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You'll be wasting money, that's what will happen :3_puhbye:

91 octane or whatever grade premium gas you get is designed to ignite at higher temperature, and in an engine that only requires a 87 octane regular grade gas, it won't do anything other than hurting performance.
 

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KoreanBoi said:
You'll be wasting money, that's what will happen :3_puhbye:

91 octane or whatever grade premium gas you get is designed to ignite at higher temperature, and in an engine that only requires a 87 octane regular grade gas, it won't do anything other than hurting performance.
Exactly. If you have a severe need to get rid of some money I can be of assistance.

Otherwise, just go with 87.
 

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3 things to consider here.

Premium gasoline usually comes with more additives to keep your injector's and such clean. this may help keep everything running well and keep performance at it's stock max potential.

Also, I've read somewhere... in an article on octane boosters...that higher octane fuel takes more to knock...but once it is ignited it burns faster. this has the effect of advancing the ignition timing on your car. I personally have noticed better gas milage with premium fuel. it is however possibly my imagination as i dont measure these things regularly.

Lastly, with our relitivly high compression ratio, it is unlikely that our ignition timing is advanced as fully as it possibly could be. this means premium fuel could silence the evil knock sensor and help stop the ecu from retarding the ignition timing as it normally would.

All of the above would lead to slightly better perfomance. reguardless a CAI would dominate the gains made by premium fuel and its a one time $150 shot vs an extra 10-15 cents per liter (up here in cananananada) every time you fill up.
 

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JDOGG said:
3 things to consider here.

Premium gasoline usually comes with more additives to keep your injector's and such clean. this may help keep everything running well and keep performance at it's stock max potential.

Also, I've read somewhere... in an article on octane boosters...that higher octane fuel takes more to knock...but once it is ignited it burns faster. this has the effect of advancing the ignition timing on your car. I personally have noticed better gas milage with premium fuel. it is however possibly my imagination as i dont measure these things regularly.

Lastly, with our relitivly high compression ratio, it is unlikely that our ignition timing is advanced as fully as it possibly could be. this means premium fuel could silence the evil knock sensor and help stop the ecu from retarding the ignition timing as it normally would.

All of the above would lead to slightly better perfomance. reguardless a CAI would dominate the gains made by premium fuel and its a one time $150 shot vs an extra 10-15 cents per liter (up here in cananananada) every time you fill up.

Once in a while just to clean the gunks out of the injectors and such is okay, and remember the fact that the ECU takes time to adapt to different fuel grades. Try and keep using 91 octane and your engine will get worse gas mileage after the ECU adapts.

It does take higher temperature for the engine to start knocking with 91 octane fuel, but the fact that it will burn faster at higher temperature also means the air/fuel mixture will detonate before the ECU gives signal to the coils to give spark due to the high cylinder temperatures.
 

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The only difference I noticed between gas was going from the no name gas station from around the corner to a Shell gas station.
 

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It'd be more worth the money to use a name-brand 87 octane than to use anyone's 91, unless the car is FI or nitrous.

I've actually heard overdoing it on the octane over time can leave carbon deposits in the engine. And whenever I have used it (a few times in the Elantra, never have in the Tibby) I have never noticed a difference.
 

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It used to be true that if you put high test in to a car that required 87, you'd damage the motor. Same thing if you put 87 in to a car that requires high test. But the modern car has enough computer sense built in that it wont ping or knock. If you've got a car from like before 1990, chances are you dont have any knock-safety stuff in the computer. Using high test does burn cleaner like somebody said earlier, so in the long run it's better for your engine. And you get slightly better performance.

I run high test all the time in one of my cars, since it's recommended and, after someone put in regular, it pinged like hell. My other car, I mix it up. Sometimes high test, sometimes regular.
 

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Using high test does burn cleaner like somebody said earlier, so in the long run it's better for your engine. And you get slightly better performance.
You will gain zero performance from running higher octane fuel than required in your car. The only reason to user higher octane fuel is if you have a modified engine (higher compression, forced induction, etc). If the car calls for 87, using higher octane fuel only costs you more money. You gan no higher performance.
 

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You will gain zero performance from running higher octane fuel than required in your car. The only reason to user higher octane fuel is if you have a modified engine (higher compression, forced induction, etc). If the car calls for 87, using higher octane fuel only costs you more money. You gan no higher performance.
You dont gain much performance but theyre is a little, theoreticly. The reason high test gasoline has better knock resistance is because it has longer chains of hydrocarbons. once ignited, these longer chains actually burn faster than the shorter chains in low grade gas. Every car on the planet comes with slightly retarded timing from the factory for no other reason than for safety. retarded timing + gasoline that burns faster once ignited = a more fully burnt air fuel mixture at TDC. the fully burnt mixture creates more pressure on the piston, this in turn creates a little more power.
 

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Higher octane fuel is just more reststant to detonation. You don't gain more power from using it unless the engine controls has the ability to increase the timing. Cars that are rated to run on 87 will gain zero performance from using higher octane fuel.

Cars designed to run on premium 91 will see an increase on 91 when compared to regular 87. This is not from the fuel but because the ECM retarded the timing when it was running 87 and advanced the timing on premium. It's the advanced timing that adds the power. The fuel only allows the ECM to do that. On cars that are designed to run on 87, there is not advance added in for fuel above the minium rating.
 

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You will gain zero performance from running higher octane fuel than required in your car.
The statement above is 100% correct... AND a higher octane fuel can, in some cases, assist in leaving less of a carbon build up. However, a tank full every so often is all that is needed. Your tibby is most likely not leaving a huge carbon buildup anyway.. Regular fill ups with 91-93 is a waste.

Not this again NOVA... LOL
 

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Not this again NOVA... LOL
LOL! Maybe Gamz should start a new contest for most annoying NT.com member. I'd probably win that.

As for keeping the engine cleaner I would suggest also adding a bottle of Techron in a tankfull of gas every couple of months as another way to keep the engine and injectors clean. You can get that at most auto parts store. Looks like this:

 

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Nah- It's all good. I just think we beat this horse to death last week.. :3_devil_w
 

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Just put all those pennies you save on buying regular vs premium away, and buy some mods
 

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so our cars are made for lower octanes, could the ecu be remapped or ajusted whatever so the timing could be advanced, bcause i run on pure liquid petroleum gas(real gas) that's injected. car starts on gasoline (super 98) when the car reaches a certain temperature it automaticaly switches to lpg (octane :105-110 ron) and above 5500rpms it shortly swiches back to gasoline. so theoreticaly it can perform better, only if i knew how... without forced induction i mean...:)?
 
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