Quickest and safest way to go from 87 Octane to 91 Octane

[Capricorn]

As I posted on a previous thread, I got a new 2019 JLUR 2.0.
The dealer filled it up with regular 87 octane gas.
What is the best option to quickly get to 91 octane?

1. Drive around and every couple of days pump 91 octane and eventually the full tank will be 91 octane?
2. Drive around till the tank is nearly empty, and then fill the whole tank with 91 octane?

And here is a third option which may be the quickest but I want to know if it is safe to do so:
In Las Vegas, some pumps sell 100 octane. If my tank is 80% full with 89 octane, and if I add 1 gallon or so with 100 octane, (don't worry about the exact quantity - I can come up with the math to get to 91 octane), would that work? And then susequent/future fill ups can be 91 octane.

Sponsored

 

[Krondor]

2

What's the hurry?

 

[Capricorn]

My hurry? It is a shiny new toy, 91 is recommended for it, and I would like to drive it as the way it should as soon as possible.

 

[blnewt]

Just fill when you want w/ 91, engine will adjust for the lower octane in the meantime, enjoy your new JL!

 

[Chocolate Thunder]

No harm from using up the 87. Use it all then fill with the 91 you want to use.

 

[Demonic]

87 is fine for it. If you're heading to the drag strip you may be a few hp down because the engine will adjust the timing for it, but I have a feeling that's not your concern.

 

[ormandj]

Just fill like you normally would. Once you've run through a tank or two you'll be running higher octane. Or, just fill up with 93/100 or whatever else it is you have around there, and you'll get there sooner. 'Too much' octane won't hurt a thing, you'll just get worse gas mileage, as the fuel is less energy dense, it just resists knock better.

 

[Capricorn]

Just fill like you normally would. Once you've run through a tank or two you'll be running higher octane. Or, just fill up with 93/100 or whatever else it is you have around there, and you'll get there sooner. 'Too much' octane won't hurt a thing, you'll just get worse gas mileage, as the fuel is less energy dense, it just resists knock better.

I happen to have a Rebel Gas Station just a mile down the street from my home. They have 100 Octane Oxygenated Unleaded fuel. I am wondering if "Oxygenated" may mean too much Ethanol maybe? If I fill a couple of gallons of 100, I will reach 91 immediately. But is there any risk?
Or is there more risk in driving with 87 with some carbon deposits while I reach 91?

 

[ormandj]

87 doesn't lead to a bunch of additional carbon deposits. The additive package in the fuel (if at a top tier gas station, it's all around the same. I prefer Shell/Chevron) is what deals with that. Your ECU is just pulling timing to keep the knock down while running on lower octane, impacting your performance. Just start filling with 91 or 93 or whatever normal fuel you have there and you'll be fine. Don't go get race gas (that oxygenated 100 octane is almost surely race fuel), it won't have the additives you want, and it generally isn't nearly as stable.

 

[Capricorn]

87 doesn't lead to a bunch of additional carbon deposits. The additive package in the fuel (if at a top tier gas station, it's all around the same. I prefer Shell/Chevron) is what deals with that. Your ECU is just pulling timing to keep the knock down while running on lower octane, impacting your performance. Just start filling with 91 or 93 or whatever normal fuel you have there and you'll be fine. Don't go get race gas (that oxygenated 100 octane is almost surely race fuel), it won't have the additives you want, and it generally isn't nearly as stable.

Awesome - thanks. Yes, I also stick to Shell because of their Fuel Rewards, and Chevron as my second.

 

[blnewt]

Costco has great gas too, and nice prices

 

[Capricorn]

Costco has great gas too, and nice prices

True.

 

[rustyshakelford]

I’ve read this thread 3 times and still cannot determine if you’re being sarcastic or serious. If serious, can we count on your to do a full fluid change at 100, 500 and 1000 miles?

Brett

 

[Avar928]

Jeep recommends using premium grade but it's not a necessity and many owners are fine filling up using regular so you can mix-match or just dump in after near empty, doesn't matter it's all safe. The ECU will prevent knocking, and you'll have slightly decreased performance (power and MPG) but that's it.

 

[Goin2drt]

Also not sure if this is sarcastic. If it is not, STOP WORRYING, go drive your Jeep. Fill it up whenever your heart desires. You will do NOTHING to harm your vehicle. Worse case scenario in about 40K miles you might get some knocking from using 87 octane. Again nothing will harm the engine.

Sponsored