High octane gas

Just like in Switzerland, over here in the Netherlands 'normal' petrol has 95RON. There's also Super petrl that has 98RON. Does that mean when you talk about octane 87 you mean 95RON??? I checked out the link boa provided and 97RON is the same as 87MON.

 

The argument of premium vs. regular gas for the Prius parallels that of synthetic vs. regular oil. Neither premium gasoline nor synthetic oil is going to make a tangible difference in this car.

My father uses premium gasoline in his 87-octane rated car because premium basoline is "better". I have told him many times that he's throwing his money away, but there's no way to convince him... premium is better. At least he has not heard yet about synthetic oil.

 

jamarimutt, Give us his address so we can educate him on the wonders of synthetic oil too. :lol: :lol:

Seriously, the reason, I have started to use full synthetic oil is that it is not primarily derived from crude oil but made from alchol esters. I have no illusions about vast improvements over regular dino oil in performance.

 

87 octane petrol

Hi Batavier,
Also here in Finland the lowest octane rating is 95, and super is 98.

87 octane fuel is a mixture of alcohol and petrol. 10% of alcohol and 90% of petrol. It is also called "E10".

Today here in Riihimäki 95 octane was 1,16 Euros/litre.

Regards,

Heikki

 

I gather that some people use synthetic oil because they don't want to use dino oil. However, has someone seen a definite statement saying that synthetic oil contains no chemicals derived from petroleum?

On the subject of gasolines, a while ago they had on TV a program about the production gasoline. As I recall, gasoline production is a standard chemical process and there are no differences between brands until the very end, when just before delivery brand x adds a small amount of "secret additive y" in order to give their brand something distinctive. The additive may be a colorant, like in a brand of gasoline (I don't remember which, since I use generic gas) which is blue.

 

Look again, Batavier. It's clearly stated there

"In America the service stations use the Pump Octane Number or PON rather than RON. This is the average of RON and MON..."

Therefore US 87 is PON and equal to our 90 RON.

 

In aviation, the Pilot Operating Handbook is the law regarding what you can or cannot do to, or put into, an airplane. Same thing should apply to cars.
Since there are multiple recommendations in the "operating handbook" for the Prius, to use 87 octane fuel, what is the big issue here? You guys can go on for pages about the longevity of various parts of the engine; rpm's; burn rates; cooler vs hotter, etc, etc. Bottom line is that it's not only OK to use 87, it's recommended. Why would Toyota recommend something that, if followed, would only cost them hugely in warranty work?

 

Use 87 every oil change put in a bottle of the injector/fuel sys cleaner. with todays additives in the fuel and the once in a while bottle of "stuff" i can't imagine your injectors etc would be that dirty......

 

I heve been through this regular vs. high octane fuel debate in my Lotus club several years ago. What we did was to invite a representative from Chevron to one of our club meetings to settle the debate. Being one of those people that just loves to confirm information before accepting it as gospel, I went to a major fuel distributor in my area and had them comfirm that everything the Chevron engineer told me was completely accurate, so here goes:

Use the lowest octane rated fuel that your car manufacturer recommends. This is because higher octane fuel is designed to resist detonation (pinging) because it is significantly slower burning.
There is a bigger difference between brands as far as quality of gas goes vs changing grades of the same brand (regarding sulphur and detergent differences). That means that a higher quality brand name would probably give you cleaner burning uncontaminated gas compared to a no-name (or price is everything) brand.
If you want clean fuel injectors, buy the best gas you can afford (but stick to your correct grade ex: 87 Octane for Prius) and run a bottle of Techron through your tank once or twice a year.
There is no harm (damage) in using higher octane. There is definitely a reduction in fuel economy and reduced power (less energy per gallon in high octane vs. low octane) which sometimes can be very noticeable.
If you go too high in octane you get much higher emissions because not all the fuel will be burned (too slow a burn rate in high octane) and blows out the tailpipe.
Do not attempt to add napthalene to the gas. This is a very old technique that doesn't work now and isn't necessary. People did this because gas used to be low octane. This was done by throwing moth balls into your tank. The problem is that there is no scientific way to measure how much product you are putting in your tank, and most moth balls if not all of them are made of different materials now.

As for the Lotus question, I agree with Mark. I have owned Lotuses since 1985 (and still do). The Elise has a 10.5:1 Otto Cycle engine, the Prius has an 8.5:1 Miller Cycle (yes I know Toyota is calling it Atkinson Cycle - look it up : ). This is a huge difference in compression ratio. Even if we were to mistake the expansion ratio for compressoon ratio, a 13:1 compression ratio would require racing gas (at least this is true for the Lotuses that are raced in our club) so that obviously could not be true of our Prii since all the engines would experience severe detonation.

The moral of the story is to buy gas from name brands and get the 87 octane that Toyota recommends. Everything else is a waste and could potentially reduce mileage and increase pollution.

 

Thanks Gen2 for such a clear and concise explanation on octane. Hopefully, your explanation has clarified any questions on what is best to put into your Prius' tank!

 

You are misinterpreting. In the USA, octane is determined by
(Research octane + Motor octane)/2, also known as R+M/2. As stated, the 91 number is Research octane number only, roughly equivalent to the USA 87 octane number.

