I just tried a tank of mid grade unleaded fuel (87 oct) vs the normal unleaded (85 oct) and noticed a big improvement in the way my FJ40 runs. Just curious if others have had a similar experiance and what they run.
Unleaded fuel (1 Viewer)
- Thread starter Romer
- Start date
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I usually see 87 oct. listed as regular, 89 as mid-grade, 91 as plus, and 93 as premium or somthing like that. 87 is what i run in my petrol vehicles. Can't usually find 85 oct. but if it was cheaper i'd buy it! 
Mine likes the 87 octane best.
red66toy
Supporting Vendor
Funny, I have never heard of 85 octane. I have always run the regular 87 octane and my cruiser seems happy.
87 is the lowest octane commonly sold in California.
It keeps a cruiser rust free.
Mike S
It keeps a cruiser rust free.
Mike S
I run 87(lowest sold in WA) in all but the 100 series which takes 91(but I have run 89 with no problem)
I just filled the green 82 up with 89(by mistake), so we will see if it makes any difference, so far I can tell none.
I just filled the green 82 up with 89(by mistake), so we will see if it makes any difference, so far I can tell none.
Here we have the range 87, 89, 90 and 91. There is no question after trying them all, that my F engine likes the higher octane better. (Maybe that is why I get 18 mpg, like I did on my little excursion to the river yesterday). Anyway, the owner's manual says 90 octane for my truck. 'Course, being at elevation and the overall cleanliness of the gas may make a difference. I think our winter gas gets more condensation, also. Anyway, that is what it took to get rid of the pinging I was having. I wonder if the fact that we are burning unleaded fuel in vehicles made for leaded fuel changes the formula. I can't say I know much about leaded vs unleaded chemistry from a chemist's perspective, but I would just guess it plays a role.
red66toy
Supporting Vendor
40's were made to run on leaded fuel? ??? When did oil companies stop putting lead in US gasoline?
i think it has something to do with temperatures and the lead acting as a softening agent....i'm really not sure, haha i could be lying to you. All i know is that my '65 Mini cooper was made to run on leaded fuel so I put in hardened exhaust valve seats allowing me to run unleaded.
We run E-10 unleaded in everything, it's 90-91 octane and also cheaper. Burn between 6-7000 gallons a year and never had a problem with it.
Dave, if your reading 90 octane in the owners manual, look to see what kind of octane rating it is, I beleive 90oct in 1971 equals 87octane now, at some point the octane ratings changed. I know of no cruiser besides the UZJ(and not all years) that calls for anything but 87oct(as rated today)
I also recall at higher elevation you can run a lesser octane rating.....being I am at sea level I never paid much attention as to why.
John H
[quote author=IDave link=board=1;threadid=13500;start=msg124866#msg124866 date=1079922203]
Here we have the range 87, 89, 90 and 91. There is no question after trying them all, that my F engine likes the higher octane better. (Maybe that is why I get 18 mpg, like I did on my little excursion to the river yesterday). Anyway, the owner's manual says 90 octane for my truck. 'Course, being at elevation and the overall cleanliness of the gas may make a difference. I think our winter gas gets more condensation, also. Anyway, that is what it took to get rid of the pinging I was having. I wonder if the fact that we are burning unleaded fuel in vehicles made for leaded fuel changes the formula. I can't say I know much about leaded vs unleaded chemistry from a chemist's perspective, but I would just guess it plays a role.
[/quote]
I also recall at higher elevation you can run a lesser octane rating.....being I am at sea level I never paid much attention as to why.
John H
[quote author=IDave link=board=1;threadid=13500;start=msg124866#msg124866 date=1079922203]
Here we have the range 87, 89, 90 and 91. There is no question after trying them all, that my F engine likes the higher octane better. (Maybe that is why I get 18 mpg, like I did on my little excursion to the river yesterday). Anyway, the owner's manual says 90 octane for my truck. 'Course, being at elevation and the overall cleanliness of the gas may make a difference. I think our winter gas gets more condensation, also. Anyway, that is what it took to get rid of the pinging I was having. I wonder if the fact that we are burning unleaded fuel in vehicles made for leaded fuel changes the formula. I can't say I know much about leaded vs unleaded chemistry from a chemist's perspective, but I would just guess it plays a role.
