What octane for FJ

[MS3820]

My friend just bought an FJ Cruiser and he just read where he needs 91 octane. Are you owners all using the 91 Octane in your trucks. If not could there be long term issues?

[Spotter's Wife]

I always use premium in mine.

[gnob]

92

toyota calls for 91 for a reason.
high compression and hotter running.
and you save a whole $3 going to regular...

[MS3820]

thx I will relay the message.

[steveh]

RTFM !!!!!!!!!!!!!!

[dwkremer]

You need to use the 91. If you you could develop a knock.

[robertd]

I have been running 87 for months and no knocks, pings, or other problems....

[vaud]

Originally Posted by steveh

RTFM !!!!!!!!!!!!!!

Actually in this case the manual had an error...

[12_Volt_Dave]

I use 87 exclusively and have towed my trail rig over the Tehachapi for the Hammers without so much as a ping or knock. The only drawback to using 87 is that you will not get the full advertised horsepower. Like the tech bulletin says....no big deal.

[trkklr77]

ALL efi and "new" vehicles say that they "need" 91 or better. its b.s. and your rig, any rig will run fine on 87.


now i do notice a markable decrease in mpg in my 01 vw wagon, 26-27 on 87 and 30-31 on 91

[gnob]

well the 50 miles youd lose using regular costs you more than the additional $4 on fill up

say on 87 octane 13 mpg x 19 gals = 247 miles
say on 92 octane 16 mpg x 19 gals = 304 miles

difference of 50 - 60 miles even at 15 mpg thats 3 to 4 gals and at 3$ a gal thats 9-12$

fillup diff of 0.20 per gallon 19 x 0.20 = $3.8

gee its totally worth the $4 you save at the pump for the $12 you lose out tha back door

cheap ass jokers


i run 92 in my POS 22RE for the same reason
doesnt anyone remember the days of 101 octane...it would sure be nice if the assholes would let us have some decent fuel back. or better yet come up with something better than the allmighty 25% efficient gasoline

[vaud]

You only get the benifit of higher octane gas in an engine that's built to use it, ie, higher compression. Modern high compression engines you can usualy go to a lower octane without knocking because the computers will adjust the timing for you, at a cost of lower horsepower. But taking an engine that's low compression and built for 87 won't get you a dang thing runing 91 or even 101.. Remember, higher octane gas burns SLOWER, not faster.. lower octane gas burns faster. Higer octane prevents preigntion in high compression engines by burning and igniting slower. It's the higher compression of the engine running 91 octane that gets you more power, not the octane itself. Octane does not=more power by itself.. The most you could do with high octane in a normal engine is advance timming a bit, but you are not going to get anywhere near the power increase of a higher compression engine built for 91 or even race enignes built for 100+. You are wasting money running 91 in anything but an engine that is built for higher octane.

But your formula is basicaly correct.. higher 91 octane in the FJ which has an engine that is built for it will get you optimum power and range. If you run 87 the computer detunes the engine to prevent preignition/knock with the faster burning gas, but as a result you get less power and less range - as stated in the memo from toyota "Shows a rating of 239 HP which was achived using premium unleaded fuel - please note that this rating may be reduced using non-premium fuel"

Older cars can not adjust their timing computers as much if even at all so they were much more sensitive to the octane. A high compression power engine could not be run on lower octane without it being manualy detuned for it...

[12_Volt_Dave]

Originally Posted by gnob

well the 50 miles you'd lose using regular costs you more than the additional $4 on fill up

say on 87 octane 13 mpg x 19 gals = 247 miles
say on 92 octane 16 mpg x 19 gals = 304 miles

difference of 50 - 60 miles even at 15 mpg thats 3 to 4 gals and at 3$ a gal thats 9-12$

fillup diff of 0.20 per gallon 19 x 0.20 = $3.8

gee its totally worth the $4 you save at the pump for the $12 you lose out tha back door

cheap ass jokers

50 miles lost using 87?
Where did you get you numbers from? I'm getting 17 or better on 87 octane.

