regular vs. premium gasoline?

[Wheatmaster]

is there any real difference? premium costs much more in the long run and i want to know is there a real advantage to premium gasoline? cleaner? smoother ride? faster acceleration?

 

[Pepsi90919]

higher resistance to detonation.

check your owner's manual and use that.

 

[Fiveohhh]

only need premium if your motor requires it, otherwise there is very minimal gain in power over 87

 

[boyRacer]

Originally posted by: Pepsi90919
higher resistance to detonation.

check your owner's manual and use that.

 

[Slickone]

No advantage, not cleaner, not smoother, not faster (unless your engine needs/can use it). As mentioned, go by your owners manual. It's actually less clean, since it has additives to make it burn slower. Using higher octane when you don't need it can actually do more harm than good by leaving deposits since if your engine doesn't need/can't use it, it isn't fully burned.

 

[Kalvin00]

Yep, what everyone else said before me.

 

[OREOSpeedwagon]

I go with 87 but I've noticed my car starts up a lot quicker if I use 93.

 

[Cashmoney995]

It's all about the octane rating.
If you have deep pockets its ok to get a car that uses it. If not, its not the greatest thing to get.

One reason not to buy the Toyota Camry is because the V-6 Model requires Premium gas. What a rip.

 

[Zenmervolt]

Originally posted by: Slickone
No advantage, not cleaner, not smoother, not faster (unless your engine needs/can use it). As mentioned, go by your owners manual. It's actually less clean, since it has additives to make it burn slower. Using higher octane when you don't need it can actually do more harm than good by leaving deposits since if your engine doesn't need/can't use it, it isn't fully burned.

Wrong. Using higher octane than required will do not harm to your engine. It will harm your wallet, but not your engine. The only thing that octane does is raise the self-ignition point. A spark plug in any engine operating with a stoichiometric fuel/air mixture (i.e. any modern engine) will ignite the fuel/air mixture for a full burn regardless of the octane level of the fuel and regardless of the engine's octane requirements. Octane prevents self-ignition from compression before the spark plug fires, which is a concern in high-compression engines.

Whoever gave you that "information" about higher octane fuel being less clean should not be allowed to touch a car.

ZV

 

[Luhny]

funny question because i was reading cnn.com and they also said to uses 87 octane unless manual says too but actually newer cars are more fuel efficent and need less octane

 

[Wheatmaster]

Originally posted by: Zenmervolt

Originally posted by: Slickone
No advantage, not cleaner, not smoother, not faster (unless your engine needs/can use it). As mentioned, go by your owners manual. It's actually less clean, since it has additives to make it burn slower. Using higher octane when you don't need it can actually do more harm than good by leaving deposits since if your engine doesn't need/can't use it, it isn't fully burned.

Wrong. Using higher octane than required will do not harm to your engine. It will harm your wallet, but not your engine. The only thing that octane does is raise the self-ignition point. A spark plug in any engine operating with a stoichiometric fuel/air mixture (i.e. any modern engine) will ignite the fuel/air mixture for a full burn regardless of the octane level of the fuel and regardless of the engine's octane requirements. Octane prevents self-ignition from compression before the spark plug fires, which is a concern in high-compression engines.

Whoever gave you that "information" about higher octane fuel being less clean should not be allowed to touch a car.

ZV

ok this sounds like what my dad's mechanic told me about. looks like more investing in premium.

 

[StageLeft]

Originally posted by: Fiveohhh
only need premium if your motor requires it, otherwise there is very minimal gain in power over 87

Car and drive (?) did a test and a big pickup gained about 2 mp, and an accord lost it. Basically there is no good reason to use premium if your motor doesn't use the compression that benefits from premium.

funny question because i was reading cnn.com and they also said to uses 87 octane unless manual says too but actually newer cars are more fuel efficent and need less octane

I was under the impression that in the arms race for horsepower a lot more cars require high octane. IIRC the wrx sti (unusual, I know) requires for optimal performance a 95 pump octane, which is impossible to get in most places!

 

[Slickone]

Originally posted by: Zenmervolt

Originally posted by: Slickone
No advantage, not cleaner, not smoother, not faster (unless your engine needs/can use it). As mentioned, go by your owners manual. It's actually less clean, since it has additives to make it burn slower. Using higher octane when you don't need it can actually do more harm than good by leaving deposits since if your engine doesn't need/can't use it, it isn't fully burned.

Wrong. Using higher octane than required will do not harm to your engine. It will harm your wallet, but not your engine. The only thing that octane does is raise the self-ignition point. A spark plug in any engine operating with a stoichiometric fuel/air mixture (i.e. any modern engine) will ignite the fuel/air mixture for a full burn regardless of the octane level of the fuel and regardless of the engine's octane requirements. Octane prevents self-ignition from compression before the spark plug fires, which is a concern in high-compression engines.

Whoever gave you that "information" about higher octane fuel being less clean should not be allowed to touch a car.

ZV

Funny, that's the first time I've heard anyone disagree. I've read all over the place and seen it explained that way quite a bit. I've hung out on auto forums for years too. But I don't have time right now to even argue, much less get refs, etc. BTW, I didn't say it'd 'harm your engine' per se.

