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Discussion Starter #1
Hi,

We've had our EX-L for about a week and Saturday I filled it with gas for the first time. I guessed that 89 octane would be OK; so, that's what I used. Should I go higher (93) or lower (87)?

Thanks
 

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87 is all the vehicle needs.

Putting higher octane fuel in your CR-V will do nothing other than waste money, it has been proven and discussed to death.
 

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Hi,

We've had our EX-L for about a week and Saturday I filled it with gas for the first time. I guessed that 89 octane would be OK; so, that's what I used. Should I go higher (93) or lower (87)?

Thanks
Sorry, but I can't help but mention this. You bought a new car a week ago and have not yet cracked the owner's manual?
 

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the "octane horse" has been beaten to death and back, revived, beaten, raped, sent through mental rehabilitation, forced into prostitution, then beaten again. please somebody make a sticky thread about octane numbers and what octane means, to refresh your memory it has nothing to to with performance, just the fuels ability to handle compression with out misfire. only high compression motors need mid or supreme. unless otherwise posted on your dash or on the filler cap that says "supreme fuel only" get 87 (normal). most gas companies will put some fancy sticker on the pumps that will make you want to put the high test in.
 

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Discussion Starter #6 (Edited)
Sorry, but I can't help but mention this. You bought a new car a week ago and have not yet cracked the owner's manual?
Not yet. But even if I had and the manual would have suggested the lowest octane gas, I still would have asked here for the forum members' real world experiences, i. e., the straight poop.
 

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Discussion Starter #7
...please somebody make a sticky thread about octane numbers and what octane means, to refresh your memory it has nothing to to with performance, just the fuels ability to handle compression with out misfire. only high compression motors need mid or supreme. unless otherwise posted on your dash or on the filler cap that says "supreme fuel only" get 87 (normal)...
What about the addition of 10% ethanol like we have here in FL? There was thread here:

http://www.crvownersclub.com/forums/showthread.php?t=3266&highlight=octane

in which one poster said that "[p]ure gasoline has a heat value of 20,750 BTU/lb while ethanol has a heat value of 12,810 BTU/lb. There is less energy in a gallon of 10% ethanol diluted fuel so it takes more to move our Vs around." Would that suggest using something higher than 87 octane to make up for the lower energy ethanol?
 

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Octane Is Not Energy

As someone mentioned above octane only increases the fuels ability to handle higher compression ratios. If the car is knocking or pinging then, yes, higher octane fuel will improve the performance by doing away with the knock or ping. It wil not however add to the energy content of the fuel. My own experience when I had a car that had pinging in the summer time was that I got lousier milelage out of the higher octane. The way it was explained to me was that the higher octane slowed down the flame front in the combustion chamber so it woundn't pre-combust or ping, but in so doing it slows down the over all rate of combustion and actually somewhat reduces the power of the combustion. Now whether any of that is accurate or not, I am not sure. But my experience was a loss of mileage to prevent pinging.

Your V will do fine on 87 octane. Putting a higher octane will just result in higher fuel costs.



 

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Discussion Starter #9
As someone mentioned above octane only increases the fuels ability to handle higher compression ratios. If the car is knocking or pinging then, yes, higher octane fuel will improve the performance by doing away with the knock or ping. It wil not however add to the energy content of the fuel. My own experience when I had a car that had pinging in the summer time was that I got lousier milelage out of the higher octane. The way it was explained to me was that the higher octane slowed down the flame front in the combustion chamber so it woundn't pre-combust or ping, but in so doing it slows down the over all rate of combustion and actually somewhat reduces the power of the combustion. Now whether any of that is accurate or not, I am not sure. But my experience was a loss of mileage to prevent pinging.

Your V will do fine on 87 octane. Putting a higher octane will just result in higher fuel costs.
Thanks! 87 octane it is.
 

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Although 87 is great, I have heard about how big gas companies like Shell, BP, Amaco, and Exxon have put a detergent/cleaner into their supreme gas, to help keep your engine healthy. ;)
 

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Although 87 is great, I have heard about how big gas companies like Shell, BP, Amaco, and Exxon have put a detergent/cleaner into their supreme gas, to help keep your engine healthy. ;)
Wow. You sound just like a tv commercial. Stick to 87 octane unless you like wasting money.
 

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Top Tier

Although 87 is great, I have heard about how big gas companies like Shell, BP, Amaco, and Exxon have put a detergent/cleaner into their supreme gas, to help keep your engine healthy. ;)
Check out Top Tier gasolines. There are a number of threads on this site and there are other sites devoted to the top tier program. You can use regular gasoline and still benefit from extra level of detergent protection. Search TOP TIER here on the site and Google.