[/quote]
Cruiserdrew
On the way there
My FJ40 uses el-cheapo regular and lots of it! I think all gasoline cruisers up to and including 1997 were built to run on cheap 3rd world gas. I always pump the regular and its no big deal. I remember some 85 octane in states at high altitude, and I think it has to do with the lower density of the oxygen in the air, meaning you don't need as much octane to prevent pinging.
- Thread starter
- #14
In Colorado, or at altitude, the Octanes for the different grades are 2 (85 vs 87) then at sea level. Not sure of the rationale, but it has always been that way. My 77 owners manual says unleaded only.
Hey Chase, Cruisers up to about 1979 could burn leaded gas. After a model of car gets a catalytic converter, lead is a big no-no - it toasts your converter. Gas in 1973 (the year they started the lead phase out) had 2-3 grams per gallon or about 2 oz of lead per 20 gallon tank. We pumped about 200,000 tons of lead onto the air per year! Over the next few years it went from leaded to low-lead until finally it was phased out of gas completely by about 1985, and since then, the average American's blood lead level has decreased by a bunch. So why aren't we feeling a bunch smarter? It musta been somethin' else! Fast food? Daytime TV? All TV? Now there's a poll to take . . . .
Fast food? Daytime TV? All TV? Now there's a poll to take . . . .
red66toy
Supporting Vendor
So would my early 65 40 run better with a lead additive? It has never given me problems running on 87 and infact I got 20mpg on one trip. I wouldn't start adding a lead additive but am just curious. Thanks.
85, otherwize knowen as the cheepest gas avalible.. im cheep!!! and my Cruiser gets like 8 or 9 to the gallon, Its like feeding a fat kid Dogfood
[quote author=Landpimp link=board=1;threadid=13500;start=msg124884#msg124884 date=1079924534]
Dave, if your reading 90 octane in the owners manual, look to see what kind of octane rating it is, I beleive 90oct in 1971 equals 87octane now, at some point the octane ratings changed. I also recall at higher elevation you can run a lesser octane rating.....being I am at sea level I never paid much attention as to why.
John H
[/quote]
All right, John. I'll bite on the octane rating change. What you say rings a bell in the back of my mind. The reason I went to a higher octane rating was that I developed trouble with pinging, and one of the fellas on the Pirate board recommended higher octane gas (actually, I think he said 94, but that isn't available here). The pinging cleared, but I did wonder if I got water in the tank at the time. I'll back down over the next few tankfuls, since you all seem to do well with the lower ratings. It seems logical that the FJ40 should burn about anything. After all, that is what the octane adjuster on the dizzy is for. And I do know that higher octane gas won't get you better milage, unless you are having a substantial running problem such as pinging/preignition.
I have heard it is good to have hardened valve seats if you do a lot of prolonged, high speed (is that an oxymoron?) driving on these engines, since they were designed for leaded fuel.
The one time I tried the lead substitute stuff, the running went to crap.
Dave, if your reading 90 octane in the owners manual, look to see what kind of octane rating it is, I beleive 90oct in 1971 equals 87octane now, at some point the octane ratings changed. I also recall at higher elevation you can run a lesser octane rating.....being I am at sea level I never paid much attention as to why.
John H
[/quote]
All right, John. I'll bite on the octane rating change. What you say rings a bell in the back of my mind. The reason I went to a higher octane rating was that I developed trouble with pinging, and one of the fellas on the Pirate board recommended higher octane gas (actually, I think he said 94, but that isn't available here). The pinging cleared, but I did wonder if I got water in the tank at the time. I'll back down over the next few tankfuls, since you all seem to do well with the lower ratings. It seems logical that the FJ40 should burn about anything. After all, that is what the octane adjuster on the dizzy is for. And I do know that higher octane gas won't get you better milage, unless you are having a substantial running problem such as pinging/preignition.
I have heard it is good to have hardened valve seats if you do a lot of prolonged, high speed (is that an oxymoron?) driving on these engines, since they were designed for leaded fuel.
The one time I tried the lead substitute stuff, the running went to crap.
Oh, yes, and while we are on the subject of gas, could someone knowledgeable weigh in on the topic of ethanol blends? I understand that they tend to cause leaner running regardless of octane rating. That might be good (if it is correct)for those of you who have trouble with overly rich exhaust measurements. Any harm in gasahol?
theferg
SILVER Star
Yup yup. I too be runnin' the 85 octane (here in Utah) 'cause I also am a cheap bastid...
-Ferg-
-Ferg-
