What fuel for 5.7

[securityguy]

I was responding to you both, neither of you is 100% right. For a start, pinging is very audible, and yes you can hear it with your ears. Secondly, if I can still detect pinging with 91 octane, and we know that pinging results in reduced performance, then it obviously follows that going to 93 octane will increase your performance. That gain in performance is not due to having more energy in the gas, but because it allows your engine to work at near optimum performance. Reducing the octane reduces the capability of your engine to perform optimally.

You are clearly missing the intent of my statements. Yes, I agree that pinging is audible and easily heard and never stated that it wasn't. Pinging DOES result in poorer performance and never stated it didn't. Increasing octane to eliminate ping and knock is what should be done as that is the only thing increasing octane levels will result in related to our trucks. The higher the octane, the less energy the fuel produces. I believe that we are using the term "performance" differently. A truck running well on 89 will see no increases in performance upgrading to 93. Pinging and knocking is a totally different story and need to be used in the proper context when discussing "performance". My post #244 still stands as 100% accurate.

 

[silver billet]

You are clearly missing the intent of my statements. Yes, I agree that pinging is audible and easily heard and never stated that it wasn't. Pinging DOES result in poorer performance and never stated it didn't. Increasing octane to eliminate ping and knock is what should be done as that is the only thing increasing octane levels will result in related to our trucks. The higher the octane, the less energy the fuel produces. I believe that we are using the term "performance" differently. A truck running well on 89 will see no increases in performance upgrading to 93. Pinging and knocking is a totally different story and need to be used in the proper context when discussing "performance". My post #244 still stands as 100% accurate.

A truck will not run as well on 89 vs 93. Pinging and knocking is not a different story, it's the whole point. It will ping, or the ECU will reduce timing without audible pinging, but timing will be reduced either way, in which case your engine is not running optimally. There are guys on youtube who have plugged into HP Tuning and data logged their hemi's ECU. You're definitely getting reduced performance (less power) on 89. And I still hear pinging while working it hard with 91 octane. It's not a stretch to imagine that there would be less pinging with 93 though I haven't logged or tested it.

 

[silver billet]

"Based on this, you should be running 91 or higher in your truck".

Direct quote from a guy who actually did some real tests and logged the results. Worth a watch. I definitely won't run < 91 while towing, but I do sometimes put in 89 during the winter when it's just getting groceries.

 

[securityguy]

A truck will not run as well on 89 vs 93. Pinging and knocking is not a different story, it's the whole point. It will ping, or the ECU will reduce timing without audible pinging, but timing will be reduced either way, in which case your engine is not running optimally. There are guys on youtube who have plugged into HP Tuning and data logged their hemi's ECU. You're definitely getting reduced performance (less power) on 89. And I still hear pinging while working it hard with 91 octane. It's not a stretch to imagine that there would be less pinging with 93 though I haven't logged or tested it.

Let's agree to disagree my friend. I have NEVER experienced ping or knock using a good quality 89. I am also not aware of the majority of our Forum members complaining about ping and knock when using 89. The manufacturer RECOMMENDS 89 and nothing higher is required. Our trucks will run just as well on 89 as they will on 93...towing may be a different story. If you are not experiencing ping or knock, going to a higher octane is only a waste of money unless, as some stated, they can buy 93 for the price of 87-89 at Costco.

 

[silver billet]

Let's agree to disagree my friend. I have NEVER experienced ping or knock using a good quality 89. I am also not aware of the majority of our Forum members complaining about ping and knock when using 89. The manufacturer RECOMMENDS 89 and nothing higher is required. Our trucks will run just as well on 89 as they will on 93...towing may be a different story. If you are not experiencing ping or knock, going to a higher octane is only a waste of money unless, as some stated, they can buy 93 for the price of 87-89 at Costco.

Audible pinging only happens when it gets really bad. Unless you're logging your ECU, you can't state unequivocally that your truck is not pulling timing. Towing is just an example of stress, your engine might be stressed just as bad under high revs (but average speed) going up a mountain or steep hill. And if it's pulling timing, you're getting less MPG as well.

