Advice Requested: Octane 93 vs. 91

[Ambitious1]

I would like to ask everyone's advice. There may be an old thread that covers this subject, but I couldn't find it. I am aware that the MM's recommended fuel is premium 91 octane. I have always gone to the local gas station which offers 93 octane with 10% ethanol. A new gas station has opened nearby which offers 91 octane with no ethanol.

Which one would be better for engine longevity for a daily driving, non-racing application? 93 octane with 10% ethanol or 91 octane non-ethanol? Does the ethanol make a difference? Positive or negative effects? I am not concerned about the price of the fuel, but rather the best fuel I can buy for my MM. Thank you in advance.

[NorthShoreChiMM]

Ethanol burns "cooler" but it takes much more of it to produce the same power you would get with gasoline. You might get marginally better mpg with the straight 91 but not enough you would notice. Buying good quality fuel with good additives is much more important, (just my take on it, please correct me if I'm wrong)

[BLACKMARAUDER04]

Out her in California, we only get 91 octane.
All Fuel is made with upto 10% Ethanol
Minimum octane ratings are made be each state. For example, Premium in California is 91, Georgia is 93.


https://en.wikipedia.org/wiki/U.S._State_Fuel_Octane_Standar ds

[MyBlackBeasts]

I would like to ask everyone's advice. There may be an old thread that covers this subject, but I couldn't find it. I am aware that the MM's recommended fuel is premium 91 octane. I have always gone to the local gas station which offers 93 octane with 10% ethanol. A new gas station has opened nearby which offers 91 octane with no ethanol.

Which one would be better for engine longevity for a daily driving, non-racing application? 93 octane with 10% ethanol or 91 octane non-ethanol? Does the ethanol make a difference? Positive or negative effects? I am not concerned about the price of the fuel, but rather the best fuel I can buy for my MM. Thank you in advance.


91 w/o will give you more power and better mpg, try it and see if you get any pinging.


All we have around me is 91 and most stations it is w/o crapanol. No problems in 6 years.


I also throw a can of Race Gas in too.

[Gryphonzus]

Plus it doesn't gum stuff up like Ethanol does. I have had more carburators and fuel lines messed up because of that junk.

[Invective]

I would like to ask everyone's advice. There may be an old thread that covers this subject, but I couldn't find it. I am aware that the MM's recommended fuel is premium 91 octane. I have always gone to the local gas station which offers 93 octane with 10% ethanol. A new gas station has opened nearby which offers 91 octane with no ethanol.

Which one would be better for engine longevity for a daily driving, non-racing application? 93 octane with 10% ethanol or 91 octane non-ethanol? Does the ethanol make a difference? Positive or negative effects? I am not concerned about the price of the fuel, but rather the best fuel I can buy for my MM. Thank you in advance.

You didn't state whether your car is stock or not. Stock tune? 91 E0 will be fine. I use 93 E0 in my Marauder and Mustang due to the 93 octane custom tunes they have. My bikes run fine on the recommended 90 E0 and my pickup truck runs fine on the recommended 87 E0. The difference is most pronounced in my pickup as it lets me know right away that it just flat loves E0 with idle and throttle response noticeably improved.

Fuel mileage? 5 - 20% improvements often reported. My unscientific method is the trip to my daughter's home is approx. 120 miles away, primarily interstate highway. Both the Mustang and Ranger would burn nearly a half a tank of E10 while barely burning a quarter of a tank of E0.

The jury is still out on the Marauder as I've pretty much burned E0 since I brought it home last spring and received numerous upgrades from MartyO's shop this past August. Fuel mileage took a dump right after MartyO messaged it but has gotten noticeably better since the IAC valve and both the fuel vapor control solenoid and fuel vapor vent valve were replaced last month.:beatnik:

[Mr. Man]

The Marauder is to run on premium. 91 octane is the minimum, but the stock tune can handle 93. To get the maximum performance the tune needs to be adjusted to the specific octane.
Keep in mind if the pump says 91 octane that is the minimum it can legally be. It probably is as close to 91 as the suppliers can make it , but it is possible it might be higher.

I'm not sure if the owners manual says anything about e-85 , but you might want to at least see if it says anything.

[MyBlackBeasts]

The Marauder is to run on premium. 91 octane is the minimum, but the stock tune can handle 93. To get the maximum performance the tune needs to be adjusted to the specific octane.
Keep in mind if the pump says 91 octane that is the minimum it can legally be. It probably is as close to 91 as the suppliers can make it , but it is possible it might be higher.

I'm not sure if the owners manual says anything about e-85 , but you might want to at least see if it says anything.


The stock Marauder is not a Flex-Fuel vehicle.


Not only will it not run well on E85, E85 will cause destruction to the fuel system components an eventually the engine.


Do not run E85 in a marauder that has not been completely re-engineered to do so.