newbie: gas and oil

I join in stock's request re: type of oil.

 

87 is just fine. There is some consensus that a higher octane may have negative effects but I have not seen any evidence that it would do any harm to anything other than your wallet. Use whatever oil you like, just change it regularly and you will be OK. I am personally using Mobile 1 in my Prius with Purolator Pure One oil filters.

 

In normal operation, a gasoline engine uses a precisely-timed spark from a sparkplug to explode the fuel-air mixture compressed by the piston in the cylinder. If the fuel-air mixture explodes spontaneously on the act of compression alone, this throws off the timing and causes engine knock.

Higher-octane gasoline resists this spontaneous explosion under compression better than lower octane, which is why high-performance sports car engines with high compression ratios need high-octane fuel for smooth operation and to prevent engine knock.

The Prius engine is not a high-performance engine. It does not compress the fuel-air mixture anywhere near as hard as in a sports car engine, which is why 87-octane regular unleaded works perfectly fine. In fact, the Prius manual specifically says not to use higher-octane grades.

 

the only benefit of high octane blends is that most gas stations also throw in their premium additive package of cleaning agents. If you are concerned about not getting enough cleaning additives to keep your engine clean just dump a bottle of $5 Techron (in the gas tank) at every oil change. Easy to remember that way.

By the way just use Synthetic, there is lots of evidence that supports that you get better gas mileage, it lasts longer, and the increase in cost on the Prius is minimal.

Cost of 3 oil changes (15,000 miles all most people need in a year)
$45 for Dino Oil (2 - 5 gallon jugs of name brand oil at Wal-mart + 3 mid priced filters)
$62 for Synthetic (2 - 5 gallon jugs of name brand synthetic + 3 mid priced filters)

 

87 is specified by Toyota.

There have been a few who reported signficantly improved mileage with higher octane or who had occasional ping or knock. These latter were in hot/sea level conditions if I am not mistaken. Mostly folks report slightly reduced mileage with higher octane in the Prius.

My opinion is that if you suspect you have a problem with gasoline, using a known high quality supplier is the first step. The second step is trying a higher grade. All 87 is not created equal since various components (including ethanol) are used to reach 87. Shell has a reputation as being a good high standard fuel to test against if you suspect the gas you are using might be the culprit.

If you get a large jump in mileage using higher octane then it might indicate an issue with the car.

 

I hope Toyota has tuned properly spark ignition as here in Spain we only have 95 & 98 octanes gas in our stations...

Does anybody truly now whether it could damage engine or not?

 

Europe uses a different method for figuring out Octane ratings. In Europe the Octane rating is calculated by using the RON while in the USA and Canada it is calculated by (RON + MON) / 2. Because the difference in the RON and MON ratings is about 8 - 10 points difference the same 87 Octane gasoline in the USA is equivalent to about 91-92 Octane in Europe.

 

? would any "damage" occur to the engine if one was to use 89 octane-since the vehicle is driven in Las Vegas heat. In past vehicles 87 octane resulted in valve knocking etc. in vehicles I've owned. With my current Buick GN (and recent SS Camaro) it was a given to use 91 octane. Also quality of 87 varied even from most 'brand' name gasolines-in my opinion. Any suggestions ?

Also I plan to use my free oil change at dealership at 5000 miles. I had planned to change oil at 7500 miles (myself) and switch to Mobile 1 and Toyota filter. Is the engine at 7500 miles considered broken in ?

 

Different cars, different requirements. I'd bet a dollar that your past cars did not have Atkinson cycle engines. Use what the Prius Owner's Manual recommends.

The Prius engine, drive system and brakes are broken-in at 600 miles.

 

Thank you for the clarification, but there is still difference value.

 

At 3500 miles had the first oil and filter change in my Convertible Prius. Choice was Mobil 1 5W - 30 and matching Mobil Filter M1103 for package 6, touring Prius. The results show nominal increase in mpg, after additional 1,500 miles driving local/highway, must qualify as limited results, in gas mileage to 41 mpg, prior was 38-40 mpg.

Use exclusively in Southern California, Valero Grade Premium 91. Prius manual states " Premium unleaded gasoline with an octane rating of 87 (Research Octane Number 91) or higher required for optimum engine performance." And " If you use gasahol in your Toyota, be sure it has an octane rating no lower than 87."
Note the words Toyota uses, Research Octane Number 91 or higher for optimum engine performance.

Valero is one of a select few companies available in the West Coast market that does not import Mid East oil. Another available gasoline in SOCAL market is ARCO that imports no Mideast Oil.

My preference to use a gasoline that cuts down depedence on foreign oil. Some may argue since I spent considerable money doing conversion to convertible, my viewpoint is hypocritical to spend added money on an extensive renovation for some would call vanity as well as still using an Exxon/Mobil product, a company who imports 130 million barrels of oil into US.

My way of thinking is, I still have a Prius that gets superb fuel economy using gas and oil products believe that best improve further the quality of the ride, drive and use of the car with the added pleasure factor of convertible component.

exproducer

 

You won't "damage" the Prius engine using higher octane fuel. You also won't get any benefit, unless emptying your wallet sooner is one.
You -will- get slightly poorer mileage with higher octane fuel in the Prius, though I doubt you could measure it reliably and repeatedly. It's in the range of 5% lower with 89 octane rated fuel, and 7% lower with 92 octane rated fuel. These numbers are based on long term tests, and even they may be subject to variables that will swamp the reading differences. So don't quote me.

I use 87 octane rated fuel, and prefer the stuff with -some- ethanol in it ("Up to 10% ethyl alcohol added"). It burns cleaner and automatically removes any liquid water from the fuel system.

I use Mobil 1 5W30 oil. When I switched to it there was no noticeable fuel economy improvement. I just use it because when it's -40C ambient there is less wear on the system when it tries to start the ICE. It IS a lot more expensive than "normal" oil. About 2-3 times more.

 

Gas = put regular in when you get down to 1 or 2 pips
Oil = Change every 5,000 miles

See Owner's Manual for details.

 

This is where it is worth remembering that gasoline pumps in the USA do not generally display the Research Octane Number, but the average of the Research and the Motor octane number (which is lower), that is, (R+M)/2 which you should see if you look closely at the label on the pump.

If you want gasoline with a RON of 91, look for a pump labeled "87".

-Chap

 

Rae-Vyn : When you guys say I use Mobil1 5W30 does that mean it's regular oil or synthetic?
If it costs 2 or 3 times more then it must be synthetic right?

Also when using synthetic do you need to do oil changes at 8000km or later since it's supposed to last longer?

 

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David,

Were are the long term tests you reference??

TIA!

 

Mobil-(1) is synthetic, not to be confused with Mobil Clean 5000.
While you are still in warranty it is still best to follow the manufacturer's recommended maintenance schedule just in case you needed warranty service (keep your reciepts and sign your maintenance book).

 

For warranty purposes you can't assume a longer oil change interval when using synthetic. The oil won't break down but it still accumulates combustion products and water, and oil changes flush these out. If you pay for a used oil analysis each time you can get away with a longer change interval, but if a warranty issue arose I would not assume that I could win an argument with Toyota about it.