High Octane

[chessclubloser]

Hey,

What does the Yaris owner's manual say regarding fuel grade required for the car? I noticed the engine has a 10.5:1 compression ratio which is high and (in older cars) could require higher octane fuel. I'm guessing the manual says 87 octane, but is there anyone out there who puts in a higher grade regularly?

Just a side note, is there anyone out there who thinks the 'paint sealant' is worth the $400 or whatever your dealer charges?

[swng]

I have a Canadian 06 Yaris owner's manual in hand. Page 178 says "Select Octane Rating 87(Research Octane Number 91) or higher". I do not know what Research Octane Number 91 is but I have been using Octane Rating 87 fuel for more than two months and there has been no problem this far.

[GTBaker]

I notice my mileage increase a bit going from REG to Super.

[Why?]

Your mileage should increase if you use higher octane fuels. Almost all power and fuel economy tests are done on the highest octane fuel commonly available in the country.

For US this is 93.

The question is does the economy benefits outweigh the higher price.

[Tideland Prius]

10.5 isn't that high is it? I figured 11.5 and above would be the type that would recommend or even require premium fuel.

Also, is there a difference between 91 and 94?

[ToTo_17]

Here in Hungary, I usually use 95 octane fuel from Shell, its precisely the V-Power 95 gasoline. But we also have 98 octane and 100 octane Shell V-Power Racing!

[ST185]

Originally Posted by ToTo_17

Here in Hungary, I usually use 95 octane fuel from Shell, its precisely the V-Power 95 gasoline. But we also have 98 octane and 100 octane Shell V-Power Racing!

In Europe, they use RON (Research Octane Number) in stead of PON (Pump Octane number) like in the US. By the way, MON = Motor Octane Number and PON = (R+M)/2.
In the manual, 87 is for PON which is aproximately 91 RON.

[thebarber]

dont waste your money on high octane gas. the 10+ cents a litre you spend would have yeild at least a 10% gain in economy, which im sure you wont get. save some money, buy 87

[ToTo_17]

Originally Posted by ST185

In Europe, they use RON (Research Octane Number) in stead of PON (Pump Octane number) like in the US. By the way, MON = Motor Octane Number and PON = (R+M)/2.
In the manual, 87 is for PON which is aproximately 91 RON.

I have not heard of this before, thanks for the info!

[yariman]

Don't waste your money on higher octane fuel. It won't run any better or get you better milage.

[ToTo_17]

Originally Posted by yariman

Don't waste your money on higher octane fuel. It won't run any better or get you better milage.

Then you think its just a rip off, what is the priniple for it then?

[yariman]

The required octane rating of an engine is a part of it's design. Higher octane fuels actually burn slower and are used in engines that are designed to require it such as high compression engines where low octane fuels ignite too quickly and cause detonation etc. which damages the engine. It is a misconseption that higher octane fuels are " better" for your engine. If it runs fine on regular ( no pinging etc.) and the manufactorer recomends that grade, using a higher grade is just a waste of money. However there are engines that do need a higher octane fuel.

[thebarber]

i need high octane...11.5:1 compression ratio....

[ToTo_17]

Originally Posted by thebarber

i need high octane...11.5:1 compression ratio....

Then would I need it as well for my Yaris T Sport?