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-   -   Octane Rating 87, 90, Or 92 ? ? ? (http://www.wranglerforum.com/f282/octane-rating-87-90-or-92-a-3576.html)

NOLUCK13 10-22-2006 08:20 PM

Octane Rating 87, 90, Or 92 ? ? ?
 
I been driving Jeeps for awhile now, on my third one. First was a "81 CJ 7, then a "88 YJ, now I own a 4.0 "99 TJ. I wanted to know what octane of gas you all are using ? My owners manual says a rating of atleast 87, duh, but it also says " THE USE OF PREMIUM GASOLINE IS NOT RECOMMENDED. THE USE OF PREMIUM GASOLINE WILL PROVIDE NO BENIFIT OVER HIGH QUALITY REGULAR GASOLINES AND IN SOME CIRCUMSTANCES MAY RESULT IN POORER PERFORMANCE. Where I live in SouthEastern Illinois and where I work in SouthWestern Indiana, the " cheap " 87 grade of gas just smells funny each time I fuel up, and no I don't go around huffing gas, LOL. :D I like to run 90 octane. I just wanted to know what others use and there thoughts...

mrbigjeep 10-22-2006 08:43 PM

87...i don't see any benefit of running a higher octane gas

coolman8bc 10-22-2006 08:46 PM

I agree anything higher is just a waste of money

Jerry Bransford 10-22-2006 09:11 PM

Higher than recommended octane can actually leave more deposits as it burns slower than a lower octane does. In other words, it may not fully combust in an engine not designed for it. Higher octane fuel does NOT add power, the added octane's ONLY purpose is to help the gasoline prevent being ignited prematurely from compression. That is ALL that octane does. So if your engine isn't compressing the fuel enough that it is self-igniting (pinging) on its own, then paying more for high octane is a foolish thing to do. That the gasoline producers love you for doing though. ;)

whiteyj 10-22-2006 11:15 PM

Running 87 in my 4.0 with no problems. Heck I even run that in the 5.3L V-8 in my Tahoe.

Strykar 10-23-2006 03:34 AM

im cheap,,, 87 all the way baby

Mudweiser 10-23-2006 10:47 AM

Guess i had to be the different one. Depends on how tight money is that week on what i put in it. I have done a tank to tank comparison though and i get more miles out of the 93 octane then i do the 87. I run 87 alot but sometimes i will run super just to clean everything out. Keeps everything working smoothly. Some will disagree im sure but i can pull my intake off after burning through a tank of it and hardly any carbon build up at all in it. Do what works fer ya.

mud707 10-23-2006 11:37 AM

higher octane levels of gas are made for use in older vehicles or modified race engines. Octane does not improve mpg at all it helps eliminate knocks that older vehicles have and make them run smoother. So if you don't mind spending extra $$$ for no benefit buy the high price stuff. If not stick to what your owner's manual says.

03Leo 10-23-2006 11:59 AM

Hi
Now i'm a bit confused. I've always used 93 because when I switched to 87 it started rattling/pinging really bad. I'd love to go back to 87 though.

4Jeepn 10-23-2006 12:18 PM

Yes there is a difference between 87 and 93 or what ever the higher number is at your station. The 93 contains cleaners in most cases that the 87 does not. Thus, if you start useing the 93 it may help to clean up a dirty system and you might see some slight gains in mpg, but it most likey means the system is now running how it should be. I know in my truck after about 5-8 fill ups of 87 it has hard start issues. I can do one of two things Dump a 5 dollar bottel of techron in or just use 93 vs 87 every couple of tank fulls.

03Leo 10-23-2006 01:12 PM

Thanks!!!
I guess I'll try 87 when i get my next brand new Wrangler.

Jerry Bransford 10-23-2006 07:02 PM

Quote:

Originally Posted by Mudweiser
I have done a tank to tank comparison though and i get more miles out of the 93 octane then i do the 87.

Those who fully understand what octane is and does know that running higher octane than the engine requires to prevent pinging or knock will not help improve fuel economy even .00001 mpg. Octane has NOTHING to do with fuel economy. Nada, zip. I can do a lot of things that will vary my Jeep's fuel economy but it mainly has to do with my foot. ;)

By the way, even Chevron at http://www.chevron.com/products/prod.../fuel_economy/ says "Don't Buy a Higher-octane Gasoline to Improve Fuel Economy". Now it has been proven that the QUALITY of a gasoline can affect/improve/decrease fuel economy but octane level itself has nothing to do with fuel economy.

1BLKJP 10-23-2006 07:30 PM

Jerry, I think that what some of them are saying is that if you are running a vehicle that the fuel system has been somewhat neglected and you run a higher octange fuel for a couple of tanks, it can in fact increase the effeciency of said vehicle by providing the cleaning agents that haven't been there.

ezjeeper 10-24-2006 02:41 PM

I guess I am unique. They do not have Octane 87 here. I run 86.5 usually. That's the "regular" gasoline level in Europe. My Jeep does ping sometimes, then I throw some higher octane in it to clean it up. Mid-grade is 90 and high is 93.

