What octane and type of fuel does your 4.0 like?

[AndyG]

Yes I think that's kind of what I was getting at mine really seems to purr when you put ethanol free fuel in it.

 

[jtf440]

I've always put the cheapest gas in town in the Jeep, but sadly, here in Cali it ain't so cheap

 

[Jerry Bransford]

Ethanol, alcohol, winter blend, etc. aside, the octane level requirement in our TJ engines is 87, nothing higher is required or of any benefit whatsoever. Running 89, 91, etc. will not help anything. Not power, not mpg, not cleanliness.

The only benefit of unnecessarily running more than an 87 octane is more profit to those making and selling the gasoline. Less $$$ in your pocket, more $$$ in their pocket.

I have to run 89 minimum in my BMW and Lexus says to run 91 in my wife's Lexus. So I'll run a higher octane when required or warranted but in the 5 Jeeps I've owned? Never anything but 87.

And no, there's no knock sensor in our TJ engines that would allow them to take advantage of a higher than 87 octane if it was there.

 

[Shatto]

Seems my 4.0 loves non ethanol gas in a slightly higher octane , but it may be in my head .

I realize more octane slows the burn , and ethanol typically doesn't affect larger , fuel injected engines...and they are 2 separate animals.

The Cheapest Top Tier Gas. Costco, Walmart/Sam's, many groceries and of course the major gas stations.. Save more by using your GasBuddy card.

https://en.wikipedia.org/wiki/Top_Tier_Detergent_Gasoline

 

[Shatto]

I only use Shell, Chevron, or Sunoco, lowest octane.

Thank you for proving that Americans still have the right to choose.

My Test:
I-5 from San Francisco to LA. and back. Initial fill up and one more along way. All calculations used gas receipts.
The cars: Fiat 131 station wagon. automatic., Volvo DL, Dodge Dakota V6 automatic, Honda Accord, 62 Chrysler V8 automatic, Tundra V8 automatic, Mazda RX2 rotary 4-speed, Honda Prelude automatic 4WS.
ALL GOT WORSE GAS MILEAGE USING HIGH OCTANE GASOLINE

 

[RaymondT]

I see many ads on TV and in magazines showing actors wearing lab coats and a pair of glass touting their special blend of fuels. What a load of BS! In our province of B.C., fuel is shipped by bulk carriers from a central storage facility such as those in Burnaby and Kamloops. There's about a half-dozen bulk carrier companies that deliver to local stations all over the province. Octane is set by the refinery but the "special" additives that makes it Shell, Chevron, etc, is added at the time of delivery. It's such a minute dilution that it renders any comparisons of brands moot. Good thing there's sheep or all this expensive marketing would be wasted.

 

[Chris]

Good thing there's sheep or all this expensive marketing would be wasted.

Amen!

 

[Boinked]

Good thing there's sheep or all this expensive marketing would be wasted.

What would we do without:
cold air intake
Throttle body spacers
Triple dipped .... special coated... nitrogen frozen spark pulgs.
Super special oil additives
I know i am missing a few hundred. But we are a world of sheep. As long as the smart people are using the power of persuasion for evil purposes. We will continue to buy what they want us to.

 

[Chris]

What would we do without:
cold air intake
Throttle body spacers
Triple dipped .... special coated... nitrogen frozen spark pulgs.
Super special oil additives
I know i am missing a few hundred. But we are a world of sheep. As long as the smart people are using the power of persuasion for evil purposes. We will continue to buy what they want us to.

Wait... you mean those electric superchargers don't really work? :risas3:

 

[toximus]

What would we do without:
cold air intake
Throttle body spacers
Triple dipped .... special coated... nitrogen frozen spark pulgs.
Super special oil additives
I know i am missing a few hundred. But we are a world of sheep. As long as the smart people are using the power of persuasion for evil purposes. We will continue to buy what they want us to.

I mean... there is some truth and fact behind most of those... just depends on application... For example all modern oils include super special oil additives that are awesome.

 

[Boinked]

I mean... there is some truth and fact behind most of those... just depends on application... For example all modern oils include super special oil additives that are awesome.

What i find funny about that. Is everyone alwas says the oil is improving the the life of the engine.
When in reality. (Taken from a phd in material failure —-not me im not that smart) the internal combustion engine materials have improved far more then lubricating. He has said the process are improving so much they are making harder rings and cylinders that resist the normal wear. This is why in the past 30 years we have seen an increase in the life span of the engine. 200k on an engine is nothing. And most normal (non mechanical people) buy the cheap oil. And even places like the corner lube store will toss in cheap oil even when you buy the premium oil. (Many many news reports proving that). Then you have the people who hardly ever change the oil. That engine still will make 200k.
While we make a huge thing about what oils to use and this is better than that. There are people who use the cheap stuff and get the same life ouf of the engine.

I am one of the sheep. I still buy good engine oil and religiously change it. I follow the guidelines in the service manual.

This post is not a bashing on anyone or anything. Just an observation.

 

[Stockli]

There is truth to that one, I agree.

I'm fortunate to live within a mile of several ethanol free gas stations. Of course it might not be worth it anyways, since it's $1 more per gallon, so I'd have to do the math.