 

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My 98 V seems like it has a rougher idle with the standard 87 octane gas. When i put 89 octane gas it seems to run smoother. The rough idle isn't real bad but it is noticeably smoother when i put the middle grade in it. Maybe i am just weird
 

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My 98 V seems like it has a rougher idle with the standard 87 octane gas. When i put 89 octane gas it seems to run smoother. The rough idle isn't real bad but it is noticeably smoother when i put the middle grade in it. Maybe i am just weird
i see the same results
 

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Octane is not a cure all nor does it contain more energy

The higher octane should have nothing to do with the smoother idle.
What might be going on is that the 89 fuel runs cleaner or some other secondary weird thing is going on. Octane is not a cure all. All fuels today contain detergent particularly when a Top-Tier gasoline.

Now if the higher octane fuel has more detergent, then it might eventually run smother. But that should not be observed right away. If it is then it must be all in your head! It takes time for the detergent to do its thing.

For the last time from WikiPedia:
“The octane rating is a measure of the resistance of gasoline and other fuels to detonation (engine knocking) in spark-ignition internal combustion engines. High-performance engines typically have higher compression ratios and are therefore more prone to detonation, so they require higher octane fuel. A lower-performance engine will not generally perform better with high-octane fuel, since the compression ratio is fixed by the engine design.
The octane number of a fuel is measured in a test engine, and is defined by comparison with the mixture of iso-octane and normal heptane which would have the same anti-knocking capacity as the fuel under test: the percentage, by volume, of iso-octane in that mixture is the octane number of the fuel. For example, gasoline with the same knocking characteristics as a mixture of 90% iso-octane and 10% heptane would have an octane rating of 90.[1] Because some fuels are more knock-resistant than iso-octane, the definition has been extended to allow for octane numbers higher than 100.”


Or in other words, If compression goes up the octane must go up to prevent the pinging as a function of the engine design. But using higher octane than is required by the engine does nothing but waste money! There is not more energy in higher octane fuel! Now if carbon deposits or some other factor are causing pinging, the using a higher octane fuel might restore the timing back to normal. Then the MPG might go up as the octane masks the problem.

octane(ktn)
Any of several hydrocarbons having eight carbon atoms connected by single bonds. It is commonly added to gasoline to prevent knocking from uneven burning of fuel in internal-combustion engines. Octane is the eighth member of the alkane series. Chemical formula: C8H18.

As far as reduced gas mileage goes, if the vehicle has a knock sensor, it will adjust the timing until the pinging is gone or reduced. To do so the timing is retarded and thus the MPG goes down. Lower MPG is due to the Knock detector adjusting the timing. If now a higher octane fuel is added, the knock detector does not need to compensate so the MPG should be back to normal. It makes no sense for the MPG to drop with higher octane unless the knock sensor is still compensating somewhat due to insufficient octane.

The solution is to fix the problem or cause(s) of pinging and use the recommended fuel rather than increase the octane to mask the problem. The added cost of higher octane adds up incredibly fast and is only a Band-Aid!

-Rg
 

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i would read the manual. you will learn at least one thing that will prevent you from screwing up your car in the future, i can pretty much guarantee that ...
 

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Quick Reference Guide

If 350 pages is too much for you to handle, there is also the Quick Reference Guide that is included in the manual package.
My wife loves it because it is very concise.

BTW the OM is very well written!

-Rg
 

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Although 87 is great, I have heard about how big gas companies like Shell, BP, Amaco, and Exxon have put a detergent/cleaner into their supreme gas, to help keep your engine healthy. ;)
It's a marketing scheme. In 2005 IIRC, it was mandated by the Government/EPA that all fuels contain the detergents/cleaners.
 

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It might not be too far fetched to think that some detergent additive packages work better than others. So if Shell claims theirs is better than Texaco at keeping the engine clean, perhaps there might be a slight ever so small truth to the claim. By going beyond the minimum performance of the detergent additive required by law. By and large most of it is marketing hype.

Oil companies are constantly coming up with new additives that are more green or efficient while increasing the bottom line; profits. In the past a lot of the additives have caused a lot of environmental harm.

The raw gas prior to adding the additives is the same for all brands within the same octane range. All the different brand tankers line up and get gas from the same gasoline terminal or depot. This is a fact. So if you think Shell gas is really better than Texaco it is probably all in your head. Your engine does not run any different. All Top Tier gasolines are essentially the same. Any differences in efficiency is due to other external factors! Not the gasoline itself.

Now the percentage of ethanol in the gas does effect the MPG since ethanol does contain less energy as previously stated. If you see a spike one way or the other it might well be due to the percentage of ethanol changes as required in different regions at different times of the year. Your tank from Nevada for instance might have more or less energy (ethanol) than the tank full you got in another bordering state. E10 gas contains more energy than E15 gas. E15 is 15% ethanol and about the highest percentage available for use on vehicles not designed to run on ethanol E85.

Gas without any ethanol contains the most energy and will give you the best MPG.

-Rg
 
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