 

[Zenmervolt]

Originally posted by: Luhny
funny question because i was reading cnn.com and they also said to uses 87 octane unless manual says too but actually newer cars are more fuel efficent and need less octane

Great, CNN is spreading mis-information now. No, the more efficient the engine, the more octane it will require. Higher compression ratios produce more power but need higher octane fuel. The reason that most "economy" cars use regular gasoline is simply cost. It costs more to make a high-compression engine (higher stresses, more complex ECU programming, better fuel delivery componants, etc) and the fuel costs more. Plus, the gains are small. It's far easier to take a low-tech, relatively inefficient (in terms of hp per unit of fuel used) engine in a small, light car and get high mileage that way. Also, the people who can't afford more expensive cars don't want to pay for premium fuel. They aren't going to care about that extra one mile per gallon if it means they need premium fuel to get it.

ZV

 

[Zenmervolt]

Originally posted by: Slickone

Originally posted by: Zenmervolt

Originally posted by: Slickone
No advantage, not cleaner, not smoother, not faster (unless your engine needs/can use it). As mentioned, go by your owners manual. It's actually less clean, since it has additives to make it burn slower. Using higher octane when you don't need it can actually do more harm than good by leaving deposits since if your engine doesn't need/can't use it, it isn't fully burned.

Wrong. Using higher octane than required will do not harm to your engine. It will harm your wallet, but not your engine. The only thing that octane does is raise the self-ignition point. A spark plug in any engine operating with a stoichiometric fuel/air mixture (i.e. any modern engine) will ignite the fuel/air mixture for a full burn regardless of the octane level of the fuel and regardless of the engine's octane requirements. Octane prevents self-ignition from compression before the spark plug fires, which is a concern in high-compression engines.

Whoever gave you that "information" about higher octane fuel being less clean should not be allowed to touch a car.

ZV

Funny, that's the first time I've heard anyone disagree. I've read all over the place and seen it explained that way quite a bit. I've hung out on auto forums for years too. But I don't have time right now to even argue, much less get refs, etc. BTW, I didn't say it'd 'harm your engine' per se.

Explain to me how "Using higher octane when you don't need it can actually do more harm than good by leaving deposits" is not saying that it will harm your engine. I'd love to see how you get out of that.

And I hate to tell you this, but I've hung out on automotive forums for years as well. They are some of the worst places to get automotive advice unless you know what you're talking about before you go there. The typical automotive forum has perhaps 5 members who know what they're doing and the rest just spread BS theories. Incomplete burn always indicates a fault in the engine, generally fuel delivery (too rich, non-stoichiometric fuel ratio, often from poorly done modifications to the ECU) or spark (dirty/old plugs, weak coil or worn out plug wires). You can run premium fuel in a lawn-mower and it won't leave deposits. I say again, your "information" is bullsh!t unless you're trying to use jet fuel or something.

ZV

 

[GalvanizedYankee]

In todays world of street engines premium is generally required for large bore (+95mm) motors with low combustion chamber turbulence and the spark plug located to the side of the chamber. This is a recipe for detonation
because of the slow burn, temps/pressures rise at such a rate the remaining charge explodes when it should just burn.
Nissan and many others did dual plugged their heads as a work around. It's an OK solution but still a compromise.
Dual plugs means one is on opposite sides of the same chamber. Many of us that run old air cooled motors are forced into having the heads fitted for dual plugs.

A well designed, highly turbulent chamber with a centrally located plug can run compression ratios of 12 to 1 on 87 octane. Many motorcycles do. One of the real advantages of a 4 valve head is it's spark plug location and turbulence.
The turbulence I'm referring to happens just before ignition as a result of the piston coming up to the squish band of the cylinder head. Plus smaller engines usually have smaller bores.

The bottom line is run what the manufacture specs.

 

[RobCur]

The reason for 3 different type of gasoline? there 3 different types of engine.
4 cyclinder, small engine need highest quality like supreme/premium
6 cyclinder, unleaded plus
8 cyclinder, regular unleaded
Very simple.

 

[Howard]

Originally posted by: galvanizedyankee
In todays world of street engines premium is generally required for large bore (+95mm) motors with low combustion chamber turbulence and the spark plug located to the side of the chamber. This is a recipe for detonation
because of the slow burn, temps/pressures rise at such a rate the remaining charge explodes when it should just burn.
Nissan and many others did dual plugged their heads as a work around. It's an OK solution but still a compromise.
Dual plugs means one is on opposite sides of the same chamber. Many of us that run old air cooled motors are forced into having the heads fitted for dual plugs.

A well designed, highly turbulent chamber with a centrally located plug can run compression ratios of 12 to 1 on 87 octane. Many motorcycles do. One of the real advantages of a 4 valve head is it's spark plug location and turbulence.
The turbulence I'm referring to happens just before ignition as a result of the piston coming up to the squish band of the cylinder head. Plus smaller engines usually have smaller bores.

The bottom line is run what the manufacture specs.