Jerry Bransford 10-26-2006 12:55 AM

Quote:

Originally Posted by 1BLKJP
Jerry, I think that what some of them are saying is that if you are running a vehicle that the fuel system has been somewhat neglected and you run a higher octange fuel for a couple of tanks, it can in fact increase the effeciency of said vehicle by providing the cleaning agents that haven't been there.

But where they'd be wrong is on the false rumor that higher octane gasolines of today's major brand gasolines have more cleaning additives than, say, 87 octane does. 87 has the same amount of fuel injection cleaning additives as 91 octane does, at least as far as the major brands go. :)

pismo61 10-27-2006 08:22 PM

I also heard Chevron put more techron in the 92-3 octane.As stated the higher octane will do nothing for power in our Jeeps.

chiro2736 04-24-2008 08:02 PM

I was running 87 when I bought the Jeep, It pinged like CRAZY!
Since then I fill up with 91 and the i6 no loger pings! But every vehicle is different!

-John

richp 04-24-2008 08:25 PM

Quote:

Originally Posted by chiro2736 (Post 222237)
I was running 87 when I bought the Jeep, It pinged like CRAZY!
Since then I fill up with 91 and the i6 no loger pings! But every vehicle is different!

-John

If it is pinging with 87 it's because you have carbon build up in the cylinder head, this carbon gets hot and glows which in turn causes the gas to ignite early, when you run higher octane it has inhibitors that make it harder for that carbon or the spark plugs to ignite the mix. What you need to do is get the carbon out of the combustion chamber. There are several ways to do this, Chevron Techron FUEL SYSTEM CLEANER [Not fuel injection cleaner], Sea Foam poured thru the throttle body and left to soak or if you have the knack you can use water dribbled into the running throttle body. The water does a really good job, the engine turns it to steam which penetrates the carbon and expands within the carbon blowing the carbon out big time. What you have to be careful of is too much water which can warp the head pretty dam quick. That I know from personal experience on my moms 66 6 cylinder Mustang way back in 68, I warped the head, I sneezed while pouring :banghead:

[TheYJGuy] 04-25-2008 01:35 AM

Quote:

Originally Posted by mud707 (Post 27772)
higher octane levels of gas are made for use in older vehicles or modified race engines. Octane does not improve mpg at all it helps eliminate knocks that older vehicles have and make them run smoother. So if you don't mind spending extra $$$ for no benefit buy the high price stuff. If not stick to what your owner's manual says.

Higher octane DOES improve fuel economy. The higher the octane, the slower AND cleaner the burn. The slower the burn=less fuel consumption. The cleaner the burn=better and longer engine performance.

I only run 93 octane in ANY Jeep I'll ever own. I find that the higher octane keeps the carbs running a bit better as well.

Jerry Bransford 04-25-2008 10:49 AM

Quote:

Originally Posted by The_YJGuy88 (Post 222374)
Higher octane DOES improve fuel economy. The higher the octane, the slower AND cleaner the burn.

I hate to be so blunt and I seldom am this blunt but that is complete baloney. More octane than the engine is designed for does not improve fuel economy, and higher octane fuel certainly does not burn cleaner or leave fewer deposits behind in an engine designed to run with a lower octane. :)

MOz 04-25-2008 11:55 AM

Quote:

Originally Posted by richp (Post 222245)
If it is pinging with 87 it's because you have carbon build up in the cylinder head, this carbon gets hot and glows which in turn causes the gas to ignite early, when you run higher octane it has inhibitors that make it harder for that carbon or the spark plugs to ignite the mix. What you need to do is get the carbon out of the combustion chamber. There are several ways to do this, Chevron Techron FUEL SYSTEM CLEANER [Not fuel injection cleaner], Sea Foam poured thru the throttle body and left to soak or if you have the knack you can use water dribbled into the running throttle body. The water does a really good job, the engine turns it to steam which penetrates the carbon and expands within the carbon blowing the carbon out big time. What you have to be careful of is too much water which can warp the head pretty dam quick. That I know from personal experience on my moms 66 6 cylinder Mustang way back in 68, I warped the head, I sneezed while pouring :banghead:

x2 - Pinging on 87 mean either bad gas or carbon build up. A can of injection cleaner and a different gas station cured my problems.

MOz 04-25-2008 12:11 PM

Quote:

Originally Posted by The_YJGuy88 (Post 222374)
Higher octane DOES improve fuel economy. The higher the octane, the slower AND cleaner the burn. The slower the burn=less fuel consumption. The cleaner the burn=better and longer engine performance.

I only run 93 octane in ANY Jeep I'll ever own. I find that the higher octane keeps the carbs running a bit better as well.

I don't normally take sides...

However, Jerry's right YJ. I had a fluid dynamics professor at Morris County College explain this to me. Higher octane gas burns more efficiently....(leaving less un-burned fuel). Higher octane is required in engines that require higher performance...such as higher compression ratios and motors that have 3-4 valves per cyclinder. There are no hp gains in running a higher octane fuel.

