[Thor]

Hi all, are we use to regular or the high grade gas in the GC 4xE - Manual says 87 but also 91 .

This engine is designed to meet all emission
87 requirements, and provide satisfactory fuel economy and performance, when using high-quality unleaded regular gasoline havin
an octane rating of 87, as specified by the (R+M)/ 2 method. The use of 91 or higher octane premium gasoline will allow these engines to operate to optimal performance.

 

[C.sco]

I think the quote you posted pretty well sums it up; 87 will work "satisfactory" and it won't cause any issues, but 91 will perform more "optimal", by which they probably mean a modest improvement in fuel economy and probably a little more power. Probably the ECU detects lower octane fuel and re-tunes itself accordingly, probably involving (among other things) a decrease in turbo boost.

Usually with turbocharged cars, the higher the octane the better, since it reduces knocking and allows the turbo to run at a higher pressure safely. Most turbocharged cars actually will have problems running anything less than 91 octane, you'll feel the engine really struggling and knocking like crazy. So it's nice that the 4xe can safely run 87.... but with that said, I personally will always run 91 octane in mine. For a modest 20-40 cents per gallon extra (when I'm already paying $5 as it is), it's worth it to me.

 

[pghgregg]

Plan to run premium in hot summer months (or when towing heavy). This engine perform optimally in cool weather with any high quality gas.

 

[Mllcb42]

Probably the ECU detects lower octane fuel and re-tunes itself accordingly

It's more of a case of if it detects knock, it will make some adjustments. Knock is more likely to set in during high load/high temps, so while you may see a difference during high throttle runs or towing, etc, during day to day driving, it isnt likely to make much of any difference.

 

[Sheepish Lord]

Agree with 87, it’s a 2.0L so this thing isn’t making any more power regardless of octane

 

[Tyler-98-W68]

Agree with 87, it’s a 2.0L so this thing isn’t making any more power regardless of octane

It won't make its rated power under certain circumstances without premium fuel

 

[Sheepish Lord]

It won't make its rated power under certain circumstances without premium fuel

This is not true at all. Straight from the hybrid/4Xe supplement manual.

“2.0L HYBRID ENGINE
This engine is designed to meet all emission requirements, and provide satisfactory fuel economy and performance, when using high-quality unleaded regular gasoline having an octane rating of 87, as specified by the (R+M)/2 method.”

All the talk about 91 for towing or hot weather is from the non-4Xe manual and references the 2.0L (non hybrid ver) used in India.

 

[pghgregg]

There is a absolutely a difference between "satisfactory" and "optimal" performance. Most modern engine's ECU tunes will pull timing with lower octane fuel under stress (heat and/or load). They are designed to do this safety and seamlessly so it is up to the individual driver to determine if they want "satisfactory" or "optimal" performance under given conditions.

 

[Tyler-98-W68]

This is not true at all. Straight from the hybrid/4Xe supplement manual.

“2.0L HYBRID ENGINE
This engine is designed to meet all emission requirements, and provide satisfactory fuel economy and performance, when using high-quality unleaded regular gasoline having an octane rating of 87, as specified by the (R+M)/2 method.”

All the talk about 91 for towing or hot weather is from the non-4Xe manual and references the 2.0L (non hybrid ver) used in India.

The 2.0 used in the 4xe is IDENTICAL to the non 4xe wranglers.

Tell me, have you logged engine timing and cross referenced PCM timing tables to ensure that your vehicle is not knocking or pulling when running a certain type of fuel? I sure have and I can tell you that during drag racing my 4xe both running slightly higher than 91 octane do not pull timing or knock.

I look forward to hearing your data driven results not just an opinion.

 

[Sheepish Lord]

The 2.0 used in the 4xe is IDENTICAL to the non 4xe wranglers.

Tell me, have you logged engine timing and cross referenced PCM timing tables to ensure that your vehicle is not knocking or pulling when running a certain type of fuel? I sure have and I can tell you that during drag racing my 4xe both running slightly higher than 91 octane do not pull timing or knock.

I look forward to hearing your data driven results not just an opinion.

You're correct, the motors are identical and therefore both take 87 octane in the non-4Xe manual and 4Xe supplement. And I stand corrected, the 4Xe supplement does state you can use 91 octane in hot weather and towing conditions but if you look at the fuel chart it still says 87 octane is the spec.