Remember the owner's manual is written for owners in numerous countries, then translated. Also, most owner's manuals include information so that if you use the vehicle in a different country than it was purchased in, you can understand the requirements for things such as fuel, coolant, oil, etc. that may or may not be readily available in other countries, or may be specified differently.

Finally, I would counter your longevity theory by reminding you that using higher octane fuel that is not completely burned during combustion results in more "crud" in the cylinder heads, combustion chambers, and exhaust system and helps foul spark plugs. In the exhaust system, this stuff accelerates the rusting out of your pipes and muffler. In the cylinder heads, this reduces power, efficiency, and may increase emissions. But as you say, it is your choice.

 

As far as I know the Prius Exhaust System is Stainless Steel, but all the other points are good. There is an exhaust effect for sure though. If there are excess unburned hydrocarbons going out, they will stress, overload (increase emissions), clog (backpressure) and possibly damage the catalytic converters.

There is the long Emissions Parts warrantee to help backstop you if they fail, but it's not outside the realm of possibility that if Toyota was aware that you were not using the recommended fuel, they might try to void the warrantee.

 

Randalla,

The pleasure is all mine. We went through this at the Lotus club and the argument went on for a few years until one of the members got smart and got help. Sort of like an intervention for a car club I hope that I covered enough material to satisfy eveyone's basic questions. If not, I would be happy to elaborate.

BobLo

 

So "buy gas from name brands"? Does Costco count?
Are some brands (ARCO tends to be cheapest) known to be better than others, or is this another big debate?

Thanks for the education!

 

DelRey,

You are welcome. Unfortunately CostCo predates when we performed our research. Arco actually worked well enough to not get many complaints, so it should be OK. Keep in mind that we were running some high-strung cars at the time so in many cases we were very sensitive to small qaulity changes in the gas.

Since the Prius is not high-strung at all (low compression ratio, etc) I think that if you stay away from Rotten Robbie (nearly everyone hated this gas) and the no-name brands you will probably have no problems.

We did find that if the carbs/fuel injectors were suspected of being dirty/clogged/whatever that either switching to Chevron for several tankfulls or using Techron often cleans up the problem.

Since using Techron regularly brings the cost of gas back to what it costs to buy from Chevron I just switched to Chevron and have had no problems in my cars at all.

Enjoy,
BobLo

PS Just a little tidbit I found on the web:

Shop around for the best quality, price and service:

Keep track of the miles per gallon and go to the station where the best value is received.

Do not buy more octane then you need.  Check your owner's manual for octane recommendations and purchase the lowest octane gasoline your vehicle uses without your engine pinging or knocking.  Once you know your vehicle's octane level, use higher octane only under stressful driving conditions such as pulling heavy trailers or boats.  Using too low an octane can cause engine damage.  Using too high an octane for the driving conditions of your vehicle will not give you more power or better mileage.

Find the brand of gasoline that works best for your vehicle.   Keep track of your miles per gallon.  Although almost all gasoline comes from the same pipelines, the additive packages differ greatly between brands.

Shop around for the best quality, price and service.  You've spent thousands of dollars on your vehicle so it makes sense to frequent a reputable location that provides you with good service.

Consumers who suspect they have received poor quality gasoline or an incorrect measurement should contact:

THE MICHIGAN DEPARTMENT OF AGRICULTURE MOTOR FUELS QUALITY
1-800-MDA-FUEL

 

Unfortunately, the last posts from either richard schumacher or sparkymarvin was June 21 7pm cdt, so it is unclear whether they have had a chance to reassess their positions on the higher octane gas in light of mdac's and gen2's postings.

 

Note: Richard apparently edited his post to remove a statement about Higher Octane not equating to slower burning, and a statement that he had not seen any 'proof' of statement made by people here, so my reply doesn't appear connected now, but I'm leaving it. I replied to what he said, not what he's saying now.

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Are you saying that you don't believe that Higher Octane = Slower Burn Rate?

That's one of the fundamental concepts of Octane ratings.

The fact is, that if you run High Octane gas in an engine designed for a lower octane, it is likely that you will have incomplete combustion.

This leads to

1) Lower Mileage
2) Lower Power
3) Increased Emissions (unless the catlytic converters catch it all).

If you need the word of someone besides the folks here:

http://www.state.mn.us/cgi-bin/portal/mn/j...agency=Commerce

Quote: "High octane gasoline burns slower than low octane gasoline."

You said there was no evidence that High Octane fuel leads to emissions system fouling. As I said earlier High Octane fuel is a known cause of Emissions Error Codes (and Dashboard Lights) on the Prius. If the Prius itself is telling folks that it is not happy, that's pretty good evidence to me.

I sincererly doubt that any benefit you are doing for the environment by using (possibly) lower sulfur fuel would be offset by the other effects.

Especially since the Prius Catalytic Converters are designed to take care of the emissions before they get out anyway.

Finally, if you search around, you will find innumerable reputable sources that say "Using High Octane Fuel in a car designed for Low Octane will not increase Mileage, Power, or decrease Emissions. If you use Higher Octane than the Manufacturer recommends, you are simply wasting money at best".

Those are easy to find.

Since you apparently question them, and the knowledge of the people here, it's fair to turn the tables I think.

If you believe all those sources are wrong, then please present the reputable 'citations' that support your belief.