What Gas Octane do you use ?

[mastermason11]

Shhot.. When I took it from the dealer, the dealer was too cheap to put a full tank of gas, so I filled it up myself with 91 octane.. Next time, I will use 87.. Thanks guys...

[gazz]

In the UK all Unleaded Petrol has an octane rating of 95. In the US you seem adamant that you should use 87 not even 91, how does this compare with us having 95.

Not sure what I am asking, but does anybody understand the difference.

Also what else do people use around the world?

Thanks
Gary

[bigdementia]

<div class='quotetop'>QUOTE(gazz @ Aug 20 2007, 04:58 AM) [snapback]499028[/snapback]</div>

In the UK all Unleaded Petrol has an octane rating of 95. In the US you seem adamant that you should use 87 not even 91, how does this compare with us having 95.

Not sure what I am asking, but does anybody understand the difference.

Also what else do people use around the world?

Thanks
Gary
[/b]

That's because in the UK, you use the RON method of octane calculation. In the US we use the RON + MON method, which results in a lower calculated number.

[viking31]

<div class='quotetop'>QUOTE(Duane @ Aug 19 2007, 07:33 AM) [snapback]498599[/snapback]</div>

As per the owners manual. use only 87 octane. Anything higher and you will be wasting your money and could cause engine problems.
[/b]

Engine problems with higher octane? What problems?

Rick
#4 2006

[fred s]

<div class='quotetop'>QUOTE(viking31 @ Aug 20 2007, 12:46 PM) [snapback]499181[/snapback]</div>

Engine problems with higher octane? What problems?

Rick
#4 2006
[/b]

Incomplete fuel ignition causing carbon buildup, assuming that the ECU can't use the knock sensors (if they even exist in this engine) to determine optimum ignition advance.


Strongly doubt any actual engine damage would occur, but you could get less MPG if the engine isn't utilizing the higher octane to advance timing.

[DelerPrius]

<div class='quotetop'>QUOTE(Fred S @ Aug 20 2007, 01:13 PM) [snapback]499196[/snapback]</div>

Incomplete fuel ignition causing carbon buildup, assuming that the ECU can't use the knock sensors (if they even exist in this engine) to determine optimum ignition advance.
Strongly doubt any actual engine damage would occur, but you could get less MPG if the engine isn't utilizing the higher octane to advance timing.
[/b]

Knock sensors can advance timing?

[tripp]

It's not good for the emissions system. This is true in any car not just the Prius. I use 85 octane, but I'm at 5400+ feet so 85 is similar to 87 close to sea level.

[viking31]

<div class='quotetop'>QUOTE(Duane @ Aug 19 2007, 07:33 AM) [snapback]498599[/snapback]</div>

As per the owners manual. use only 87 octane. Anything higher and you will be wasting your money and could cause engine problems.
[/b]

Engine problems with higher octane? What problems?

Rick
#4 2006

[IsrAmeriPrius]

<div class='quotetop'>QUOTE(gazz @ Aug 20 2007, 01:58 AM) [snapback]499028[/snapback]</div>

In the UK all Unleaded Petrol has an octane rating of 95. In the US you seem adamant that you should use 87 not even 91, how does this compare with us having 95.

Not sure what I am asking, but does anybody understand the difference.

Also what else do people use around the world?

Thanks
Gary[/b]

I hope this helps:

Measurement methods

The most common type of octane rating worldwide is the Research Octane Number (RON). RON is determined by running the fuel through a specific test engine with a variable compression ratio under controlled conditions, and comparing these results with those for mixtures of isooctane and n-heptane.

There is another type of octane rating, called Motor Octane Number (MON) or the aviation lean octane rating, which is a better measure of how the fuel behaves when under load. MON testing uses a similar test engine to that used in RON testing, but with a preheated fuel mixture, a higher engine speed, and variable ignition timing to further stress the fuel's knock resistance. Depending on the composition of the fuel, the MON of a modern gasoline will be about 8 to 10 points lower than the RON. Normally fuel specifications require both a minimum RON and a minimum MON.

In most countries (including all of Europe and Australia) the "headline" octane that would be shown on the pump is the RON, but in the United States, Canada and some other countries the headline number is the average of the RON and the MON, sometimes called the Anti-Knock Index (AKI), Road Octane Number (RdON), Pump Octane Number (PON), or (R+M)/2. Because of the 8 to 10 point difference noted above, this means that the octane in the United States will be about 4 to 5 points lower than the same fuel elsewhere: 87 octane fuel, the "regular" gasoline in the US and Canada, would be 91-92 in Europe. However most European pumps deliver 95 (RON) as "regular", equivalent to 90-91 US (R+M)/2, and even deliver 98 (RON) or 100 (RON).

Wikipedia® [/b]

[prius2go]

surely it has knock sensors to use higher or lower grade?
how new is this engine design?