Mixong 87 and 89 octane gas.

Ilpav

Ilpav

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I was filling up my car today and I always fill up 87, but my brother accidentally filled up with 89 (with still 1/3 of a tank of 87). Will this do any damage to my car?
 
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No - higher octane won't hurt. The only way you can do damage is if you run a lower octane than your car needs and the ecu is unable to adjust the timing to suit.
 
The other thing you need to worry about (from what I've heard) is switching from prolonged use of non-ethanol gas to ethanol blended gas.
 
Too late for that - everywhere in the USA is now blended with ethanol, up to 10%, to replace the now banned MTBEs.
 
87 and 89 octane ? Hah, never even heard of such things since I only use 98 octane fuel, some people use 95 since it is slightly cheaper, but only about 1-2?/tankfull.

They also offer 99 octane "special Ferrari" fuel, but that costs like shit and doesn't do anything unless you have powerful sportscar on a track.

Sorry for the off-topic.
 
Brother Michael said:
87 and 89 octane ? Hah, never even heard of such things since I only use 98 octane fuel, some people use 95 since it is slightly cheaper, but only about 1-2?/tankfull.

They also offer 99 octane "special Ferrari" fuel, but that costs like shit and doesn't do anything unless you have powerful sportscar on a track.

Sorry for the off-topic.
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Here almost everyone uses 95 octane and 98 is only used if the car is recommended to run on it or if its high performance. I tried a tank of Super Unleaded and TBH couldn't notice the difference so decided to save my 5p a litre.
 
Ilpav said:
I was filling up my car today and I always fill up 87, but my brother accidentally filled up with 89 (with still 1/3 of a tank of 87). Will this do any damage to my car?
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I read somewhere that using 87 all the time can really foul up the insides of your engine and make it run like crap. You might get better mileage with higher octane anyway. The minimum I ever use is 89.
 
Brother Michael said:
87 and 89 octane ? Hah, never even heard of such things since I only use 98 octane fuel, some people use 95 since it is slightly cheaper, but only about 1-2?/tankfull.

They also offer 99 octane "special Ferrari" fuel, but that costs like shit and doesn't do anything unless you have powerful sportscar on a track.

Sorry for the off-topic.
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The highest octane we have here in Canada is 91 and most sports cars use that.
 
You can find 93 around here, but very few gas stations cary it.

Now at the dragstrip we can get as high as 118, but that is leaded and not legal for use on the street (road taxes aren't paid on off-road fuel). It's also a bit pricey. The last time we sold it it was in the neighborhood of $8 US a gallon.

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Interesting find about octane ratings in the USA/Canada vs. Europe/Australia:

Wikipedia said:
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 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.
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Australia has 91, 95 and 98 RON. I use 95 because VW says I should and it gets me about an extra 80km per tank than if I used 91RON!
 
I don't think that's true for cars that are designed to run on 87. I only get 87 because that's what the manual recommends...

I hate people who buy high octane gas when their car doesn't need it because they think they get some kind of advantage.

KaJuN said:
I read somewhere that using 87 all the time can really foul up the insides of your engine and make it run like crap. You might get better mileage with higher octane anyway. The minimum I ever use is 89.
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Use what is recommended for your car. You won't damage your engine at all if you use a higher octane - you're just wasting money. In North America, service stations blend the higher octane (like a 92 or 93) with a lower octance (87) for the mid-range fuels (89-91) so you're really not getting your money's worth.

As far as the European fuel standards go, Craig pretty much summed it up. Take 5 points off Euro-fuel, and you get the equivalent NA standard. And no, a higher octane rating doesn't give you better milage.
 
Shawn said:
I don't think that's true for cars that are designed to run on 87. I only get 87 because that's what the manual recommends...

