2008 Package 3 Premium or Regular unleaded

Welcome to PC and congratulations on your new car. Always use regular unleaded 87 octane gasoline. When the manual refers to premium it means quality (name brand) gasoline, not higher octane gas. It is possible to get 86 octane gas in some areas but this is not recommended. You do not need to pay extra - I use whatever no-name regular gas is the least per gallon in my area. Have fun driving!

 

<div class='quotetop'>QUOTE(Neicy @ Oct 4 2007, 02:18 AM) [snapback]521039[/snapback]</div>

We use Costco gas mainly and it works very well. We have never had any issues. I know that Hess and Sunoco are also very clean if you have that available where you are.

 

I think the term "premium" is used to indicate from a quality supplier rather than octane rating. Use 91RON or standard unleaded or E10 which here is 94 - 95RON with no adverse affects.

 

As I understand it, for any car you should use the lowest octane gas that doesn't induce knocking. So, if you experience knocking, you need to move up the octane ladder until it goes away.

Additionally, as I understand it, higher octane gas doesn't offer a significant MPG increase. So basically this means that one should use the minimum octane that doesn't knock. I believe this would be 87 octane for most Prius owners.

 

<div class='quotetop'>QUOTE(SOCOM @ Oct 4 2007, 02:04 AM) [snapback]521037[/snapback]</div>

If you want to be picky, check out:

http://www.toptiergas.com/

Otherwise, any 87 octane fuel will work just fine. You're just wasting your money if you buy a higher octane fuel.

 

<div class='quotetop'>QUOTE(redryder @ Oct 4 2007, 11:29 AM) [snapback]521294[/snapback]</div>

+1 on focusing on using a high quality detergent gas. I was personally surprised that an engine with a 13:1 compression ratio could run on 87 octane gas, but I have been running Chevron regular for just under 5,000 miles with no problems. My MINI throws a major fit if it gets anything less than 91 (and it really wants 94-95 in the summer). Direct injection does seem to reduce the octane requirements.

 

In my previous posts I refered to 91 RON petrol which I believe is the same as 87 octane in USA.

Prius only has a 13:1 compression ration in theory, in the Atkinson cycle which leaves the inlet valves open for a part of the compression stroke so some of the air/fuel goes back into the inlet manifold to wait for next cycle. This means the engine doesn't compress the charge for a full stroke using less power to compress the charge, however power is produced over a full power stroke. This is why the Atkinson cycle engine is more efficient than an Otto Cycle engine which is the type of engine in most cars. The crankshaft is also not aligned with the centre of the bore which contributes to engine efficiency.

 

True for older engines but not for most recent ones. If a Prius engine starts to knock or ping (not to be confused with the normal shuddering that often happens for a few seconds after starting or stopping) then it needs repair, not higher octane gas. The exception is operation at high altitude, above a few thousand feet. That *does* need higher octane gas.

 

<div class='quotetop'>QUOTE(richard schumacher @ Oct 5 2007, 04:10 PM) [snapback]521904[/snapback]</div>

Even cars that SAY they need higher octane usually don't. A friend of mine had a 2003 turbocharged Passat that 'required' 91 octane. I asked her if having to put in 91 didn't bust the budget since it is at LEAST 20 cents a gallon more than 87. She said she always used 87 and never had a problem or a ping.