If what your saying is true then I'll switch to 92, but I'm just not finding it to be true in my limited search on the topic: (read 2nd paragraph in the first link)
http://ask.cars.com/2007/07/premium-gasolin.html

http://www.ftc.gov/bcp/edu/pubs/cons...tos/aut12.shtm

Just for the hell of it I'll run a few tanks of 92 through to see if it works.

I'm not a cheap ass joker, I just don't like paying extra if there's no benefit. Besides, based on your calculations you would be the cheap-ass joker in this scenario since your actually paying less per mile than I do...

[Simon]

I've filled my FJ with premium exactly once in my 14 months of ownership and on highway get about 19-20 mpg if I keep my foot out of it. No pinging, etc.

The one time I did use premium, the difference in power was not perceptible.

Simon

[gnob]

Originally Posted by 12_Volt_Dave

50 miles lost using 87?
Where did you get you numbers from? I'm getting 17 or better on 87 octane.

If what your saying is true then I'll switch to 92, but I'm just not finding it to be true in my limited search on the topic: (read 2nd paragraph in the first link)
http://ask.cars.com/2007/07/premium-gasolin.html

http://www.ftc.gov/bcp/edu/pubs/cons...tos/aut12.shtm

Just for the hell of it I'll run a few tanks of 92 through to see if it works.

I'm not a cheap ass joker, I just don't like paying extra if there's no benefit. Besides, based on your calculations you would be the cheap-ass joker in this scenario since your actually paying less per mile than I do...

it was just an example, i dont know the real numbers, my manual cruiser pulls down 15-18mpg on 92 octane.
i dont run regular simply based on the fact the 4runner runs like shit on it.
you definately drop mpg on lower octane.
i just was trying to prove a point, that when you think youre saving you arent always saving.
buying shitty gas cost more than just mileage, it creates extra wear on the rig, doesnt burn as clean which leads to build up, lost power, and eventual burnt valves etc.
regardless of what that bulletin says, toyota recommends it for a reason.

and even if you drop only 1 mpg on 19 gallons thats 19 miles, equates essentially to one gallon or the three bucks you thought you saved on the front. and my peace of mind is worth at least 3 bucks

[MoSun]

Originally Posted by gnob

92

toyota calls for 91 for a reason.
high compression and hotter running.
and you save a whole $3 going to regular...

Toyota recomends 91 octane because that was the fuel used when the engine was dyno tested. You can use any grade of regular gasoline with a minimal loss of HP. or Torque. They recomend 91 to meet published fugures.

[bigtarget]

I work in a Toyota auto plant, this was what an engineer told me. The FJ Cruiser engine/power train is basically the same as the one in the Tacoma and 4-Runner, a 4.0L V6 bolted on to an auto or manual trans. So why do the 4-runner and tacoma require only 87 octane? Simple, they were introduced before the 2007 model year as new models and therefore Toyota didn't care if they where LEV II standard complient, the FJ however does have LEV II certification, but the only way it can do this is on 91 octane. Both engines have the same compression rating 10.0:1 so the "higher comprssion" argument goes out the window. So it's either 239 hp @ 5200 rpm or 236 hp @ 5200 rpm. Torque is 278 lb/ft @ 3800 rpm or 266 lb/ft @ 4000 rpm. Using 87 WILL NOT harm your engine. My FJ has been drinking 87 for about the last 3 months and I've seen no major difference in milage. My right foot is always the reason it drinks too much. So if you want the extra power put 91 in, want to save at the pump 87 is fine. Hope this helps!

[Dustpark]

With 87 you get pre ignition. Pre ignition is what makes engine ping. Octine is a inhibitor. Higher octine allow the piston to get to optimum extention.

[TJnPROGRESS]

filled up last Fri, got 18mpg using 87