important, the bellicose roar of the iron-block Hemi and the Charger's ability to reduce its rear tires to jungle-gym ground cover are unaffected by the fuel in the tank.

While Ford's EcoBoost F-150 stands out as an obvious exception, the Dodge Charger's numbers make for a tidy summary of our findings. If you buy fuel with an octane rating above the manufacturer's requirement, you're likely to feel it in your wallet more than the seat of your pants."

The posted results for the test vehicles. Notably the Hemi was almost unfazed by the difference in gas grades. No faster 0-60, a couple tenths in a quarter mile and 2 tenths of a mile per gallon.



Don't sell that unicorn. They are very rare. Jay Leno might be giving you a call.

 

[GM26J]

A 12% increase huh? You sir, have what is known as a unicorn vehicle.

Car and Driver did a good article titled "Is Premium Gas Worth It?" It compared a bunch of different vehicles in both dyno testing and actual real world results.

It began explaining something about octane:

"Raising the octane rating (also known as the anti-knock index) doesn't change the energy content of a gallon of gasoline. A higher octane rating indicates greater resistance to knock, the early combustion of the fuel-air mixture that causes cylinder pressure to spike. When higher-octane fuel is flowing through its injectors, the engine controller can take advantage of the elevated knock threshold and dial in more aggressive timing and higher boost pressures to improve performance."

It ran through many cars and trucks with similar results. It did not have a Ram 5.7 but did have a Charger 5.7. The article stated:

"Saddled with elephantine heft and eager to spin its rear all-season tires at launch, the Charger posted the same 4.9-second hustle to 60 mph on 87 and 93 octane. At triple-digit speeds, the higher power on 93 octane gave the Charger an advantage measured in tenths of a second. The Dodge also posted a 0.3-mpg improvement on premium with its average of 23.5 mpg. Just as important, the bellicose roar of the iron-block Hemi and the Charger's ability to reduce its rear tires to jungle-gym ground cover are unaffected by the fuel in the tank.

While Ford's EcoBoost F-150 stands out as an obvious exception, the Dodge Charger's numbers make for a tidy summary of our findings. If you buy fuel with an octane rating above the manufacturer's requirement, you're likely to feel it in your wallet more than the seat of your pants."

The posted results for the test vehicles. Notably the Hemi was almost unfazed by the difference in gas grades. No faster 0-60, a couple tenths in a quarter mile and 2 tenths of a mile per gallon.
View attachment 111286


Don't sell that unicorn. They are very rare. Jay Leno might be giving yo

Hard to compare as C&D always beats on their test cars pretty hard, lol. Less detonation means the ECU can adjust timing - that can yield more power or more mileage. I'm just reading the mpg off the dash display when I reset at each fill up.

Keep in mind that fuel additives can also greatly affect mileage. I know here in Massachu$etts they always put an additive into the gas for the winter and it has the effect of reducing mileage pretty significantly. The practice seems to vary around the country. I'm guessing there's also some variation between brands but that's really hard to know. I see all the same fuel trucks going to the same fuel farm to fill up, so who knows?

 

[Timeless]

Looking at a 2022 Limited with 3.92 and now reading these posts I’m concerned that my milage may suck if I purchase it. I’m coming from a 2014 Sport that will get 20+ on the freeway.

Luckily you have time to change it to the 3.21 if you are concerned.

 

[IvoryHemi]

Looking at a 2022 Limited with 3.92 and now reading these posts I’m concerned that my milage may suck if I purchase it. I’m coming from a 2014 Sport that will get 20+ on the freeway.

Don’t sweat it. The mpg 3.21/3.92 gear argument is overblown. There is minimal difference

 

[BowDown]

A 12% increase huh? You sir, have what is known as a unicorn vehicle.

Car and Driver did a good article titled "Is Premium Gas Worth It?" It compared a bunch of different vehicles in both dyno testing and actual real world results.

It began explaining something about octane:

"Raising the octane rating (also known as the anti-knock index) doesn't change the energy content of a gallon of gasoline. A higher octane rating indicates greater resistance to knock, the early combustion of the fuel-air mixture that causes cylinder pressure to spike. When higher-octane fuel is flowing through its injectors, the engine controller can take advantage of the elevated knock threshold and dial in more aggressive timing and higher boost pressures to improve performance."

It ran through many cars and trucks with similar results. It did not have a Ram 5.7 but did have a Charger 5.7. The article stated:

"Saddled with elephantine heft and eager to spin its rear all-season tires at launch, the Charger posted the same 4.9-second hustle to 60 mph on 87 and 93 octane. At triple-digit speeds, the higher power on 93 octane gave the Charger an advantage measured in tenths of a second. The Dodge also posted a 0.3-mpg improvement on premium with its average of 23.5 mpg. Just as important, the bellicose roar of the iron-block Hemi and the Charger's ability to reduce its rear tires to jungle-gym ground cover are unaffected by the fuel in the tank.

