Premium 92

 

In Colorado, we have **** grade (85 octane), regular (87 octane), and mid grade (91 octane)

With gas prices being as cheap as they were this winter, I only put in 91 octane.

In the summer, I will run regular (87 octane) because my XJ will start to run rough when it gets really hot with 85, because gas prices go up and I can't afford to throw that much money away...

Plus the 4.0 barely makes enough power to get up I-70 in the Rockies that I need all the help I can get

 

putting premium gas in a Cherokee:

 

 

I tow a camper and I run 91 octane as recommended by the Jeep towing guide.

 

Use midgrade high-test: I always used regular in all my Jeeps-- but then for the hell of it, tanked up with midgrade last summer and immediately noticed the positive difference. Yeah I know technically it should not help and is throwing some loose money out the window. But honestly I think it runs more smoothly and performs better. Have not noticed a change in mileage except for a hunch that it is slightly better too. That last bit could be just wishful thinking. Anyway for what it's worth I have 175,000 mi on my Cherokee XJ. It sits for months at a time because I am working overseas and then when home I put heavy duty high miles on it -- summing up, go for the high-test. Can't hurt. May help.
I also see lots of comments: so let us all know what you think after several tankfuls of trial run.

 

Sometimes I top it off with 85, otherwise I try to run 87. Not sure why CO has 85, I thought it had to do with the altitude / atmospheric pressure vs compression in the engine, which is why 93 isn't offered but no clue.

 

91.


Because stroker.

 

87 and the jeep never complains. Once in a while I throw in some 91 no ethanol just because I'm filling up a sled or a wheeler on the trailer and it's already flowing. Can't say I feel a difference with the pricy stuff.

 

http://www.denverpost.com/latin/ci_4503169

Never had a problem with the 85, though 90% of my trips are to higher elevations in the mountains. Never driven the jeep downhill to Kansas.

 

All justified reasons to spend more money at the pump. BTW BruceB, not so much in newer vehicles, but it's been more of an older practice to increase the octane when you're towing... keeps it from knockin' and pinging due to the increased load on the motor. Ergo, the book's recommendation.

Honestly though, people, unless you're towing, upped the compression, or upgraded your spark (or other performance upgrades that change the F/A ratio), there's no need to run high octane. This has been beat to death in this thread.

BUT... it's yo money!

 

I'm an opinionated old a-hole. I am also a "geardo" when it comes to guns, body armor, knives, or "gear" of any type I try to get the best, so throwing 92 in a 22 year old jeep is more than likely a compensatory measure on my part. LOL

 

lol... I find no shame in that.

 

Regular,regular & regular.

 

My Jeep spent its whole life in central PA prior to me adopting it and bringing it to the big city. Pretty sure it drank non-ethanol since new and now it's getting 10% ethanol (thanks Maryland!) so for giggles I ran the tank down and put in a tank of 93 (because we only have 87, 89 and 93 here) and I could feel a difference. It had more power and started better. So now all of my cars run 93... so much for having a cheap to operate second car! :P