Everything runs better without ethanol in it :risas3:

It’s chemistry you can feel. Gasoline has far more carbon carbon and carbon hydrogen bonds than ethanol (only two carbon bonds and 6 hydrogen bonds). Octane is a stable fuel and is really what pure gasoline is. It’s a slow burn with 8 carbons. More carbon bonds is bigger bang, more energy released during combustion reaction as the carbon bonds are broken. Much less energy in ethanol and gases containing ethanol (not that most will notice any significant difference until the ethanol content gets really high, e85). He more pure the pump gas the higher the octane. Lower octane gas contains hydrocarbons other than octane that are not as stable. More carbons to oxidize equals more energy released.

 

[Kiwi TJ]

The lowest octane we have out here is 91 and my Jeep runs really well on that ….. the issue is the price per litre $2.38 NZD (1.60USD) and a litre is only a quarter of a US gallon !!!!!
Soooo very roughly... I'm paying just over $6 US bucks per US gallon!!!!
And you wonder why I cant afford new mods haha

 

[Boinked]

The lowest octane we have out here is 91 and my Jeep runs really well on that ….. the issue is the price per litre $2.38 NZD (1.60USD) and a litre is only a quarter of a US gallon !!!!!
Soooo very roughly... I'm paying just over $6 US bucks per US gallon!!!!
And you wonder why I cant afford new mods haha

But you have the lords of the rings land to drive your jeep in.

 

[mots]

It’s chemistry you can feel. Gasoline has far more carbon carbon and carbon hydrogen bonds than ethanol (only two carbon bonds and 6 hydrogen bonds). Octane is a stable fuel and is really what pure gasoline is. It’s a slow burn with 8 carbons. More carbon bonds is bigger bang, more energy released during combustion reaction as the carbon bonds are broken. Much less energy in ethanol and gases containing ethanol (not that most will notice any significant difference until the ethanol content gets really high, e85). He more pure the pump gas the higher the octane. Lower octane gas contains hydrocarbons other than octane that are not as stable. More carbons to oxidize equals more energy released.

True, unless you are running a boosted engine that can take advantage of Ethanol’s cooling properties. Ethanol reduces knock in boosted engines and allows you to run higher boost wtih more ignition timing....If the fuel system can tolerate it and ECU can take advantage of it. Today’s sophisticated direct injection engines have knock sensors on each cyclinder and the ECU will pull timing when it senses knock in the cylinder, thus reducing power. Ethanol’s cooling properties move the “wall” to a higher compression zone that typical premium gasoline (US 93 octane etc.) has when the compression (heat) reaches a certain point. Ethanol is way cheaper and is often more readily available than race gas. More boost, more oxygen, more power...ethanol keeps things cooler to allow it.

The longer hydrocarbons do have more energy (higher octane number has more longer chains), but there is a disminishing effect when an engine when can’t take advantage of it. At some point, raising the octane has deterimental effects in non-boosted engines because it burns slower and you will start to see unspent fuel and carbon buildup on your valves and piston crowns etc. This is why I run 87 in my Jeep and never anything else. It just isn’t required in a lower compression engine like the 4.0.

With the right tune, ethanol can make a cheap race gas and runs cooler allowing for huge boost numbers. A lot of the UTV racing guys are doing this on short course.

Yep! I run E25-E30 in my tuned VW Golf (safe without a specific ethanol tune). We call it the nectar from the gods, LOL. Regardless of the smaller carbon chains, we can make a lot more power when mixed with regular premium gasoline.

 

[Kiwi TJ]

But you have the lords of the rings land to drive your jeep in.

Very true...shame most of them are in the south island (700miles and a boat ride away)
Although I'll be heading south towards one of those areas once get a weekend off work (4.5 Hour drive)​

 

[Drizit]

The lowest octane we have out here is 91 and my Jeep runs really well on that ….. the issue is the price per litre $2.38 NZD (1.60USD) and a litre is only a quarter of a US gallon !!!!!
Soooo very roughly... I'm paying just over $6 US bucks per US gallon!!!!
And you wonder why I cant afford new mods haha

Thats both better and worse than here then. Vancouver BC is apparently around 1.50 Canadian and Ontario is starting to push close to 1.40. However those prices are for 87, if you want 91 I was looking at the shell (while buying 87) it was $0.21 more expensive per litre.

—
There must have been a time
when we could have said no.

 

[Kiwi TJ]

Thats both better and worse than here then. Vancouver BC is apparently around 1.50 Canadian and Ontario is starting to push close to 1.40. However those prices are for 87, if you want 91 I was looking at the shell (while buying 87) it was $0.21 more expensive per litre.

—
There must have been a time
when we could have said no.

We have 95-96 octane add 30cents or if you feel like splashing out 98 octane 45 cents extra....you have to re-mortgage your house to fill up you car. lol...Lucky Bruiser is happy on 91

 

[Drizit]

We have 95-96 octane add 30cents or if you feel like splashing out 98 octane 45 cents extra....you have to re-mortgage your house to fill up you car. lol...Lucky Bruiser is happy on 91

Ouch, highest we can get at the pump is 93 (pioneer) or 94 (petro Canada) but most max out at 91.

—
There must have been a time
when we could have said no.

 

[AndyG]

I agree the engine internals are far better....and fuel injection is when we really started seeing real longevity- carbs dumping tons of gas dilutes oil and washed cylinder walls possibly (?) .....that's what my dad thinks.