So it's very inaccurate to state that "our trucks will run just as well on 89 as they will on 93". You qualified it, this time, by saying "maybe if you're towing...". But that's the whole point. The more you work your truck, by hard accelerations or towing etc, the more important the octane is.

I would agree that 89 is probably sufficient for daily driving, but sufficient doesn't mean "no difference". It just means you can get away with it.

 

[Willwork4truck]

I have been running 87 octane in my 2020 and it runs fine when empty, but when you put a trailer behind it the trucks pings like a small block chevy. So i tried going to 91 octane and ping goes away. I have also found that the Costco 87 octane creates ping no matter what.

Our Costco only has 87 or 93, so I mix when I can. The other non-top tier stations around me have “89” but the hemi stills pings with their fuel (though not quite as bad as the UTube video example).
Not sure what to do about it other than just be easy on accelerating, or spend more money on premium more often. I definitely don’t like hearing the pinging when it is running down the highway and I gently accelerate to pass someone. If I were to tow or have big grades (as in Colorado) it would be using 91/93 all the way.
I want this engine to last and won’t skimp on fuel octane/prices if that’s the way it has to be. There’s enough discussion on this forum about the “hemi tick” and other inherent hemi ”issues” that I don’t want to add anything else by being too cheap on fuel.

 

[Amerinamese]

I just filled up for the first time this past Tuesday. I ended up putting 93 octane in at Costco because it was a .10 a gallon cheaper than any 89 octane in the area.

 

[Burnzie]

The only 89 octane around here is E15 and I don't want to put that in.

 

[Timeless]

The only 89 octane around here is E15 and I don't want to put that in.

Won't hurt anything. All modern vehicles (last 10+ years) are designed to run with pure gasoline up to E15.

 

[sppb32]

I did allot of engine work on my 04 including porting and milling the heads 0.020 to increase compression, well i had to run 93 octane and a tune for 87 that's so much timing the ECU was pulling, under load, this engines do run on the edge but if you're not towing or racing you are fine with 87

 

[5thGenLoco]

I have run both 87 and 89 and took note of the differences.
The 89 and 87 produced the same mpg with mixed driving.
The 89 produced around 1.5 mpg better on pure hwy driving.
The 89 "felt" more responsive overall and less "laggy" at low speeds.
Never experienced any pre-detonation (knock/ping) with either octane.
Driving has been from close to sea level up to 7k or so above.

If anyone is experiencing pre-det, they should have their truck looked at. The ECU should account for pre-det and adjust accordingly.

 

[silver billet]

If anyone is experiencing pre-det, they should have their truck looked at. The ECU should account for pre-det and adjust accordingly.

Unless it's really really bad, they're not going to do anything about it as Ram says (paraphrasing) "a small amount of pinging is normal". Who gets to define "small"? In my truck it doesn't get that bad unless I'm pulling a trailer up a hill at 3500+ rpms in the middle of summer on 89 or less.

The computer will pull timing on lower octanes, whether you hear pinging or not. So simply using your ear is not enough. You may be losing MPG and power whether you hear pinging or not, only a data log will tell you the truth. Maybe it's confirmation bias, but my truck runs far better on 91 and feels very lethargic on 87. I don't always hearing pinging on 87 (unless I'm working it hard).

 

[RAM Patriot]

To poke the bear if you will.

Slight ethanol(normal %) and high octane mix isn’t a bad thing.

I’m just going to leave this here....
and sit at the table with sign that says change my mind lol

Pure ethanol has a high octane number (99), but an energy density that is 32.5% lower than gasoline. This means that adding ethanol in any proportion to regular gasoline will increase the octane number, but will lower the fuel economy. This might seem contradictory because most people believe that high octane fuels will give them a higher fuel economy (measured as miles per gallon). Octane rating, however, is not a measure of the energy content of the fuel, but instead is a measure of its ability to burn at high compression ratios without auto-igniting.

