88 octane

Since there is some confusion about what fuel the 2010 needs, here's my 2 cents worth.

There IS 88 octane fuel available....it is "plus" at most stations, and rated at 89 octane.

Just filled our second tank with "plus"....sometime next month we'll see if there is a difference.

But, with such a high compression ratio, it would seem the gas engine needs as much octane as the system is set for.

Around here with 10% corn juice, 87 octane is more like 85 or 86, my bet is the engine will run more efficiently on 89 octane, which is the functional equivalent of about 87 octane by the no corn juice calculation.

Costs approximately $1.00 more per tank full.

No, the 88 octane rating is a misprint in the manual.

Hi and :welcome:


This is a topic that has been discussed A LOT. And the 88 in the owner's manual is a confirmed typo - should have read 87. You can read a lot of the discussion here: http://priuschat.com/forums/gen-iii-2010-prius-main-forum/61874-88-octane-2010-prius-whats-up.html

I thought the compression ratio was a rather unexciting 8.5. The 13.0 number you see in print is an expansion ratio. Unlike a traditional Otto cycle engine, this is an Atkinson cycle engine, so valve timing allows the two figures to be different. And timing is also variable.

there really isn't any confusion - the six prior threads in PC dealing with this issue have made it clear

google "88 octane" prius and the first result is:

88 Octane for 2010 Prius - What's up with that? - PriusChat Forums
10 posts - 8 authors - Last post: May 19
It is being reported that 88 Octane or Research Octane Number 92 is required. I don't think the 88 is a misprint because normally the ...
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What fuel (Octane Rating) for Gen III ?‎ - Jun 27, 2009
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Please stop telling people to use 89 octane