In Indiana, we use 87 octane gas in our JGC, with the 4.0L. When we get out to Colorado for our vacation, can we use the 85 octane without causing any problems?

Any advantages/disadvantages we should be aware of?

See excerpt from the Manual below:


FUEL REQUIREMENTS
GASOLINE ENGINES
Your vehicle is designed to meet all emission regulations and provide excellent fuel economy when using high quality regular unleaded gasoline with an octane rating of 87. The use of premium gasoline is not recommended. The use of premium gasoline will provide no benefit over high quality regular gasolines, and in some circumstances, may result in poorer performance.
Light spark knock at low engine speeds is not harmful to your engine. However, continued heavy spark knock at high speeds can cause damage and immediate service is required.

Poor quality gasoline can cause problems such as hard starting, stalling and hesitations. If you experience these symptoms, try another brand of gasoline (with the appropriate octane rating for your engine) before considering
service for the vehicle.


Reformulated Gasoline
Many areas of the country require the use of cleaner burning gasoline referred to as “Reformulated Gasoline”. Reformulated gasolines contain oxygenates, and are specifically blended to reduce vehicle emissions and improve
air quality.

The manufacturer supports the use of reformulated gasolines. Properly blended reformulated gasolines will provide excellent performance and durability of engine and fuel system components.


Gasoline/Oxygenate Blends
Some fuel suppliers blend unleaded gasoline with oxygenates such as 10% ethanol, MTBE, and ETBE. Oxygenates are required in some areas of the country during the winter months to reduce carbon monoxide emissions.
Fuels blended with these oxygenates may be used in your vehicle.

CAUTION!
DO NOT use gasolines containing Methanol or E85 Ethanol. Use of these blends may result in starting and driveability problems and may damage critical
fuel system components.

Problems that result from using methanol/gasoline blends are not the responsibility of the manufacturer. While MTBE is an oxygenate made from Methanol, it does not have the negative effects of Methanol. MMT In Gasoline MMT is a manganese containing metallic additive that is blended into some gasoline to increase the octane number. Gasolines blended with MMT offer no performance advantage beyond gasolines of the same octane number without MMT. Gasolines blended with MMT have shown to reduce spark plug life and reduce emission system performance in some vehicles. The manufacturer recommends using gasolines without MMT. Since the MMT content of gasoline may not be indicated on the pump, you should ask your gasoline retailer whether or not his/her gasoline contains MMT.
It is even more important to look for gasolines without MMT in Canada, because MMT can be used at levels higher than those allowed in the United States.

MMT is prohibited in Federal and California reformulated gasolines.


Materials Added to Fuel
All gasoline sold in the United States is required to contain effective detergent additives. Use of additional detergents or other additives is not needed under normal conditions and would result in additional cost. Therefore you should not have to add anything to the fuel.

Fuel System Cautions
CAUTION!

Follow these guidelines to maintain your vehicle’s
performance:


The use of leaded gas is prohibited by Federal law. Using leaded gasoline can impair engine performance, damage the emission control system.

An out-of-tune engine, or certain fuel or ignition malfunctions, can cause the catalytic converter to overheat. If you notice a pungent burning odor or some light smoke, your engine may be out of tune or malfunctioning and may require immediate service. Contact your dealer for service assistance.

The use of fuel additives which are now being sold as octane enhancers is not recommended. Most of these products contain high concentrations of methanol. Fuel system damage or vehicle performance problems resulting from the use of such fuels or additives is not the responsibility of the manufacturer.


NOTE: Intentional tampering with emissions control systems can result in civil penalties being assessed against you.


Unique Engine Calibration
When the system has the 4WD lock lever engaged and is in the Low Off-Road mode or reverse, the engine calibration changes to run higher spark advance with premium fuel for optimum off-road performance. Your vehicle is equipped with an active spark knock system and can adjust the engine calibration for varying range of fuel octane levels.

NOTE: For optimum off-road performance, premium fuel is recommended. However, your vehicle is equipped with an active spark knock system and can
adjust the engine calibration for varying range of fuel octane levels.


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Carry a bottle of Rum 151 and pour an ounce or two in every tankful... should compensate for the 2 octane loss in Colorado...

:)

(just kidding... you can't buy 151 but I CAN!)