One US gallon of gasoline contains 114,000 BTU of energy; depending on the time of year, and depending on what is in the gasoline. It is getting harder to find gasoline's that does not contain 5 to 10% of Ethanol.

Ethanol is ethyl alcohol; the kind of alcohol in beverages; beer, whiskey, bourbon, vodka, ****tails, etc.. It takes one and a half US gallons of ethanol to equal the energy in one US gallon of gasoline; the reason... because ethanol only has 76,100 BTU's of energy per gallon.

Less energy means less miles per gallon.

Gasoline's blended with Ethanol will lower MPG in most engines. The EPA says Fuel efficiency can decrease by 1.5% to 3%.

It is the BTUs that allows us to get the best fuel economy. Adding alcohol, of any kind, to gasoline, dilutes the fuel and lowers the heat energy.

Blends of alcohols can be tested to determine what is called a “Blending Octane Value” or BOV. Basically, the octane rating of an alcohol/gasoline blend is compared to the octane rating of the gasoline without alcohol and some math is done to calculate what the effect of the alcohol was on the octane of the gasoline. Thus, a BOV is determined. However, a BOV is not the same thing as a normal octane rating.

Octane numbers at the pump are determined by taking the average of two ASTM-specified octane tests – the Research Octane Number test (RON, or simply “R”) and the Motor Octane Number test (MON, or simply “M”). The average is expressed as (R+M)/2 and is sometimes referred to as the Antiknock Index or AKI. In the United States, pump gas is sold based on AKI and it is this value that we typically use to represent a fuel’s octane rating. The square yellow octane stickers you see on gasoline dispensers indicate the (R+M)/2 octane rating.

BOVs for methanol and ethanol typically overstate octane. This is because the law of diminishing returns applies. While a little alcohol can bump octane by a few numbers, twice as much alcohol does not result in twice as much octane increase. So while it may look like an alcohol has a high octane number when a small amount is used (as in determining a BOV), its real octane value is not as high. Problem is, the real number can’t be determined… so we’re left to guessing.

 

[Lake Ram]

I have never gotten much better than 19.5 mpg using 89 . My truck runs great on 89. 91 octane at COSTCO was 25 cents less than the cheapest 89 in my area. I was surpised what a difference it made considering the comments I read from people saying it makes no difference. It made a huge difference in my truck and I saved $7.00 on the tank over buying 89.

 

[LakesAZ]

I have never gotten much better than 19.5 mpg using 89 View attachment 72799. My truck runs great on 89. 91 octane at COSTCO was 25 cents less than the cheapest 89 in my area. I was surpised what a difference it made considering the comments I read from people saying it makes no difference. It made a huge difference in my truck and I saved $7.00 on the tank over buying 89. View attachment 72799

Nice! Crusing down I-10? The best part about Costco is you get a 4% cash back on gas purchases. So if gas is $2 a gallon at the pump, you end up paying $1.92!

 

[Scram1500]

I get 93 because I can't find 94

 

[smashweights]

87 for the last year/8k miles. Getting 16/23 mpg. Runs great. YMMV

 

[LakesAZ]

I get 93 because I can't find 94

We only get 91 here in Arizona

 

[Lake Ram]

Nice! Crusing down I-10? The best part about Costco is you get a 4% cash back on gas purchases. So if gas is $2 a gallon at the pump, you end up paying $1.92!

The 10, the 60, 101 and 202. Great freeway system here!

 

[SD Rebel]

I have never gotten much better than 19.5 mpg using 89 View attachment 72799. My truck runs great on 89. 91 octane at COSTCO was 25 cents less than the cheapest 89 in my area. I was surpised what a difference it made considering the comments I read from people saying it makes no difference. It made a huge difference in my truck and I saved $7.00 on the tank over buying 89. View attachment 72799

Big believer in Costco 91 octane, it meets our requirements, Top Tier while also being cheaper than most regular stations 87. If I couldn't get that, I would get ARCO 89 octane, still Top Tier.