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If your manual calls for regular, use regular. (unless your civic has a turbo)

 
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informative....yet, to the point...

 
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thank you captain obivious
























haha...........j/p

 
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It's hard to get people to not think that higher octane equals better equality

 
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Exactly what I was thinking lmfao

 
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while it may be true, there are benefits to use using higher octane such as better detergents etc.

read this too

http://www.hypemakers.net/toptier/go.php?v=f&adv=2228

 
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now lets wait and see how many "what octane?" threads we will get.........

 
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If you want better detergents use FP60 www.lubecontrol.com with regular.

 
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ya there is a reason why they have it in the manual to use 86 even tho its 87. Its not as common in our cars. But if you are suppose to use 87 and u use 93 all the time it will burn out your injectors (like POS chrylsers/dodge and well mostly all american made cars).

But of course with turbo cars u use higher octane but then u usally have better injectors that can handle it. There are other reasons but this is one of the biggest reasons of why u dont use high octane gas with cars that arent meant to be use it.

 
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I still don't understand how higher octane messes up injectors. Doesn't the gas just flow through it?

 
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Im not exactly sure but man i have a dumb *** father in law that thought the same as most the people on here and thought cause it was 93 it has to be good for his car. And he burnt out 4 sets of injectors within like 6 months of owning his POS PT cruiser. Dealer didnt realize what was going on until the last time he was having problems i asked what kind of gas he was using and he brought that up to the dealer and they told him that was why they also made him pay for the 4th set. Ever since he has used 87 and hasnt had a problem.

It was something my dad always told me to. It just something that kinda stuck and well ive heard it quiet a few times from different people it happen to.

 
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i dont get how it would burn up injectors. its cleaner so it should flow better. what exactly do you mean by "burn up"

 
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i said im not sure...but im gonna go search about it. Ive had several people tell me this. and like i said the chrylser dealer also told my father in law the same thing couple months ago. Im just repeating what i heard....if i find something ill post it up.

 
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cool. i aint attackin ya just wondering because ive never heard of it and its definately something to know. (even tho im too cheap to get the premium anyways cus it really doenst have positive effects i would notice)

 
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I think it mainly depends on the type of injectors in the cars that why i said its not to common in our cars. But more in american cars like chrylsers. And my dad told me this years ago and he worked as a mechanic for dodge for 10 years then became a engineer. But ill look tomorrow its 1 in the morning and my kids will be up in like 5 hours. so ill see if i find any info about this tomorrow.

 
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lol sounds good. im gonna hit the sack also

 
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there are different addatives in gas that can damage the injectors over a long period of time, if your injectors were not made to withstand premium.

this is a long shot, though. your main concern is the fact that your car will not be able to detonate the mixture thoroughly and completely since you cannot maintain a high enough compression and/or heat to do so.

though there are a few more detergents/cleaning agents in higher octane gas, buying a bottle of chevron techron fuel addative and putting it into a tank of regular gas will be far better and accomplish much more than buying a tank of premium. (in fact, chevron actually puts a small amount of chevron techron in their premium gas)

 
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What about getting 89 instead of 87? It's not much difference just 2 octanes higher. I'm guessing because I don't know about octane, but my compression is for sure higher than stock.

 
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My opinion on this, everyones right. Just because you put more octane doesn't mean your going to go better. If you put 150 octane in your civic your not gonna break 10's. But on the other hand turbo cars the more octane the better they run, but again like everyone said you got to worry about your injectors going bad. I've also heard this but I don't know if its true. Some people say once in awhile like if you always use 87, once in awhile put 9* to clean out something? Not sure exactly what probably they are talking about injectors but I'm a little lost on that...any opinions?

 
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Well premium 93 or whatever it is usually has more detergents like s2000man01 said, but you can just go buy some lucas fuel cleaner and throw that in with the lower grades. And with the new top tier program, the lower octanes should have acceptable amounts of detergent as well. So don't run higher unless your engine needs it. I think Si/rsx needs 89 because of higher compression. I still don't know how more octane damages injectors from spraying it.

 
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I'm looking into the injector thing. though there probably is not much relevance to that now that I understand the issue.

the reason turbo cars run better with higher octane is because they are essentially having a higher compression ratio in their combustion chamber from boost. with lower octane gas, they may detonate and lose power. higher octane gas helps prevent this.

but again, if you put higher octane gas in when not needed, you may not be able to detonate the mixture completely and thoroughly. this will cause a loss of power as well as more buildup and crap coming out of your exhaust gasses.

 
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yes

 
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ya i havent had much time to do any actual research about it. but i havent came up with nothing as of yet. The weekends are usally busy for me. I can usally do more research at work since I dont do nothing until a computer is broke.

