[Villian]

I have a rsx-s and i been putting in regular gas since its cheaper the premium gas

and it said to put in premium

does it matter much? will it hurt my engine?

[erure]

Not to introduce a radical concept, but have you tried reading your owner's manual? If it says to use premium, my advice is to use premium. If it says regular, use regular. The fact that your note indicates no acquaintance with such matters suggests that you may in fact be a scam victim, assuming by this you mean "someone who believes what he hears in commercials." I have a hard time working up much outrage over this deception, since discovering the facts requires so little effort. If you don't mind paying the extra money for no reason, don't expect the oil companies to suffer any pangs accepting it.

In most of the U.S., regular gas has an octane rating of 87, midgrade gas is 89, and premium is 91 or 92. (Octane ratings are lower in the mountain west due to the effects of thin air on internal combustion.) Contrary to widespread belief, the octane rating doesn't indicate how much power the fuel delivers; all grades of gasoline contain roughly the same amount of heat energy. Rather, a higher octane rating means the fuel is less likely to cause your engine to knock or ping. Knock, also known as detonation, occurs when part of the fuel-air mixture in one or more of your car's cylinders ignites spontaneously due to compression, independent of the combustion initiated by the spark plug. (The ideal gas law tells us that a gas heats up when compressed.) Instead of a controlled burn, you get what amounts to an explosion--not a good thing for your engine. To avoid this, high-octane gas is formulated to burn slower than regular, making it less likely to ignite without benefit of spark.

The majority of cars are designed to run on regular gas, and that's what the manuals tell the owners to use. Higher-performance cars often require midgrade or premium gas because their engines are designed for higher compression (higher compression = more power), and regular gas may cause knock. If your car needs high-octane gas, the manual will say so.

Using high-octane gas in a car designed for regular accomplishes little except more rapid combustion of your money. Some refuse to believe this, claiming, for example, that premium gives the family Toyota better mileage or more power. These people are in dreamland. Others say premium is purer or contains detergents that will cleanse your engine of uncouth deposits. Likewise misguided thinking--government regulations require detergents in all grades of gasoline. (BP Amoco, I notice, asserts that its premium gasoline contains more detergents than legally required; if you think that's worth 20 extra cents a gallon, be my guest.) Some automotive types claim that using premium in a car designed for regular will make the engine dirtier--something about deposits on the back side of the intake valves. I've also heard that slower-burning high-octane gas produces less power when used in ordinary cars. Believe what you like; the point is, don't assume "premium" means "better."

Occasionally you get some genius who takes the opposite tack--he spends an extra 10 or 20 grand buying a high-performance car, then decides he's going to save three bucks per tankful using regular instead of premium as specified. He figures as long as the engine doesn't knock he's OK. Wrong, carbon monoxide brain. Car engines nowadays contain knock sensors that detect detonation and automatically retard the spark to compensate. The delay means maximum gas expansion occurs when the piston is farther along in its downstroke and thus there's more room in the cylinder head. This reduces peak cylinder pressure, eliminating knock but also giving you less power and poorer mileage.

You may ask: Don't knock sensors make it hard to tell when an old car needs higher-octane gas? Years ago, when your beater started pinging on grades or under acceleration, that was the sign that carbon had built up in the cylinders, increasing compression, and it was time to switch to high-test. Now the knock sensors compensate, which seemingly might conceal the problem. Don't fret--today's fuel injection systems precisely meter the fuel-air mix, resulting in fewer unburned hydrocarbons and less carbon buildup. If you're still concerned, I'd say it makes more sense to spend $6 on a bottle of carbon clean-out juice than an extra $150 a year on high-priced gas.

I got that from http://www.straightdope.com/columns/041008.html

[wtfrankk]

someone correct me if im wrong regular gas may be a bit more grittier compared to higher octane?

but what i do know for sure is that when you take a car to get dynoed in order to get the highest results possibile, high octane fuel was used. so from that im guessing higher octane would ignite bigger sparks in the combustion chambers thus puts out more power.

im running a b16 engine which is dohc vtec and somewhere in the books they say u need premium for vtec engines. but ive never pumped premium ever in my life and its ran just fine, and pulled just as hard. i always pump the middle one =]

the rsx-s should be the the k20 ibelieve. id say just pump the middle one too. just because pumping regular feels so cheap for such a good engine and premium just hurts unless ur a baller then no problem!

[phantompc4]

If i were u i wouldnt put lower octance fuel in your car. but then again u are driving a honda so its probably okay. from what i know most expensive cars have recommended premium gas. it just keeps the engine healthier and longer lasting.

[jphase]

read the sticker on the window.. many people put premium in their car when its only RECOMMENDED. If its recommended you do not need to put premium. If it says REQUIRED then you need to put premium.