While Ford's EcoBoost F-150 stands out as an obvious exception, the Dodge Charger's numbers make for a tidy summary of our findings. If you buy fuel with an octane rating above the manufacturer's requirement, you're likely to feel it in your wallet more than the seat of your pants."

The posted results for the test vehicles. Notably the Hemi was almost unfazed by the difference in gas grades. No faster 0-60, a couple tenths in a quarter mile and 2 tenths of a mile per gallon.
View attachment 111286


Don't sell that unicorn. They are very rare. Jay Leno might be giving you a call.

Motor trend and Cans D aren't the most reliable sources, they did get busted faking dyno numbers not too long ago.

That said, it's not about making more power with higher octane, it's about not losing power. It's a fact that pinging/detonation cause a power loss by the PCM pulling ignition timing. It's also a fact that pulling ignition timing reduces power output at a given RPM.

It's not unreasonable to see mpg gains from reducing or eliminating knock retard, especially in southern climates when it's hot.

 

[BowDown]

Looking at a 2022 Limited with 3.92 and now reading these posts I’m concerned that my milage may suck if I purchase it. I’m coming from a 2014 Sport that will get 20+ on the freeway.

Go rent one and live with it for a few days to see. Luckily or unluckily my wife's car was in the shop for some minor paint work and the rental was a 2019 Ram Laramie with a 3.21 gear. We had it for a week which I drove it to compare to my 3.92 gen 3 and to see if I liked the truck before I bought it.

Initially I thought thelis truck was a 3.92 due to the way it performed, 18" wheels and would burn the tires off from a stop sign. The window sticker was in the glove compartment and to my surprise, it had 3.21 gears.

Between the performance of the truck and the fuel mileage, that sold me on looking for a truck with a 3.21 gear.

If you can find one of both, I would test them out for a few days and see how you like it that way you'll have no regrets

 

[sessman]

I have a 2021 RAM w/ 5.7 (non etorque) 4x4, 3.92, w/ 1900 miles on it. I am currently averaging 12.5 mpg with gentle driving (about 80% city / 20% hwy) using 89 octane only.

Is this normal? Will it get better after the break in period?

 

[sessman]

Did some city driving last weekend. NYC metro area. I got around 10mpg And there wasn't that much traffic. The stop and go from traffic lights really kills the mpg.

I think this answered my question, primarily city driving - 12.5 mpg seems normal

 

[Scram1500]

I have a 2021 RAM w/ 5.7 (non etorque) 4x4, 3.92, w/ 1900 miles on it. I am currently averaging 12.5 mpg with gentle driving (about 80% city / 20% hwy) using 89 octane only.

Is this normal? Will it get better after the break in period?

Be less gentle, you'll spend less time accelerating while the transmission is making those long, lazy comfortable shifts. If you give it more gas the converter locks up sooner and less energy is lost through the slush box

 

[Jako]

I think this answered my question, primarily city driving - 12.5 mpg seems normal

Based on my experience that is about right. Cold weather (cold motor, winter gas) will also decrease your mpg, short trips on a cold day will hurt the mpg. Without doing any research and calculations I would say 10%+ for me.

 

[bigdodge]

I use 93 in this truck for 2 reasons,
1, I fuel up at Costco and they only have 87 and 93. Costco's 93 is usually cheaper than every other stations 89.
2, I initially wanted to use 93 in the summer for the extra protection from detonation/pinging and was going to switch to 89 once it cooled off. That changed when I started getting gas at Costco because of their pricing and top tier fuel

have you ever considered doing half 87 and half 93 at costco?

I did it years ago for a different vehicle and had no pinging

 

[BowDown]

have you ever considered doing half 87 and half 93 at costco?

I did it years ago for a different vehicle and had no pinging

That may be an option, gonna p**s off all the people in line behind me though

 

[BowDown]

I think this answered my question, primarily city driving - 12.5 mpg seems normal

I'm 16-17 ish just city driving

 

[Jako]

That may be an option, gonna p**s off all the people in line behind me though

I do 1/3 93 followed by 2/3 87 and still faster than some of the day dreamers and mopes.
Need to get some "cya training" so I don't break the law in NJ if I pump my own.

Here's Why Some Places In The U.S. Still Won't Let You Pump Your Own Gas

Here’s why New Jersey and some parts of Oregon have weirdly strict gas pump rules.

jalopnik.com

 

[sessman]

I'm 16-17 ish just city driving

Yeah you have 3.21 and 4x2 which may be the reason for the difference...

 

[Idahoktm]

Yeah you have 3.21 and 4x2 which may be the reason for the difference...

Maybe a little bit, but I get the same mileage as he gets with a 3.92 4x4.