What grade of fuel do you burn in you CJ?

[MDJEEPER]

Regular, mid-grade, premimum, or something special?

Any problems with knocking/pinging when using regular 87 octane??

 

[BajaEdition]

Dauntliss 225, use 87 grade regular, no problems

 

[mylittlecj5]

Cheapest stuff I can get

 

[Sasquach]

Regular....with an 8.0-1 compression ratio it's all you need in a I6.

 

[coldwater]

I-6 cheap gas.

 

[Old Dog]

350 sbc. 87 with 2 cycle oil mixed in.

 

[IOPort51]

Regular gas, if it knocks it is time for a tune or a change in brand. I have found that the quality of gasoline depends more on where you get it than what the octane is. At the moment I do not have good things to say about Exon/Mobil.

 

[dslywalker]

350 sbc. 87 with 2 cycle oil mixed in.

87 grade.Whats the 2 cycle oil do for you Old Dog
Thanx Mike

 

[Old Dog]

We talked about it here http://www.jeep-cj.com/forums/f49/fuel-additives-2058/. I use it in everything I own now.

 

[hole]

91 with I6 and Mopar MPI, anything less and she knocks

 

[gillmore]

All is well with 87 in my AMC 304 with a proper tune.

 

[BrockGrimes]

86 in the I6
88 in the Rubicon

For those who don't know HI-Octane doesn't equal better performance.
It just prevents pre-detonation.

Trying to explain the difference in octane to the local bench racers
has almost given me a stroke. They think 110 race gas will make
their stock 305 chevy motor in the their camaro go faster.

 

[mylittlecj5]

86 in the I6
88 in the Rubicon

For those who don't know HI-Octane doesn't equal better performance.
It just prevents pre-detonation.

Trying to explain the difference in octane to the local bench racers
has almost given me a stroke. They think 110 race gas will make
their stock 305 chevy motor in the their camaro go faster.

SO True...

 

[LongHorn]

I run premium, but I also run 12 degrees initial advance with 10.25 to 1 compression.

 

[66cj5a]

134 inline 4 in a 66cj5a, 87 octane with no probs. 7.something compression so i could very well use anything this side of water.

 

[BajaEdition]

Octane is the ability of a gas not to burn,
So why is that important
Hi compression engines have a habit of preigniting the gas, so if you buy a high performance engine you need to run a gas that burns when you want it to burn and not before.
Like stated, so many guys think it means more power and through good money away using it when they fill up their vehicles that do not need the higher octane.
Now that was simple, here is the real tricky part of the situation, if you read the octane rating on the pump, it is a RON + MON / 2 method of determining octane. Now with 2 standards of coming up with the octane number, RON and MON that makes sense as on method comes up with lower numbers than the other but both test systems are valid, so Oil Companies add the 2 and divide for the number on the pump. However if you look in a owners manual for the octane they suggest for your vehicle. it is rated in the Mon number that consistently comes up with the lower number. So If yo read that your vehicle needs a gas rated at MON 89 and are pruchasing a RON + MON / 2 Gas of 89 you are probably buying a gas that is rated higher than you need to be.

 

[BrockGrimes]

Exactly it's no rocket science, but try explaining that to a jackass.

 

[BajaEdition]

I know, but Brock, you know until the days of the internet and being able to access such info easily, I at one time thought Octane meant power. So I can forgive anyone for not knowing as it is street knowledge or as we call it urban legend. And we all know that if everyone else is wrong with us we must be right because everyone believes it.

 

[Trapshooter]

My AMC 304 does just dandy with regular unleaded......

 

[nitor]

My AMC 304 does just dandy with regular unleaded......

My AMC 258 i6 / 4.2l does just fine on regular unleaded. The stuff is expensive enough without putting extra stuff in.