I hate people who buy high octane gas when their car doesn't need it because they think they get some kind of advantage.
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I don't use 98 bacause I think I get some extra umph, or something. I know I don't. The only reason for it is that everyone is complaining to me "Oh, it's so expensive, why do you buy it". It's a bloody 1-2? more expensive for a whole 60L tankful !!! If I fill up 4 times a month, that makes a saving of....WOW !!!! Almost 8? !!! Man do I feel stupid right now.

I also dislike people saying "uuu, I go much faster with me 98 octane". I use higher octane only and purely for principal based reasons.
 
I'm not sure how it is in Europe but here the difference is actually somewhat substantial. Plus it's not a money issue... even if it costs little more, why do it if there's no benefit? It's like getting a whole meal at McDonald's just because it's cheap, even if you only really want the burger to eat.
 
Brother Michael said:
I don't use 98 bacause I think I get some extra umph, or something. I know I don't. The only reason for it is that everyone is complaining to me "Oh, it's so expensive, why do you buy it". It's a bloody 1-2? more expensive for a whole 60L tankful !!! If I fill up 4 times a month, that makes a saving of....WOW !!!! Almost 8? !!! Man do I feel stupid right now.

I also dislike people saying "uuu, I go much faster with me 98 octane". I use higher octane only and purely for principal based reasons.
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Principle based reason being...to spend more money? At least the marketing departments of the oil conglomerates like you...
 
klutch said:
Principle based reason being...to spend more money? At least the marketing departments of the oil conglomerates like you...
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Well, no. I know nobody really gets my reasons but trust me, if you know some of my friends and relatives, you would probably do this too. It's kind of like a Greenpeacementalistperson would come up to me and say "Hey, did you know that by buying a petrol powered car kills the White Madagaskar flowerbat". You can be damn sure that I will buy the petrol powered car for that reason alone.

So yes, I am spending a tiny amount more money, but I just don't give a crap. I do this because I am an asshole. But at least I know I'm a self centered wiseass coldhearted piece of human lowlife, which cannot be said for the people who are counting their pennies at the store when thinking whether to buy a 0.98? or a 0.99? can of peas.
 
That's completely incomprehensible to me, but whatever, buy the more expensive stuff even if it does you no good. You obviously put a lot of emphasis on money since you keep bringing it up.

I have always lived a comfortable life financially but I can tell you that I wouldn't waste a few dollars to get the expensive gas. Just because you have money doesn't mean you should throw it away.

Still, you maintain that you understand the difference so I apologize for pressing the issue. Do what you want but don't try to explain it to more people because I promise few would understand your logic.

Brother Michael said:
Well, no. I know nobody really gets my reasons but trust me, if you know some of my friends and relatives, you would probably do this too. It's kind of like a Greenpeacementalistperson would come up to me and say "Hey, did you know that by buying a petrol powered car kills the White Madagaskar flowerbat". You can be damn sure that I will buy the petrol powered car for that reason alone.

So yes, I am spending a tiny amount more money, but I just don't give a crap. I do this because I am an asshole. But at least I know I'm a self centered wiseass coldhearted piece of human lowlife, which cannot be said for the people who are counting their pennies at the store when thinking whether to buy a 0.98? or a 0.99? can of peas.
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You guys all understand that an octane rating is only the fuel's resistance to detonation right? It has ZERO effect on any performance measures, and as already mentioned, running a lower octane forces your ECU to retard the timing because the fuel is burning too quickly (igniting to early in the stroke). If you run higher octane it has to advance the timing slightly, but for some reason it does not have to advance as far as it has to retard on the lower octane... go figure!
 
Scott said:
It has ZERO effect on any performance measures, and as already mentioned, running a lower octane forces your ECU to retard the timing because the fuel is burning too quickly (igniting to early in the stroke). If you run higher octane it has to advance the timing slightly, but for some reason it does not have to advance as far as it has to retard on the lower octane... go figure!
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The change in timing does have an effect on performance though (how noticeable that is will vary though). I have to run 95 or 98 in my car as I've advanced the timing - it will ping on lower octane, but I like the extra little bit of responsiveness I get.
 
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