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Okay, stupid question, I'm. The car is built to run on low grade gas. Will premium/higher octane help or hurt the engine? Please advise, guys!
 

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Just about everyone will say that if Honda says to use regular unleaded (87 octane), using premium is a waste of money. It shouldn't hurt anything though.
 

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Ryouko said:
Okay, stupid question, I'm. The car is built to run on low grade gas. Will premium/higher octane help or hurt the engine? Please advise, guys!

No, they will not help you in any way shape or form. Use 87 octane and be happy your car runs on that, mine does not. There is no need at all to spend the extra money on higher octane. The amount of detergent is the same, the ONLY difference is the octane number.

The octane number is the resistance to combution, in other word how hard it is to burn. 100 octane is defined as pure iso-octane, lower octane refers to the precentage of iso-octane to para-octane, iso-octane is harder to burn, hence the high the iso-octane content, the harder it is burn.

So the only advantage to high octane is better to prevent pre-ignition, which your car does not have a problem with. SO there is no point in purchasing high octane fuel.
 

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palindrome said:
Just about everyone will say that if Honda says to use regular unleaded (87 octane), using premium is a wast of money. It shouldn't hurt anything though.

If used for a long time, it can in fact cause more than normal carbon build up inside the engine. You can start to see this by an increase in the amount of soot (black carbon junk) at the end of your tail pipe.
 

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I burn th 87 for 2 tanks then 1 tank of 93 from Shell because there are some extra cleaners and such which help maintain the fuel system.
 

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Discussion Starter #6
Wow, thanks for the input guys, I really appreciate it.

My initial reaction, coming from a car that was required to run premium, was that, if you put lower grade octane into a car that required premium, it would damage the engine. So, using the same logic (or maybe its not the same, now that I think about it!) using higher grade gas in a car that didn't need it would be beneficial.

^Yeah, now that I think about it, I DID contridict myself... Guess I'll switch back to 87 octane.
 

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Texan06 said:
I burn th 87 for 2 tanks then 1 tank of 93 from Shell because there are some extra cleaners and such which help maintain the fuel system.

Federal law in the US prevents a station or company to put different amounts of cleaners in fuels that are dispensed via the same nozzle.

What this means is that if the gas station has only one nozzle to dispense all the grades of gas, they all MUST have the same cleaners in them regardless of grade. Only if the station has different nozzels for EVERY grade of gas, can they have different amount of cleaners/detergents in the different grades of gas. If you believe Shell has better cleaners in their 93 octane, their 87 has the same because of Federal law.
 

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interesting thread. It's reverse if you have a premium-requiring tank. Running 87 or lower than premium will, overtime, increase build-up and all that nasty crap in the engine. Initially, it will slightly lower your mileage per tank and um...something else, but I'm having a brain fart. I would think running premium would actually help a non-premium car, in terms of gas mileage, etc?
 

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Using an octane that is too low can cause pre-ignition (knocking/pinging). This means the combustion is occurring too soon in the compression cycle. That is, the piston is on its way up in the cylinder when combustion (prematurely) occurs. Obviously this is not good for the engine. This is usually caused when using a low octane gas in a high-compression engine.

Some engines have knock sensors that actually detect pre-ignition knock and adjust the engine timing to reduce or eliminate it. This usually results in reduced engine performance.

I think most everyone agrees that using a higher octane than is required does NOT give you better MPG. You're just wasting money on gas that is more expensive than you need.

Bottom line: Use the octane rating that is recommended by the car manufacturer. (Unless of course you have modified the engine).
 

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this is awsome, cuase ive been paying out the ass for gas my car requires 93 oct. no less... so looks like the civic is gunna save my wallet
 

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palindrome said:
Using an octane that is too low can cause pre-ignition (knocking/pinging). This means the combustion is occurring too soon in the compression cycle. That is, the piston is on its way up in the cylinder when combustion (prematurely) occurs. Obviously this is not good for the engine. This is usually caused when using a low octane gas in a high-compression engine.

Some engines have knock sensors that actually detect pre-ignition knock and adjust the engine timing to reduce or eliminate it. This usually results in reduced engine performance.

I think most everyone agrees that using a higher octane than is required does NOT give you better MPG. You're just wasting money on gas that is more expensive than you need.

