Sold on 89 Octane

[jadmt]

87 here is $3.42, 89 $3.62 and 91 $3.82

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[Zuni]

Yep! Most people have no clue to 11.5:1 compression. Geeze, less than 15 years ago some regular gas engines had 10:1 if so lucky. Wizardry has really changed what was believed impossible when big blocks ruled the streets.

Detonation or knock/ping can do some bad things besides blow holes in pistons.

Heat does play a big factor, but as far as I can tell Mopar has a rich mixture. Don't know if it is through out the torque band width but it does exist. I noticed almost right away cold start idle seems smoother and all in all quieter. Not valve train noise but through muffler.

I have already done the oil replacement with Valvoline Restore & Protect so things are cleaning up both oil and burning of fuel.

I did get my best previous average MPG through Pedal Monster, and kept it at City with low response and high speed trim since getting good results.

If I were to rely more on higher rpm power, 91 octane would be my choice.

I am surprised how fast the ECU adjusted to the octane change. I don't need to look at the average MPG reading. The fuel gauge has slowed to where 1/8 tank would normally be consumed to almost 1/10 of a tank for the same route and speeds.

Going up steep grades are impossible to fudge MPG. 5MPG to 9MPG for 1/2 mile and more.

One thing about automatic gear selection. It will shift into 5th and 6th just to get into the 3000RPM band. Even though a higher gear would drop down to save fuel. In the long run bumping up to 70MPH and keeping steady does save fuel more than babying through 6th and 7th gear at 60 or 65MPH.

I kind of disagree with your last statement although I have a 6 speed manual transmission not an automatic. I've found at 70MPH in 5th I'm doing about 2350RPM or so but I lose about 1-1.5 MPG over 60 in 5th at 2050RPM. I blame it on aerodynamics.
And why does a wrangler need a HO engine? I consider an engine with a high compression ratio and higher RPM power curve HO. I like the lower RPM power (torque) like the old 4.0s!
I run 87 octane in my 3.6 with no problems.

 

[YBABRAT]

You are already in the power band of 2000RPM
6 spd manual has less gears, depending on driving conditions shifting may be more often than maintaining RPM and speed at a constant level.
I explained that 89 does help, but the gearing and how much you rely on over drive gears that keep you lower than 2000RPM, can effect MPG.

I have a 2 door and the only difference between aerodynamics between other JL trims and my Jeep is height is length.

I have no clue as to why compression is where it is with the v6. Other than for hotter and better burn efficiency.

 

[LittleE82]

Since my first gas fill up, I've always used 91. I just thought that's what I was supposed to do with a higher compression rate? I didn't realize until I thoroughly read up on my car (this is my first Jeep), that 87 was recommended. I'll just stick with 91 since that's what I've been doing since the beginning. Chevron or Shell gas seems to be the best.

 

[RBesse3333]

I did two tanks of Sonoco 89 and by 1/2 of second tank things stabilized to show better all around.

Top Avg MPG before move to 89... 22.4 MPG on 30 mile mountain hwy.
Now with 89, I get 25.6 MPG. I noticed better performance too. I could have had 26 MPG if my exit was not on a steep grade hill.

This recent measurement was in 90°F sunny day drive.

I think 89 is the minimum we should run on today's Mopar engines, even though manual states regular gas.

The knock sensor isn't retarding the timing as much so you get better milage.

 

[YBABRAT]

The knock sensor isn't retarding the timing as much so you get better milage.

Right but there are other factors and variables. Some don't see an advantage in power or fuel economy. That's what I tried to sort out with gearing and rpm range.

 

[Trails]

fyi
the gas station only has two big tanks. There is no tank for 89 octane. It is blended at the pump.

Yes, and we can blend it for less cost by pumping half 87 and half 93 into our gas tank to end up with 90, and pay less than what they charge for 89.

 

[sunset]

Yes, and we can blend it for less cost by pumping half 87 and half 93 into our gas tank to end up with 90, and pay less than what they charge for 89.

That makes me want to ask... does new gas pumped into the tank distribute itself uniformly with whatever amount of gas is already in the tank? I could almost think it would have to, but, then again, everybody also says that adding alcohol to cooking will "burn off" and on that idea I researched and found that everybody is wrong.

 

[YBABRAT]

As long as you have 50% or less in tank, the fill will mix by turbulance and displacement.. Once on road fuel will mix further by rocking effect.

 

[azjl#3]

And why does a wrangler need a HO engine?

Not that it needs it, but it's cheap because they put them in everything.

 

[mudpup]

I’ve never had an issue with 87 in all the 3.6s I’ve owned
No knock, no ping.
Full tank today with the grocery savings card.
Use a top shelf gas station and save coin.
Far greater things to worry about.

 

[4Play1]

I did two tanks of Sonoco 89 and by 1/2 of second tank things stabilized to show better all around.

Top Avg MPG before move to 89... 22.4 MPG on 30 mile mountain hwy.
Now with 89, I get 25.6 MPG. I noticed better performance too. I could have had 26 MPG if my exit was not on a steep grade hill.

This recent measurement was in 90°F sunny day drive.

I think 89 is the minimum we should run on today's Mopar engines, even though manual states regular gas.

89 is all I have used since day one. Average 24 mpg.

 

[Zuni]

Not that it needs it, but it's cheap because they put them in everything.

Plus better fuel mileage.

 

[Zuni]

That makes me want to ask... does new gas pumped into the tank distribute itself uniformly with whatever amount of gas is already in the tank? I could almost think it would have to, but, then again, everybody also says that adding alcohol to cooking will "burn off" and on that idea I researched and found that everybody is wrong.

Umm...not sure where u got that but alcohol boils at a lot less temperature than even water let alone oil. If any boiling is involved all that would be left is flavor. Simmering might take a minute or 2.
Wave dynamics says yes it will mix together at least mostly I would think.

 

[sunset]

Umm...not sure where u got that but alcohol boils at a lot less temperature than even water let alone oil. If any boiling is involved all that would be left is flavor. Simmering might take a minute or 2.
Wave dynamics says yes it will mix together at least mostly I would think.

This is admittedly off-topic, but for something to "burn off" it would literally have to be burning, as in being on fire. Dump some beer into a pot of chili and there will be no flame established. So this chosen nomenclature is the first thing wrong with people's acceptance of this.

Secondly, people seem to accept that it "burns off" without critical response. If I dumped a shot glass full of urine into your pot of chili and told you with confidence to not worry because it "burns off", would you be so accepting? Nope. Besides reacting to the unsavoriness of this, all of your intellectual suspicion would surface quickly, as it should, unlike when people tell us the alcohol "burns off" where we all seem to mindlessly accept it as truth.

You mention boiling point. Does alcohol "boil off"? Do you boil your chili, or only heat it up? For how long to you actually boil your chili at the boiling point? Long enough to know for a fact that the alcohol you added was removed? Are you sure it's at the actual boiling temperature and throughout the entire pot of chili? Do chefs in restaurants boil all the food to which they add alcohol, and boil it long enough to evaporate all of it at the expense of the integrity of the dish they are creating? Nope. This boiling point idea is not occurring in practice, is it?

One can intellectually posit what you have said but the error is in us thinking the situations in the real world cooperate with the arguments we make.

So, I had my suspicions about "burns off" and did my own research. Seems others went before me.

I have attached a PDF I made of a collection of articles on the topic. You might be surprised how much of the added alcohol remains in the food to which it is added. Burning off is decidedly a myth.

Thanks.

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