Gas question
Senior Member
Joined: Sep 2014
Posts: 580
Likes: 0
From: Saginaw Mi area
Year: 1994
Model: Cherokee
Engine: 4.0
I put avgas in my lawn tractor & push mower for winter storage, and also my emergency generator. The generator sat for a couple of years ( no power outage for once !) and I had forgot to put good gas in it. And as many of you know, the ethanol did a number on the carb in it. Had to clean & dig all the crap out of it.
We now have two stations that I know of, that have non-ethanol gas, referred to as "recreational" gas.
I can remember when ethanol gas was first used in the east coast marinas, maybe unknown to boat owners (?) and all the damage it did to engines and old fiberglass fuel tanks. Seems like the old type resins used on early tanks would dissolve a bit & get into the fuel mix, ending up in engines etc.
We now have two stations that I know of, that have non-ethanol gas, referred to as "recreational" gas.
I can remember when ethanol gas was first used in the east coast marinas, maybe unknown to boat owners (?) and all the damage it did to engines and old fiberglass fuel tanks. Seems like the old type resins used on early tanks would dissolve a bit & get into the fuel mix, ending up in engines etc.
Senior Member
Joined: Apr 2013
Posts: 781
Likes: 2
From: Dawson Springs, KY
Year: 1985
Model: Cherokee
Engine: 2.5L
Anyone shed any light on the altitude vs lower octane thing? I read it has to do with atmospheric pressure and the compression ratios of engines and that relating to the octanes which are determined at sea level compression rates, they interact differently with the oxygen levels or some crap.
Herp Derp Jerp

Joined: Nov 2011
Posts: 18,251
Likes: 17
From: Parham, ON
Year: 1999
Model: Cherokee
Engine: 4.0L OBD-II
I can remember when ethanol gas was first used in the east coast marinas, maybe unknown to boat owners (?) and all the damage it did to engines and old fiberglass fuel tanks. Seems like the old type resins used on early tanks would dissolve a bit & get into the fuel mix, ending up in engines etc.
Bingo ^^ Higher "octane" resist pre-ignition cause by heat from compression - less pressure, less heat. Don't need to have a high-compression engine or forced induction for that problem, either: Running in very hot climates can require higher rated fuel.
Senior Member

Joined: May 2012
Posts: 925
Likes: 5
From: Fort Erie, CANADA
Year: 1987
Model: Cherokee
Engine: 4.0
You may want to check that. I see you're in Canada, but in the US at least, in order to be considered "Top Tier" gas, it must contain 8% to 10% ethanol. That includes all octane levels. The gasoline at the majority of stations in the US contains 10% ethanol in all gasoline coming out of their pumps.
I have a hunch that's the same in Canada, and the premium fuel you're pumping is still giving you ethanol at greater cost with no advantage. Down here, the pumps usually say something like "All fuels contain up to 10% ethanol by volume."
I have a hunch that's the same in Canada, and the premium fuel you're pumping is still giving you ethanol at greater cost with no advantage. Down here, the pumps usually say something like "All fuels contain up to 10% ethanol by volume."
2. Is Shell V-Power premium gasoline safe for all vehicles?
- Shell V-Power is effective in all gasoline-powered engines found in conventional, modern and hybrid vehicles as well as motorcycles, snowmobiles, and leisure marine vehicles.
- Tested in today’s advanced turbo-charged and direct injection engines, Shell V-Power helps resist thermal breakdown at high temperatures, actively protecting against gunk under tough engine conditions.
- Shell V-Power premium gasoline in Canada does not contain ethanol.
CF Veteran
Joined: Nov 2009
Posts: 8,172
Likes: 17
From: The Republic of TEXAS
Year: 1998
Model: Cherokee
Engine: 4.0L HO
I have to say that I did get a little better mileage by switching to mid grade gasoline, but it was because of the only reason that it will increase mileage. I have the ignition timing set about 4 degrees advanced over stock and with regular I get some pinging, and the pre-ignition that causes pinging will lower your mileage(along with destroying the engine eventually).
With a carbureted 2.5L you need everything you can do to get more power
With a carbureted 2.5L you need everything you can do to get more power

Senior Member
Joined: Sep 2014
Posts: 580
Likes: 0
From: Saginaw Mi area
Year: 1994
Model: Cherokee
Engine: 4.0
A few years ago, one of the oil people in a middle-East country said he just didn't understand why the US is using food ( corn) for fuel. I agree with him, but politics is/are politics....
CF Veteran
Joined: Oct 2009
Posts: 2,867
Likes: 16
From: Fauquier County, Virginia
Year: 1991
Model: Cherokee
Engine: I-6 4.0 HO
Whats funny is that I worked with a few yuppie ***** who drank the 'ethanol saves the world' kool-aid.
Edited, as proper.
Last edited by 1991Jeep_Man; Jan 3, 2015 at 05:53 PM.
Herp Derp Jerp

Joined: Nov 2011
Posts: 18,251
Likes: 17
From: Parham, ON
Year: 1999
Model: Cherokee
Engine: 4.0L OBD-II
Drop the political crap please. Read the forum rules.
Last edited by salad; Jan 3, 2015 at 11:19 AM.
CF Veteran
Joined: Oct 2009
Posts: 2,867
Likes: 16
From: Fauquier County, Virginia
Year: 1991
Model: Cherokee
Engine: I-6 4.0 HO
You mean Dubya? Energy Policy Act of 2005 and Energy Independence and Security Act of 2007 are reponsible for the current state of ethanol in the United States. Or Bush Sr, under whom the Clean Air Act was amended in 1992 to call for reduced carbon monoxide emissions?
Drop the political crap please. Read the forum rules.
My shoe doesnt taste very good...
Seasoned Member
Joined: Nov 2013
Posts: 347
Likes: 0
From: Boston
Year: 1993
Model: Cherokee
Engine: 4.0 Litre
What????? I presume the OP is in the USA, not the land of Oz. If that's the case, then 87 is the lowest octane the OP can find and 87 will be perfect for his XJ. 89, 91, etc. willl not damage/harm the OP's XJ in any way........again, anything higher than 87, in a properly tuned/maintained vehicle designed to run on 87, is just wasting money.
CF Veteran
Joined: Oct 2009
Posts: 2,867
Likes: 16
From: Fauquier County, Virginia
Year: 1991
Model: Cherokee
Engine: I-6 4.0 HO
CF Veteran
Joined: Nov 2009
Posts: 8,172
Likes: 17
From: The Republic of TEXAS
Year: 1998
Model: Cherokee
Engine: 4.0L HO
Banned
Joined: Feb 2014
Posts: 2,379
Likes: 18
From: Florida
Year: 2000
Model: Cherokee(XJ)
Engine: Golen 4.6L
Last month I fueled up a rental car with 85 at a station in Los Alamos, NM. That was at 7300 feet.
Seasoned Member
Joined: Nov 2013
Posts: 347
Likes: 0
From: Boston
Year: 1993
Model: Cherokee
Engine: 4.0 Litre


