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89 octane recommend, does it really make a difference?

I use your method of filling with 91 octane, drive down to nearly half a tank, then fill with 87.

I wouldn't dare try that in one sitting unless for some rare occasion no one is behind me in line. On a busy day, the person behind you is making sure you don't take too long putting your pin in the card reader, I can't imagine what would happen if I tried to fill up with two different octanes, lol :)
True and at my Costco it is always busy as it is the only one for almost 100 miles. That and trying to fill my 33 gallon tank using two different octanes would take awhile.
 
I use your method of filling with 91 octane, drive down to nearly half a tank, then fill with 87.

I wouldn't dare try that in one sitting unless for some rare occasion no one is behind me in line. On a busy day, the person behind you is making sure you don't take too long putting your pin in the card reader, I can't imagine what would happen if I tried to fill up with two different octanes, lol :)

Not at Costco, but I used to mix 93 and E85 to get E50 when I was pushing the limits on my ecoboost. That was always an adventure...
 
Our HEMI engines are optimized to run on 89 octane fuel.

If your ECM can advanced the timing enough to take advantage of 93 octane fuel or if you are running a tune on your truck that is optimized for high octane fuel than I would agree that your truck would get better gas mileage from the 93 octane fuel. Otherwise, you will be wasting a huge amount of money paying for high octane gasoline.
I agree. My disagreement is that it would get worse mileage. It should get the same.
 
I agree. My disagreement is that it would get worse mileage. It should get the same.
Using a higher-octane fuel allows an engine to take advantage of an ideal timing curve without causing detonation. Once that timing has been achieved, there is no advantage to using higher-octane fuel.
 
I have 2 choices at most places I get gas. 87 or 87. Although it does say a minimum of 87. One is ethanol blended, (cheaper), and the other is not. This station has 8 pumps, and is just off 2 major highways. I drive past it multiple times a day, and always at least 4 of the pumps, if not all 8 are being used.
88e0e2e3f89db9561e0bbef5dfa599d1.jpg


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I have 2 choices at most places I get gas. 87 or 87. Although it does say a minimum of 87. One is ethanol blended, (cheaper), and the other is not. This station has 8 pumps, and is just off 2 major highways. I drive past it multiple times a day, and always at least 4 of the pumps, if not all 8 are being used.
88e0e2e3f89db9561e0bbef5dfa599d1.jpg


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I suggest you find an App for you phone like GasBuddy or Pure Gas to find other options.
 
I have 2 choices at most places I get gas. 87 or 87. Although it does say a minimum of 87. One is ethanol blended, (cheaper), and the other is not. This station has 8 pumps, and is just off 2 major highways. I drive past it multiple times a day, and always at least 4 of the pumps, if not all 8 are being used.
88e0e2e3f89db9561e0bbef5dfa599d1.jpg


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Where is this at as I might have to stop the next time I'm driving through Iowa. 🤣
 
Communist? North Korea?
what do you mean you cant fuel your
own truck up?


I live in Oregon where we can't fuel are own vehicles. I noticed yesterday the genius who filled me up used 87 when I asked for 89. Guess I'll find out if there is any difference.
 
Oregon and I believe New Jersey have laws that require a gas attendant to fuel your vehicle. I'm not sure the reason the law still exists.
Correct on NJ, but I still pump my own, only had an issue once at a south NJ Costco, new guy I think. I ride motorcycles and I doubt there are many riders that allow the attendant to pump the gas.

Helps the NJ employment numbers??????????
NY has another theory for employment, well at least for "undocumented/illegals"
 
Using a higher-octane fuel allows an engine to take advantage of an ideal timing curve without causing detonation. Once that timing has been achieved, there is no advantage to using higher-octane fuel.
Again...I do not disagree. However someone said you get worse gas mileage from 93 premium.

My response is that it should be the same as 89.
 
I use your method of filling with 91 octane, drive down to nearly half a tank, then fill with 87.

I wouldn't dare try that in one sitting unless for some rare occasion no one is behind me in line. On a busy day, the person behind you is making sure you don't take too long putting your pin in the card reader, I can't imagine what would happen if I tried to fill up with two different octanes, lol :)
It adds 15 seconds to the process if you are quick about it and use tap-to-pay on a Costco Visa card. I couldn't give a **** less what the person behind me thinks. If they're mad, tell them to call Costco and request they implement a mid-grade button. Going to the station 2x as often (because you're treating 1/2 a tank as your empty mark) is a huge waste of time.
 
It adds 15 seconds to the process if you are quick about it and use tap-to-pay on a Costco Visa card. I couldn't give a **** less what the person behind me thinks. If they're mad, tell them to call Costco and request they implement a mid-grade button. Going to the station 2x as often (because you're treating 1/2 a tank as your empty mark) is a huge waste of time.
I do the 1/3 - 2/3 method as the Costcos in my area have 87 and 93. The Staten Island Costco has an optimum location, long wait with older machines and NYC laws limiting the length of the nozzle gas hose, so you can only fill up from one side of the pump. Anybody using this Costco who expects a quick fill up is fooling themselves and probably are amusing themselves with their phone. I'm the least cause of time used when filling up. Amazing how many are just pulling out their credit card and figuring out how the pump works.

The Bayonne Costco has updated machines with many more pumps, longer hoses (pump either side) and requires the employee to pump (NJ law) gas. I pump my own however and really do not take that much time switching blends. Probably save some time by pumping my own versus the single blend with attendant fill up.

Not that hard to do:
1. miles on the tank of gas/mpg = gallons to fill up
2. gallons/3 = 87 octane gallons
3. gallons - 87 octane = 93 octane

I always pump the 93 octane first to get what is in the hose.
 
I feed my Hemi's (Ram and Jeep Overland) only the best.
And I do notice a bit more off the line response and better mileage, at least 2, maybe more.
 
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Using a higher-octane fuel allows an engine to take advantage of an ideal timing curve without causing detonation. Once that timing has been achieved, there is no advantage to using higher-octane fuel.
Engine Master's on Motortrend just did a study on 87,91,106,116,E-85 fuels on a 10.5 compression hi HP engine and this was exactly their findings. As long as the engine can attain it's optimum timing without pinging, there was no difference in performance.
Engine made 499 torque 540 HP during the test.
 
Again...I do not disagree. However someone said you get worse gas mileage from 93 premium.

My response is that it should be the same as 89.
Why would it be the same? If you understand what the octane number means, and how different octane levels react, you would understand. Granted the normal person may not see enough of a difference to notice, but there is a difference.
 
Why would it be the same? If you understand what the octane number means, and how different octane levels react, you would understand. Granted the normal person may not see enough of a difference to notice, but there is a difference.
Because the fuel value of the gasoline doesn't change with octane level. So if the engine can achieve it's preferred timing curve without pinging it will burn the all of them the same resulting in the same numbers.
 

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