 
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i noticed power loss when I put in 93 a couple tanks. Went back to 89 and it feels better.

 
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Correct me if I'm wrong but I thought my manual said a "minimum of 87 octane or higher". I'll ask my wife to verify next time I talk to her. I've been running 93. I want to run 100 at the track when I get N20. Maybe I'm just wasting money, but until I get some concluseive expert opinion I'll stick to what works for me.

 
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I'm not sure what kind of expert opinion you are looking for. But if you are running 93 octane, you ARE losing power, and you ARE going to build up crap and contaminants in your engine much quicker. They always say 87 or higher, because of the fact that some places may only offer 88 or 89.

You are wasting money, you are losing power, and you are gonna have a fairly gunked up engine by the time you get up there in mileage.

I'll explain this again since you seemed to have missed the technical explinations. The only thing octane rating is, is resistance to detonation and heat. The higher the octane, the more heat required to get the mixture to ignite.

Hence the reason cars with higher compression engine or turbos require premium. Cars with turbos, etc, and with higher compression tend to have their mixture get much hotter in the combustion chamber before the ignition spark. Using a lower octane gas in a car that requires premium causes premature detonation (which is bad, duh) since the heat detonates the lower octane gas.

Likewise, if you are using higher octane gas in your civic, the mixture may not get hot enough in your combustion chamber to burn completely through. This leaves excess fuel/air mixture in your combustion chamber during the exhaust stroke, causing a loss of power and buildup of excess contaminants. Stop using 93 octane, because you're losing power and you're pissing money away. This also burns your valves and over time you will burn through them.

As for using high octane gas and nitrous, this is somewhat a paradoxical situation. Nitrous can benefit from using higher octane gas, since the oxidization process induced by nitrous causes the mixture to super heat. again higher octane gas is more resistant to heat, therefore will help prevent detonation when spraying.

however, when you're not spraying, you're back into the category above, where it's causing loss of power and excess waste and contaminants.

As for using 100 octane gas in your car, I'd advise against that in a very cautious sense. The addatives in higher octane gas worsens the effect you're seeing here, even if you're using nitrous. Turbos can use it if they crank up their boost to the point that they'd benefit from it. However, most don't do that unless they've been tuned for it, becuase running high octane gas and high boost without being tuned is a very dangerous combination to gamble with.

If you see some ricer in his n/a civic filling up with 100 octane, point and laugh, because everyone else who actually knows what they are doing, will certainly be laughing along with you.


Oh and I found out the thing with the injectors. The addative that they use to give gas its higher octane can cause premature injector failure, injector misfires, etc, if your injectors were not made for that kind of fuel. This is an extreme case and few and far between, but it can happen, and does happen. I have to go back and look, but the addatives cause buildup on the injectors, leading to the above said failures. However, this is not always the case, so really, it's hardly worth mentioning.

 
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i did a small expierment with 76's 87 gasoline and 89.

results: 89 gave me 40 to 50+ more miles off a complete tank compared to 87. my driving habits were spirited and moderate, never redlined, only hit 6k at most (of course to merge on the highway lol). mods were intake/no cat
climate was in cali weather (it wasnt heated, but sunny and at times, chilly/sprinkles). city driving mostly and 1/6 of the time seen the highway on both tanks.


from now on, im gonna switch over from 87 to 89 rapidly. IE: 87 this time, 89 next, then 87 again, so on.


ill prob expierment 91 some other time

 
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Doesn't higher octane fuels simply burn more completly? Look at methanol for example.

I dunno.

Someone needs to post a study; this is all hear-say.

 
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higher octane burns more completely yes. it burns cleaner also.

 
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Dear god this is not hearsay. This is SCIENTIFIC FACT! Methanol is completely different than using pump gas. You can't even compare the two.

No, higher octane gas does not burn more cleaner, nor does it burn more completely.

AGAIN. for the last time.

ALL THE OCTANE RATING MEANS IS THAT IT IS MORE RESISTANT TO DETONATION AND HEAT!!!


And as for the person who got better mileage with 89 than 87. Assuming your car isn't FI'd then you did NOT get better mileage just because you used higher octane. There are too many other factors involved to do an experiment like that. The ONLY case where this would be is if your car was detonating for some reason, but you'd get a CEL if something was that majorly wrong.

Also, the whole "well premium gas has more cleaners in it to help your car". wrong. government regulations prevent this. the only difference is the addative used to increase octane rating.

Once again. Higher octane gas is more resistant to heat and detonation. (this also means it takes longer to burn, which is WHY if you DONT have a car set up for premium you'll eventually burn through your valves). If you are going to run premium you have to tune for premium. you would have to advance your timing 2 degrees and retard your exhaust valves in order to allow the mixture to burn through completely before the scavaging of the chamber.