Swirl > turbulence :beer:

 

[Heisenberg]

Originally posted by: RobCur
The reason for 3 different type of gasoline? there 3 different types of engine.
4 cyclinder, small engine need highest quality like supreme/premium
6 cyclinder, unleaded plus
8 cyclinder, regular unleaded
Very simple.

Err...no.

 

[Nebor]

Originally posted by: RobCur
The reason for 3 different type of gasoline? there 3 different types of engine.
4 cyclinder, small engine need highest quality like supreme/premium
6 cyclinder, unleaded plus
8 cyclinder, regular unleaded
Very simple.

Man, so following that progression, I guess you just piss in the gas tank for a v12 ferrari?

 

[fyleow]

Originally posted by: RobCur
The reason for 3 different type of gasoline? there 3 different types of engine.
4 cyclinder, small engine need highest quality like supreme/premium
6 cyclinder, unleaded plus
8 cyclinder, regular unleaded
Very simple.

WTF

 

[Eli]

Originally posted by: RobCur
The reason for 3 different type of gasoline? there 3 different types of engine.
4 cyclinder, small engine need highest quality like supreme/premium
6 cyclinder, unleaded plus
8 cyclinder, regular unleaded
Very simple.

Do not listen to this person, he has absolutely no idea what he is talking about.

Listen to ZV. Although I will admit I have heard the carbon thing a lot too. It is definately plausible, because even if only a few molecules fail to burn completely, it will contribute to carbon deposits. But he is probably right, in an engine that is operating at 100%, it isn't going to make any difference except in your wallet.

I'm going to go as far as to partially disagree, I think. I know that carbon deposits can be an issue, even when you are using the proper octane, if the engine sees prolonged periods of idling and realitivly low RPMs. Since it is difficult to achieve 100% burn in such conditions, anything that makes the gasoline harder to burn would theoretically contribute to the problem. But again, I agree that in an engine that is operating properly, it won't be as much of an issue. But engines only operate 100% within specs for a few tens of thousands of miles. After that, it's slowly downhill as wear progresses, compression goes down and leakdown goes up...

I would also like to add that higher octane gasoline does not produce more power, it produdes less. Remember, energy doesen't just appear, it just changes forms. The higher the octane, the less energy the fuel contains. Even though the difference is going to be measured in tenths of a mile per gallon(if that), it's still just a waste if your engine doesen't require it.

 

[fyleow]

Originally posted by: Eli

Originally posted by: RobCur
The reason for 3 different type of gasoline? there 3 different types of engine.
4 cyclinder, small engine need highest quality like supreme/premium
6 cyclinder, unleaded plus
8 cyclinder, regular unleaded
Very simple.

Do not listen to this person, he has absolutely no idea what he is talking about.

Listen to ZV. Although I will admit I have heard the carbon thing a lot too. It is definately plausible, because even if only a few molecules fuel to burn completely, it will contribute to carbon deposits. But he is probably right, in an engine that is operating at 100%, it isn't going to make any difference except in your wallet.

I would also like to add that higher octane gasoline does not produce more power, it produdes less. Remember, energy doesen't just appear, it just changes forms. The higher the octane, the less energy the fuel contains. Even though the difference is going to be measured in tenths of a mile per gallon, it's still just a waste if your engine doesen't require it.

I thought higher octane meant more energy? Could be wrong though

 

[Eli]

Originally posted by: fyleow

Originally posted by: Eli

Originally posted by: RobCur
The reason for 3 different type of gasoline? there 3 different types of engine.
4 cyclinder, small engine need highest quality like supreme/premium
6 cyclinder, unleaded plus
8 cyclinder, regular unleaded
Very simple.

Do not listen to this person, he has absolutely no idea what he is talking about.

Listen to ZV. Although I will admit I have heard the carbon thing a lot too. It is definately plausible, because even if only a few molecules fuel to burn completely, it will contribute to carbon deposits. But he is probably right, in an engine that is operating at 100%, it isn't going to make any difference except in your wallet.

I would also like to add that higher octane gasoline does not produce more power, it produdes less. Remember, energy doesen't just appear, it just changes forms. The higher the octane, the less energy the fuel contains. Even though the difference is going to be measured in tenths of a mile per gallon, it's still just a waste if your engine doesen't require it.

I thought higher octane meant more energy? Could be wrong though

No. To raise the octane, they use oxygenates like MTBE and Ethanol.

While both substances have high octane ratings, they have an extra oxygen molecule instead of hydrogen(carbon?.. whatever), producing more oxygen to help the fuel burn completely... but not contributing energy.

I am sure someone else can explain it better, heh.

 

[VTEC01EX]

"4 cyclinder, small engine need highest quality like supreme/premium"

Damn, I should have been running 94+ in my Civic the whole time. Motors don't get much smaller than this! ;-) Luckily Honda designed the car to be cost effective to run, so they recommend 87 - no more, no less. 31K trouble-free miles so far.

BTW - I believe higher octane fuels have less energy? It's been a long time since I've read up on this, no one listen to that statement if you're searching for absolute truth!