Ever try running 87 octane in a V-8 motor with 12:1 compression???? It will ping all day long and you will damage the pistons and valves because of the unburned residues ....You need Hess 101 or Cam2....

The 4.0L is not a high compression motor and does not need 93. However, I will say, if your engine is pinging, running 93 (for a short term) will fix the immediate issue. However, this may not solve the problem in the long run. The gas station may be giving you gas that has a marginal or lower 87 rating. I had this exact issue with the local Exxon station by me...so now I go to Lukoil and have not had any issues running their 87.

sailsurf7713 04-25-2008 02:08 PM

I run 89 and star-tron which has a very mild octane booster, reduces separation of ethanol and gasoline and also has fuel system and combustion chamber cleaning properties. I run 89 due to the fact that my old 3.9 Magnum, even after sea foam, consistently got 20 miles more per tank than it did on 87 and had a lower compression ratio than the 2.5. I'd say for the 2.5 and 4.0, 87-89 is quite optimal and anything higher is a big waste of money. I once got 93 for the price of 87 at a gas station cause they ran out of 87 and 89 and my 3.9 Magnum ran like complete shit.

Just my 2 cents.

[TheYJGuy] 04-25-2008 04:48 PM

Quote:

Originally Posted by MOz (Post 222449)
I don't normally take sides...

Then I guess it depends on the driver, but anytime I ran 87, my 4.2 would spit, sputter and die. I'd have to use octane boost to get anything out of 87 octane.

And on an unrelated note, I have several friends attending CCM :D

wheelin352 04-25-2008 05:48 PM

Quote:

Originally Posted by NOLUCK13 (Post 27737)
the " cheap " 87 grade of gas just smells funny each time I fuel up, and no I don't go around huffing gas

what iv been told that funny smell is ethanol they are now adding to the gas i found that i get better mpg with the places that are adding 10% ethanol. i used to get maybe 180 miles per tank and since they started adding ethanol im get atleast 200 with no change to the jeep

Jerry Bransford 04-25-2008 05:55 PM

The EPA says Ethanol will slightly reduce fuel economy, not improve it. :)

richp 04-25-2008 07:27 PM

Thats the strange part, back in 2001 I was working a contract in Fairfield NJ, about that time they dropped that MTB stuff and started using ethanol as the winter additive [for you warm climate types, cold states change to 'winter fuel' around Oct 1 till April 1]. I was commuting 61 miles each way, keeping very good track of my mileage for tax purposes so I kept a log. When the winter fuel hit I expected a 1-2mpg drop, got the exact opposite in the 4.0L 5 speed XJ. What I think happened is the ethanol cleaned the engine out, I was only adding Chevron Techron about every 4-5K miles but getting a full tank of winter gas every two days or so at the Sunoco in Fairfield. I actually got better mileage with the winter stuff. Now the other interesting part was when I filled up with Sunoco in Pa near home my mileage went back down, up in the pokes they did not switch to winter mix, that was only required in the big cities for cars that would spend excessive time idling in traffic so the boonies were exempt. No explanation only speculation, I have noticed that we tend to get more crap gas up here than down towards Allentown which has always convinced me that the suppliers may be slipping other stuff in there to make it go further, either way I don't trust them. Thats also one of the reasons I drag empty 5 gallon containers with me when I head to NJ, not only is it 25 cents cheaper per gallon I think it's better gas, NJ tends to be somewhat aggressive with their inspections and testing.

Triple88a 04-25-2008 07:28 PM

Quote:

Originally Posted by wheelin352 (Post 222536)
I used to get maybe 180 miles per tank and since they started adding ethanol im get atleast 200 with no change to the jeep

Summer vs winter? Longer more continuous trips? Smooth accelerating?

Quote:

Originally Posted by Jerry Bransford (Post 222541)
The EPA says Ethanol will slightly reduce fuel economy, not improve it. :)

2x,

Ethanol has ~60% of the energy standard gasoline has.

richp 04-25-2008 07:32 PM

Quote:

Originally Posted by Triple88a (Post 222589)
Summer vs winter? Longer more continuous trips? Smooth accelerating?


2x,

Ethanol has ~60% of the energy standard gasoline has.

That last part is somewhat true, if you up the compression to 11 or 11.5:1 the ethanol will get better MPG than gas will in the lower compression engines. Have some people I know in Brazil that have jeeps with 4.0 export engines that are high compression from the factory, not available here by law. They report about 30MPG on those high compression XJ's they have.

richp 04-25-2008 07:35 PM

Hey jerry, hows the prices down in TJ on gas ? Is there still a line to get across there. Saw on the news the other nite about a trucking company that was running across in texas and filling their trucks with $2 diesel, the feds stopped them on the second trip when they brought back a 500 gallon tank on a trailer. That tells me the mexican govt is subsidizing their nafta truckers with cheap fuel.


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