My opinion...is the owners manual. Are you telling me running 87 octane, per the owners manual, is causing my engine to knock from the factory? Are you claiming that 87 octane PER THE OWNERS MANUAL is creating a non-optimal environment and only 91 octane or above will prevent pulling or knocking? In the US only 19 out of the 50 States even have 91 octane so with Wrangler sales being vastly larger in the US than any other market, including Canada, why would Jeep not use 89 or 93 octane which is widely more available in the US than 91 if there were knocking issues and that was their main market? So while you're "drag racing" a 4Xe I'm reading a manual from a company that invested $30 BILLION into PHEV/EV production. Guess that's my "opinion" though and I'll drop links to some others below.

https://en.wikipedia.org/wiki/List_of_U.S._states_by_standard_octane_ratings

Jeep Wrangler Sales Figures

Automotive Sales Data and Statistics

www.goodcarbadcar.net

Jeep® Brand Reveals Plan to Become the Leading Electrified SUV Brand on the Market | Stellantis

Jeep® brand will introduce four all-electric SUVs in North America and in Europe by 2025 All Stellantis b

www.stellantis.com

 

[Mllcb42]

Are you telling me running 87 octane, per the owners manual, is causing my engine to knock from the factory?

During high load, high temp conditions, absolutely. That's why in that corner case, you'll get the optimal performance out of higher octane fuel.

That's why the manual provided by the company that invested $30B into phevs tells you that for that corner case, if you want optimal performance, to use 91.

If you don't, its not just going to sit there knocking away but it will adjust timing when it first detects knock... like every other modern engine.

So then, the follow up question to ask yourself is "how often do I find myself in that corner case?" If you're towing a boat up to the mountains in August, by all means, put 91 in. If you're Tyler going to the drag strip and doing full throttle passes, by all means, put the 91 in. If you're just doing your daily commute... not going to make a difference other than to your wallet.

 

[Sprinter69]

There is certainly no downside to running 91+ Premium other than the cost. How will you know whether or not you'll be under high load conditions in the next 400 ICE miles when you fill up a tank of fuel? You can't exactly drain the fuel and replace it if you predicted incorrectly.

 

[Mllcb42]

How will you know whether or not you'll be under high load conditions in the next 400 ICE miles when you fill up a tank of fuel?

Fortunately, the impact to having 87 in there is very low. It's not like hitting a high load condition is going to cause issues, it might just be a little less efficient.

You're taking risk mitigating steps for a risk that has no teeth.

 

[Sprinter69]

Fortunately, the impact to having 87 in there is very low. It's not like hitting a high load condition is going to cause issues, it might just be a little less efficient.

You're taking risk mitigating steps for a risk that has no teeth.

Perhaps the manual could have stated: "The engine will run optimally in all conditions with 91 octane fuel, and in low load conditions will run on 87 minimum octane with no negative effects." Then all of a sudden everyone would be aruging that the manual SAYS you should run 91 and if you're a cheapskate who wants to save a few bucks you can get by with 87. It's exactly the same thing just stated differently.

 

[hddman]

Anyone using 100% gas? It is widely available in my area, costs about .40 cents more per gallon but does seem to return better fuel economy. I try to keep the ethanol out of mine as much as possible.

 

[Sprinter69]

Anyone using 100% gas? It is widely available in my area, costs about .40 cents more per gallon but does seem to return better fuel economy. I try to keep the ethanol out of mine as much as possible.

It's pretty standard to assume 1mpg lower fuel economy in most vehicles with E10. I've seen more than that in some vehicles, more like 2mpg. Unfortunately in some areas you can't get anything but E10. In my round-trips to CO there are areas where I can't get anything but E10 and when towing in my Wrangler it would get 2mpg lower on the E10 every time.

 

[C.sco]

It's pretty standard to assume 1mpg lower fuel economy in most vehicles with E10. I've seen more than that in some vehicles, more like 2mpg. Unfortunately in some areas you can't get anything but E10. In my round-trips to CO there are areas where I can't get anything but E10 and when towing in my Wrangler it would get 2mpg lower on the E10 every time.

It's a bit ironic that they put 10% ethanol in gasoline to burn less petroleum gasoline, but it just causes everyone to have to use 10% more gas, so overall the same amount of petroleum gasoline is getting burned, with or without ethanol mixed in. I mean, just going off the numbers you posted that's kind of what it sounds like to me.

 

[brnscofrnld]

It's a bit ironic that they put 10% ethanol in gasoline to burn less petroleum gasoline, but it just causes everyone to have to use 10% more gas, so overall the same amount of petroleum gasoline is getting burned, with or without ethanol mixed in. I mean, just going off the numbers you posted that's kind of what it sounds like to me.

Ding Ding Ding...

I still need to find the information, but that's pretty much exactly what happens. Ethanol has less energy per gallon than regular straight petroleum based fuel.

Basically, you're watering down the energy in gasoline when you try and go green with ethanol.

Edit...

 

[hddman]

Another reason I use 100% gas is that it doesn't breakdown as fast over time as E10. Months can sometimes pass by before I need to add any fuel to my 4xe.

 

[Sprinter69]

Another reason I use 100% gas is that it doesn't breakdown as fast over time as E10. Months can sometimes pass by before I need to add any fuel to my 4xe.

If you're unfortunate enough to be in an area where E10 is mandated, you can use a fuel stabilizer treatment to somewhat mitigate that.