Bottom line: Use the octane rating that is recommended by the car manufacturer. (Unless of course you have modified the engine).
Interesting. But unfortunately I'm going from a Legend to an Si...won't make a difference on my wallet like some of you guys. :(
 

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Texan06 said:
I burn th 87 for 2 tanks then 1 tank of 93 from Shell because there are some extra cleaners and such which help maintain the fuel system.

if u wanna clean it then use FP60 from lubecontol.com. This stuff works way better than Shell Vpower and can improve mpg. Mine went up 2mpg
 

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skittleslegend said:
interesting thread. It's reverse if you have a premium-requiring tank. Running 87 or lower than premium will, overtime, increase build-up and all that nasty crap in the engine. Initially, it will slightly lower your mileage per tank and um...something else, but I'm having a brain fart. I would think running premium would actually help a non-premium car, in terms of gas mileage, etc?

Well, I never expected anything to happen, but when I had my '03 civic, I decided to try 93 in it for a couple of tank. I got the worst MPG with that, my milage actually went to around 27-28 MPG where it was around 30-31. I never figured out why it went down, but I know it did. Others have also noticed the same thing, I can't explain it. The car did seem to have more pick up for the first tank, but then it starting getting more and more sluggish, and after 3 tanks of 93 octane, I went back to 87 it was revivied again. Ever after that, I just use whatever they say to use.

Yeah, you don't want to use lower octane in a high octane eninge. My GS-R requires 91 octane, the guy before me used 87 all the time I think, I've had to take the ehads off and clean them because of HUGE amounts of carbon build up. Basically it is dependant on the ignition timing and compression ratio as to what grade of gas you use.
 

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wickett said:
this is awsome, cuase ive been paying out the ass for gas my car requires 93 oct. no less... so looks like the civic is gunna save my wallet

Should be able to take 91 octane, since in California that is the highest octane they have so the car should be made to use 91 :)

I know around me it is hard to find 91 because everybody sells 87,89, and 93 and that's it. I have my favorite station now that sells 87,89,91,93 and 95 octane so I always just get the 91.
 

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There is an article I think at TOV that says the Civic doesn't need anything higher than 87, however the car sometimes knocks at a low idle so a higher octane may help with that. They also mentioned about buying cheaper gas versus brand name gas and the detergents in gasoline. I'm not going to explain the whole thing here but it's a good article to read if your going to run your car to 200,000 miles.
 

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civicdude06 said:
There is an article I think at TOV that says the Civic doesn't need anything higher than 87, however the car sometimes knocks at a low idle so a higher octane may help with that. They also mentioned about buying cheaper gas versus brand name gas and the detergents in gasoline. I'm not going to explain the whole thing here but it's a good article to read if your going to run your car to 200,000 miles.

Link to the article?

I plan to run my car until the wheels fall off and the engine falls out.
 

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Jrfish007 said:
Federal law in the US prevents a station or company to put different amounts of cleaners in fuels that are dispensed via the same nozzle.

What this means is that if the gas station has only one nozzle to dispense all the grades of gas, they all MUST have the same cleaners in them regardless of grade. Only if the station has different nozzels for EVERY grade of gas, can they have different amount of cleaners/detergents in the different grades of gas. If you believe Shell has better cleaners in their 93 octane, their 87 has the same because of Federal law.
hmmm..interesting, than i guess the cleaners of the premium gas of shell must have a little "kick to it" because when i use the the higher octane from shell, and shell only, i feel a greater kick to my car....jus my experience...
 

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Is it only the V-Power grade of Shell that has these extra detergents? Or is it all grades?

I did notice that the TopTier site mentions all grades must meet the higher standards. In which case, what's up with V-Power? Just a higher octane?
 

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wlfkaw said:
Is it only the V-Power grade of Shell that has these extra detergents? Or is it all grades?

I did notice that the TopTier site mentions all grades must meet the higher standards. In which case, what's up with V-Power? Just a higher octane?

yes they all have to have the same detergents.

The V-power thing has two things: 1. marketing, stupid people may equate V-power to VTEC, and it works. 2. it is a higher octane, the difference is that they use a little more methanol to help achieve the higher octane instead of adding iso-octane.
 
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