Premium Gas and Better MPG

I live in California. Our choices of gas are 87,89, and 91 octane. Lately I have tried running premium 91 in my truck. Right away I noticed slightly better power going up the incline stretch of highway on my normal commute. I also noticed that my tank lasts a little longer. I am currently documenting my mileage on my most recent fill up for a comparison. Anyone else try running higher octane in their 4cyl? I don't think its all in my head. I really do feel a slight difference in the way the truck runs.

 

The only modern vehicles that benefit from premium fuel are those that are designed for it and require higher octane. Otherwise you're pooping money away.

 

You get 3 more HP from premium according to toyota.

 

I read all kinds of myth busting articles about octane. I understand that higher compression engines only benefit from premium gas. It is supposed to reduce knock. But, I wonder if premium gas here in CA has something else in it that makes the truck run better.

 

No.

 

Patchouli oil maybe?

 

LOL...that's Northern California gas...down here in SoCal we get organic, gluten free 91 octane.

 

Not only that, but California puts more shit into their gasoline than they put gasoline in their gasoline. Emissions FTW

If you want good gas, go to Oregon. Mind blown.

 

Please post a link to this...I'm curious since that goes against everything I've ever read on the subject.

 

Octane rating has nothing to do with the energy content of fuel, just its resistance to preignition. However, a vehicle might see an increase in mpg if it's not running quite as efficiently as it could with the lower octane fuel but the inefficiency is not being noticed in everyday driving. You also could see a difference in mpg if the mid-octane gas had ethanol in it but high-octane "premium" gas did not, or if one was left-over winter blend and the other summer blend, etc.

Altitude effects the need for higher octane fuel too, which is why some of the "mountain west" states can get by with selling 85 octane gas.

 

On the 2.7, I doubt it. On the 4.0, maybe.

We have 93 here and the engine sounds smoother to me on 93. Gas mileage is about the same, though, and I can't tell if there's a difference in power.

Somewhere on the TRD site, the 4.0 is quoted as making a little more power on premium. Through 2007, the manual said 91 or better was recommended. In 2008 they took that line out. Not sure if they changed something to make it a moot point or if they thought a line like that would hurt sales.

 

I dunno.. I know I've personally heard more people than I would ever guess saying "this is a really nice car because it has to have premium gas."

 

Not exactly. What is says is that 87 octane (research octane 91) is recommended. The octane rating shown on American gas pumps is (R+M)/2, which is the average between research octane and motor octane, which are two different ways of measuring the anti-knock property of gasoline, with motor octane being a much lower number than research octane. The reason that they included the research octane number is that it's commonly used internationally.

The Wiki explains it pretty well:

http://en.wikipedia.org/wiki/Octane_rating

 

http://en.wikipedia.org/wiki/Toyota_GR_engine

But for the lazy:

 

You can still search around the web, all the numbers are the same:

http://www.trucktrend.com/2008/99/toyota/fj-cruiser/base-sport-utility/349/

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If my work didn't block the site I would build one on their website and find out. 3 horsepower is nothing anyway, these trucks have about 200 to the wheels NA, 3 crank horsepower is probably 1 WHP and I wouldn't spend the extra for premium for it.

 

Wiki information is usually either supported by citations or includes a caution to the reader regarding an uncited source. If you think that the author has no idea what he's writing about then feel free to research the subject for yourself. Also, if you think hard-copy encyclopedias are any better then you haven't read many. Encyclopedia Britannica and other big-names have been known to re-publish the same false information for years on end. For instance, the article on the Salem Church Dam on the Rappahannock River in Fredericksburg, Virginia was re-published for 20 years, even though no such dam ever existed.

 

Here is what one of the leading oil companies says
http://www.exxon.com/octane-rating

 

That's basic info.

 

The Wiki cites a Toyota technical document, which is probably where they got their information. Unfortunately, to access the document database requires a username and password. The information is so specific and complex that I doubt that it's made up, I mean what would be the point?

If you have an account:

https://mytechdoc.toyota-europe.com...-europe.com/mytechdoc/j_spring_security_check