Using 91 Octane on mine...

 

Mr. Medic and I definately notice a performance difference when we get "crappy" gas. So much so that hubby (when home) often puts an octane booster in the tank with each fill up, and I have taken to doing the same.

I went about six fill ups without it (out of laziness and never picking any up)while he was gone, and it seemed to be "running hard". When he came home on R&R, the first thing he did was throw in an octane booster, and she ran much, much better and quieter. The difference is literally audible. We have ALWAYS used the "premium" top grade fuel, but as you probably know the quality of so called premium fuel varies from gas station to gas station. It works my nerves that we end up adding that booster to what is supposed to be the best fuel, but it is what it is.

(Side note: I was livid after we bought the thing for that reason ONLY. We didn't ever think to look inside the gas cap when we test drove it and bought it. Two days later, when he went to fill up, I heard my husband yell *&$#@%*&!!!! when he discovered the words "Premium fuel only" inside the cover)

I try to justify it by telling myself that if we can afford the FJ, we can afford to fuel it properly, but at this point, I've considered selling our oldest to the circus to offset the price of gas.

 

here's the answer

Toyota FJ Cruiser Forum - Search Forums
:cheers:

 

There's a bulletin from Toyota correcting the premium only statement. 87, 89, or 91 they will all be ok. Run what you feel works best for you.

 

There's a bulletin from Toyota correcting the premium only statement. 87, 89, or 91 they will all be ok. Run what you feel works best for you.

 

Premium all the time. For the couple dollars more why not.

 

87 octane, 97% of the time. I've done comparisons running multiple tanks of regular vs. premium and found it more economical to run regular. The very slight increase in mpg using premium does not offset the higher cost. JMHO

 

I've seen the scanned picture of the bulletin, but does anybody have a link to where I could find this officially on Toyota's website? I never received any bulletin, just wanted to verify the validity.

 

It was an internal communication to the dealerships, it's not on the Toyota website (note the comment in the bulletin regarding the brochure and website)

If you are questioning it's validity, I can offer you no further help. It was delivered to the dealerships 2 days before the original launch date for the FJ Cruiser.

 

Rover, I'm not doubting you, it just seems like there are always conflicting stories on this one. Thanks for the help!

 

There are conflicting stories regarding a lot of things, it's up to us to look things over with a discerning eye.

Remember, most of the advice you get on an internet forum is worth exactly what it cost you.

 

50% 91-93 and 50% beer.

 

I always use 91 but i might start using lower octane after reading this to save some $$$

 

Normal driving 87... i add some seafoam every 5k or so. Then 91 from either shell or exxon while wheeling

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Leaded? RLY, you're asking this?

What car made in the last 40 years has recommended the use of leaded fuel?

 

91 since day 1, I had to use half a tankl of regular because that was all the samll town gas station had. Could tell right away - the FJ was none to pleased with it.

 

I've always used 87, but 2 weeks ago the local Valero had 89 for only $0.03/gal more than 87 (no idea why, maybe an error in their system). So I jumped on it and really didn't notice a difference, until I went back to 87 on the next tank. Then I realized just how much difference the 89 made. I'll soon be buying a small car for daily commuting, so I'll probably start using 91-93 in the FJ since I won't be driving it much.

 

93 Exxon or Shell since day one and not planning to change that. I did try regular, truck definitely didn`t like it. Maybe with 6MT difference is more pronounced, i don`t know

 

87 for me
reset the ECU and tried 4 tanks of 93 with no noticeable increase in mileage or performance.

 

I use premium it is not that much more expensive and a lot cheaper than adding octane booster. Which doesn't usually amount to much of an octane boost unless you spend a whole lot more.

With the high gas prices it is cheaper (as a percentage) to run premium than it used to be.

Ex Premium - $4.20 reg $4.00 gal
4.00 / 4.20 = 4.76% higher to run premium

When gas prices were "reasonable"

premium $2.10 regular - $1.90
1.90 / 2.10 = 9.047% more to run premium.

So as a percentage the cost to run premium vs regular has actually decreased.

Still about $3.00 more a fill up though...but I do get slightly better gas mileage so that offsets it too. Based on a 4 tank fill up comparison, just over 1 mpg better. 16 gallons x 1 mpg = 16 extra miles, which is .76 of a gallon for me (21 mpg). .76 x 4.20 = $3.20 savings, which completely offsets the increased cost.

JMO

 

I personally use Premium. If you happen to have a Liberty gas station near you, their Premium price is comparable to the Mid-grade of the others (BP, Sunoco, etc.).

I have a 2010, which uses the newer Dual VVT-i technology. According to Wikipedia, using 91 octane fuel provides a 20 hp boost over using regular. I personally find it hard to believe, but since the difference in price is negligible, and it personally feels faster on my butt... I go for premium all the time. The fact that some find it helps in fuel economy only solidifies my choice.

I'm sure that if I did a blind "taste test" where someone else was filling up my FJ and I didn't know which tanks were premium and which were regular though, the butt dyno would probably provide mixed results. But for me, the price difference is small enough to just take the plunge and hope for the best.

 

In my 07, I alternate regular and premium every other tank but would be running regular all the time if I didn't believe the hype about 07-09s needing premium.

 

All other things being equal, higher octane gives better performance if the motor can take advantage of it. There are other factors to consider that are difficult or impossible to account for. Ethanol content lowers performance, no matter the octane rating. Stations don't post ethanol content. They might say 'at least' 10% or something else, but you never know the actual percentage. If you find a station that uses no ethanol additive, USE IT! You will be happy with performance if you romp on it. You will be happy with mpg if you have a light foot.

 

Ethanol content lowers performance, no matter the octane rating.

This part is not true. Ethanol actually increases the effective octane rating of the fuel and gives higher performance. Flex-fuel vehicles get more HP and torquer using E85 vs. normal E10. But the fuel has a lower energy density, so you get lower MPG using it. Some engines, especially older engines, may run better off pure gasoline than E10, but this is for other reasons.

And while stations don't post ethanol content, unless you are getting ethanol-free gas, all pretty much all commercial gas is E10. Depending on the specific blend it may be E8 or E9, but ethanol is cheaper and raises the octane rating, so refineries use as much as they can.

And for those using premium, that is almost guaranteed to be E10, as ethanol is an octane booster.

 

I've heard through the grapevine that Shell uses less ethanol and I have had some all time high mileage fill ups from Shell. All gas now has ethanol as well, just differing amounts.

 

Interesting, I usually lean towards big name stations but I had one of my all time lows from a Shell. I should have know better as it was a full $.20 cheaper than any station in town.

 

I use whatever is the lowest octane rating available. Usually 86, sometimes 85. I have never read any convincing scientific evidence that running premium gas gives improved mileage in a car that's designed for running regular.

The only exception would be if I knew there was ethanol free gas available - I'd use that one.

 

But a car designed to run on "regular" is different than a car designed and tuned to run on 91. For sure there is absolutely no advantage to running premium in an engine designed for 87 octane. Just a waste of money.

But in an engine that is designed to run on 91 for optimal power and torque, there is a difference. The VVT on the FJ engine will retard timing as needed for lower octane but it will be at the sacrifice of optimal performance. Optimal performance is with the timing advanced as Toyota designed and tuned this engine, which is achieved with higher octane fuel.

Granted in my 8 fill up comparison there are known variables and unknown variables. A big unknown is the content of ethanol in the 87 octane compared to the content of ethanol in the 91.