Premium Petroleum

Premium gas is a waste of money in an engine that does not require it. Save your money and get a better winch. ;-)

One my 86 CJ7 with the 258 carb engine set up manually I have more than a 100 miles per tank difference between 87 and 91 octane and a serious high speed power difference.

On my 88 Cherokee 4.0 engine, no difference.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

Joshua Nels>

Approximately 9/4/03 14:13, Joshua Nelson uttered for posterity:

If your engine does not have a knock sensor, a higher octane has no effect on horsepower or mileage that cannot be accounted for as well by simple brand to brand or batch to batch variations. Disclaimer that anecdotal reports of superior cleaning abilities of higher octane exist from credible sources. Note that this applies if your engine does not ping on the cheaper octane, with a suggestion that if it does ping slightly on the highway under load, stepping up a grade to inhibit this under heavy climbing is extremely cheap insurance.

If you are driving heavy off road, you need to change oil more often, particularly in the desert, whether synth or dino. However anecdotal reports of better mileage from credible sources exist that a synth or synth blend does help with same.

Or you could retitle the posting "Yet another boring repeat of the same old thread... "

hi joshua, run 87 octane and dyno oil. the money saved goes a long way in jeep mods that will make a _real_ difference that you will appreciate every time you go off road.

Synthetic oil, yes. It holds up better during heavy use. Premium gasoline? Haven't heard of that one. My 90 and my 98 were both designed to run on 87 and do that just fine on and off the road.

Depends on how long you want to keep it.

is it even possible to break down premium (valvoline/castrol) dino in 3000 miles or less?

ive gotten over 400,000 _hard_ miles out of one engine that was dino oil'd every 3000 miles. granted it was a toyota 4 cylinder but still, even a toyota requires lubrication.

? please explain.

Use the lowest octane that doesn't result in engine ping. Anything more is money out the tailpipe.

I'm not a fan of synthetic oil in jeeps, unless its been run with synthetics since the first oil change. Switching to synthetics on a vehicle with a few miles may result in maddening leaks that you didn't have before. Also, its hard to justify the increased cost, especially since offroad use introduces dust and other contaminants that aren't issues on street cars, and which will require you to change oil more often than the extended frequencies touted by the synthetic manufacturers. My advice is to stick with dino oil, and change it every 3,000 miles.

Robert Bills KG6LMV Orange County CA

Approximately 9/4/03 18:00, Nathan W. Collier uttered for posterity:

Seriously doubt it, although a good synth may hold viscosity better at high temperatures and load. Also seems [judging purely from the notoriously inaccurate guage] to hold pressure as well in desert temps. And I *still* change at 3000.

Not sure that's fair, since I've seen a Toyota engine run out of oil [loose filter] to the point it stopped... and then after a good dose of STP and Marvel mixture, run for another dozen years. Don't think I'll try this on my own engine, thanks.

sorta what i was thinking. i know dino is good enough for a couple hundred thousand miles anyway (if changed ever 3k) and personally i dont want to be driving a daily driver with that much mileage anyway. the toyota i mentioned earlier was used commercially, even towed 12,000 pounds occassionally.

never had a problem with the lower octanes. run the cheap stuff - you can spend more on mod's that way. =)

also, if you off road, especially in dusty conditions, change the oil and check the air filter more frequently.

I dont think Toyota is a fair comparison. I have seen the abuse they can take and still keep running - like running until there is almost no oil, and then filling it up and starting it up and driving it again.

sad thing is i have the same expectations of my jeep! :-)

.......now if i can just keep one long enough to put those expectations to the test!

I'm with Mike on this....the higher the octane the more timming you can run. I don't run much advance....Just tune it for mid grade. I can feel and see the difference at hwy speeds. Thats my take on it.....now if your running with new OBDII and engine management systems higher octane aint worth a crap......run what the factory says.

The oil I think is a toss up....I change the oil in my Jeep every 2k with dino. BUT I use Mobile 1 Synthetic in my Z28. Thank god I only drive it a few thousand miles a year cuz its $40 for a driveway oil change.

Brian

88 YJ

A 99 cent bottle of STP fuel treatment every 3,000 miles will take care of that. A lot cheaper than the 30 cent/gal. differential between regular and premium.

Robert Bills KG6LMV Orange County CA