I had this same question when I was in CO. My brother said not to use it, but what if you don't have a choice?

* update

NVM, I've seen only the 85 stuff, not E85. But is that the same as the stuff that says 10% ethanol? I'm confused.

NVM, I've seen only the 85 stuff, not E85. But is that the same as the stuff that says 10% ethanol? I'm confused.

No. E85 is 85% ethanol, 15% conventional gasoline. As I'm sure you're aware, E85 is made from corn, while 85 Octane gasoline is a lower grade of gasoline. E85 is an alternative (flex) fuel, and using it in an engine not designed for it will ruin it. E85 can also be likened to biodiesel, such as B10 or B15, where the fuel contains 10/15% respectively of biodiesel and 90/85% regular "dino diesel."

Hopefully this helps. :smiley_thumbs_up:

Here in Indiana, E85 is prevelant at a lot of gas stations. We're one of the biggest suppliers of E85, flex fuel, in the US.

I would think you'd want to go higher in octane due to the higher elevation and thinner air to avoid ping. But to be honest, I don't know for sure.

I would think you'd want to go higher in octane due to the higher elevation and thinner air to avoid ping. But to be honest, I don't know for sure.


It is the opposite. The 85 octane regular unleaded gas is used because of the high altitude. There are few places in Colorado as low in elevation as 4,000 ft. And from the Front Range (just before the start of the Rocky Mountains) which would be a north/south line of Colorado Springs, Denver, FT Collins the elevations are 5,000 ft and even a lot more as you go west.

85 octane is all I use in the Patriot, and other vehicles. And I drive regularly in places as high as 9,000 ft to 12,000 ft.

But, as mentioned, E85 is not the same thing as the 85 octane regular gas sold here. Do not use E85.

Yes you can use 85 Octane in the Intermountain West. The higher the altitude the lower the requirement for octane. The manuals are written assuming evert one lives at sea level. If you doubt the facts, pay a little more if it gives you peace of mind. There has been so much confusion the stations are now offering 87octane along side the 85. Unfortunately, sorry corn farmers, the are boosting the octane with ethanol. More octane fewer mpg. I've been driving cars, trucks, motorcycles, boats, you name it on unleaded 85 octane every since they took the lead out and have never had a problem real or imagined.

No. E85 is 85% ethanol, 15% conventional gasoline. As I'm sure you're aware, E85 is made from corn, while 85 Octane gasoline is a lower grade of gasoline. E85 is an alternative (flex) fuel, and using it in an engine not designed for it will ruin it. E85 can also be likened to biodiesel, such as B10 or B15, where the fuel contains 10/15% respectively of biodiesel and 90/85% regular "dino diesel."

Hopefully this helps. :smiley_thumbs_up:

It's 85% gasoline and 15% ethanol.

Octane ratings are slightly different in UK . My 2.4 Avenger will run on Regular unleaded 95 Oct. & Premium unleaded 98Oct. I usually use 95 but occasionally give it a treat of 98Oct. I never see pumps in UK with a mention of Ethanol or any other silly additives & we dont have Winter grade fuel , its refined to a high standard & is the same year round. However the downside is , you have to take out a bank loan to fill the tank...lol !! I believe that some UK Fuel has a 5% Ethanol content , but its not advertised as such & nobodies really bothered!!

I'd like to know as well... My old Mitsubishi ran fine on 85 and using 87 when out of state, and so does my mom's truck. The altitude thing makes sense.

It's 85% gasoline and 15% ethanol.

http://en.wikipedia.org/wiki/E85

E85 is an abbreviation for an ethanol fuel blend of up to 85% denatured ethanol fuel and gasoline or other hydrocarbon (HC) by volume. E85 is commonly used by flex-fuel vehicles in the US, Canada, and Europe. Some of the benefits of E85 over conventional gasoline powered vehicles include the potential for localized production of fuel in agricultural areas. Another benefit is potentially reduced pollution emissions especially Carbon dioxide in Earth's atmosphere which is an important element for adaptation to global warming.

I would think on "new" cars with an anti knock sensor, you could burn 80 octane and still not have it ping. We used to do that on all our cars that wanted premium. Just listen for it to ping and then retard the timing a speck. Of course with new cars you can't fool with the timing.:doh: