does anyone use premium gas in their jk ? does it do anything?

 

Premium does not do a damn thing. The octane number given is a point of ignition in simple terms. Burns at a sooner flash point then lower octane. Should not do a thing for your jeep tuned for a different fuel. Now I say this but my first truck, 1994 chevy 4.3 L, ran better with higher octane. By no means tuned for it.

 

Yeah I wouldn't use higher octane in these things.

 

I wouldn't use BP gas if they paid me..... Well maybe if they paid me!

Let's not forget how BP effed us in the gulf.

 

Higher octane won't do a thing unless there is something wrong causing the knock sensor to tell the PCM to retard the timing. In that case, higher octane will allow the engine to run with less spark retard, resulting in a little better performance.
The root cause will remain uncorrected, though.

 

I noticed 80's and 90's GM vehicles could have any timing set at the factory. I have a 89 Firebird that I put a hypertech chip in and it improved the performance but said I needed to run 91 octane, so I did. Well I was home on leave one weekend and I told my friends dad, who was a GM mastertech, about the chip. He said let's go out and check you base timing, I didn't even know the timing was still adjustable since it was computer controlled. Sure enough, it was retarded, he said it was very common for the timing to be set wrong at the factory. We added 6-7 degrees to the base timing and it added more performance than the chip did. I was very happy. I probably didn't need the 91 octane until we added that timing so I probably wasted a months worth of premium.

 

Octane is the capacity for the fuel to explode under pressure. The higher the octane the more pressure it can resist, that's why its used on high compression/high performance vehicles. Engine knock = fuel exploding before the power stroke or spark.

Two of my vehicles require premium fuel and that's what I use on them. The rest use regular just like the manufacturer and the engineer that designed the motor intended.

Using high octane fuel in a vehicle that requires regular will only make one thing faster... your money dissapear.


This has been discussed many times.

 

I noticed a slight increase in MPGs with 89 which is mid grade here. No significant benefit with 93 octane. I use 89 on my Jeep, I find my Jeep runs better and it actually is almost 2 cents per mile cheaper to run it.

 

It was an ACCIDENT. Drilling miles down is tough work, would you rather not have fuel? You can lay some blame on the government, too, for not allowing drilling in Alaska and other places more accessible.

 

I am using 91 octane with a Superchips 91 tune. My Jeep runs better with the 91 tune over the 87 tune. I also get better mileage with the 91 octane gas. I am willing to pay a few bucks more for 91 for a little better performance, even if it turns out to be only in my head. But I dont think it is only in my head.