[phantompc4]

thats not true. my car it says premium gas recommended but if you put in anything lower itll choke the car and u better have another 4Gs for the new engine then.

[jphase]

really? cuz thats what's been on the news lately and car manufacturers back that up too or says the news report from cnn, yahoo, fox, etc.

[azn akira]

thats not true. my car it says premium gas recommended but if you put in anything lower itll choke the car and u better have another 4Gs for the new engine then.

not true, it will run ok on lower octane. though i would only use 91

to the OP how cheap are you? the difference is like .10 a gallon...you only pay a couple extra bucks. higher octane protects against knocking because its more resistent to combustion. use the higher octane your engine will run more efficiently because it an advance the timing. you may infact be getting worse mpg 89

[TyneeTom]

your engine is tuned/designed for a specific octane. compression ratio also taken into consideration.


Use what is recommended.

k thx, bye.


or get it re tuned to be efficient with regular.............which is unheard of i think. =_=

[wtfrankk]

^ aznakira sorry youre wrong.

engines with higher compression ratio need higher octane fuel. i dont really know too much about compression ratio its a bit technical, but in simple form..

it should go something like
higher compression ratio=bigger combustion chamber=more available oxygen=more power

*edit* aw tyneetom i was gonna mention compression but u beat me to it lol

[azn akira]

^ aznakira sorry youre wrong.

no im not. he's saying his car (rx8) cant run on anything below 91 octane. guess what? it can, people do it all the time.

http://www.rx8club.com/showthread.php?t=85...light=89+octane

and idk how you can even argue the 2nd part of my post. octane is a measure of volatility, higher octane is more resistant to combustion. allowing the OP's car to run more advanced timing (since its supposed to have 91 octane) than running 89 octane.

next time you try and correct me you better bring your A game

[TyneeTom]

You're both right =_=.....there

[hungrycollegeboy]

The difference is 20-30 cents.

[wtfrankk]

aznakira please i was going more by the books, and no durrh cars can run on lower octane, only hardcore enthusiasts would keep it premium. just know damage to engine is damage to engine, no matter how little it may be considered to the human eye. things like recommended octane are tested and proven by engineers that actually study this stuff, and spend their entire career working on cars.

btw if u read my first post ud know i already stated that i dont pump the recommended octane even on my own car.

AND LOL i never even questioned ur 2nd part to what is octane, so stop trying to off to get at me.
acting so smart and cool, throwing around fancy words like ur somebody special.

[anothermixedfob]

i think its the Octane! more octane the better for your engine. I remeber my driving instructor telling me that the more octane the fuel has the more efficient the engine runs or something like that

[azn akira]

ok so why did you say i was wrong? because you agree with both of my statements....

only hardcore enthusiasts would keep it premium

ummm no. people who aren't cheap keep it premium. you only save a couple bucks

just know damage to engine is damage to engine, no matter how little it may be considered to the human eye

running lower octane doesnt necessarily damage your engine. you just run the increased risk of pre ignition. your ecu will adjust for the decrease in octane and retard the timing, no engine damage will occur under normal operating conditions you just loose efficiency

acting so smart and cool, throwing around fancy words like ur somebody special.

fancy words? what fancy words? i didnt use any fancy words. if you think those words are fancy you need to go back to your 9th grade english class

[aznfishyfart]

wats considered high compression ratio?

also if it recomends high octane....u dont need it, but u will lose some horses
my mom's v6 highlander recommended 91 but we always used 87....never had a problem with the engine after 4 years
the ecu is supposed to compensate for that and retarded the timing so yea....

[wtfrankk]

ok so why did you say i was wrong? because you agree with both of my statements....

lol nope i only disagreed on ur first statement telling u theres more behind the recommendation.

ummm no. people who aren't cheap keep it premium. you only save a couple bucks

entirely subjective cheap to you aint cheap to others mr big baller

running lower octane doesnt necessarily damage your engine. you just run the increased risk of pre ignition. your ecu will adjust for the decrease in octane and retard the timing, no engine damage will occur under normal operating conditions you just loose efficiency

+1 problems in the far future imo

fancy words? what fancy words? i didnt use any fancy words. if you think those words are fancy you need to go back to your 9th grade english class

i pass my english classes with Cs and Ds, brotthhaaa I DONT GIVE A JOHN TESH OK? <-- lols i know

[jihyepii]

uhm I'm not quite sure if it'll hurt your engine but I had to pay $70 to drain my gas tank cuz I accidently put Premium Plus or was it (Diesel) and my 1994 Honda only took Unleaded.

[heyitzthatfc]

lock this thread imo.

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