what is the best gas?

[manning]

Is premium gas better than regular gas

 

[low-key]

what ever cost the most is the best

 

[rwdavis2]

No, premium is not better than regular. IF your car says to use regular, premium will not make anything better.

 

[Poohforyou]

No, premium is only good for cars that require it.

 

[tvguy]

Not better, not worse, just different. All new cars* by law have to run on regular without damaging the engine, but some automakers recommend premium for better performance.

*Only new cars exempt to the regular gas rule are those that less than 500 will be sold in the U.S. ( exotics like Ferrari, Maserati, Lambordini).

 

[bcla]

All things being equal, there's nothing about the base fuel that would make premium better. It's certainly better for certain types of engines that are designed to use it. That being said, some sellers might have premium gas with higher levels of detergent additives, although that's not always the case.

Also - for the most part gas is gas. The "base fuel" is sold/traded/transported almost exclusively as a fungible commodity. There are some exceptions, but it would cost way too much to try to force the logistics such that the fuel sold at a specific pump comes from a specific supplier. That's not to say there can't be differences, but they're not terribly meaningful. There may be differences in detergent additives added at the racks for delivery to a specific branded gas station or at the gas station. However, the base fuel is almost always a fungible commodity and comes from whatever refinery happened to send it to a pipeline distributor. It's a lot like electrical distribution on a grid. Their contracts require them to accept so much fuel from a refinery and deliver the same amount of fuel to fuel terminals. The input fuel meets a certain requirement and what they deliver can be the fuel from another refinery. If I buy gas from a Chevron or Valero station, the fuel might have been from a Shell or ExxonMobil refinery, or possibly a combination.

And there's a lot more than just the 87/89/91 octane (R+M)/2 that most people see at pumps. There's such things as 93/94 octane "super premium" that's recommended for some high-performance cars. If you get really crazy there's 100 octane racing unleaded.

 

[DisneyOma]

Oh, you're asking about gasoline....

 

[Gracie09]

Not better, not worse, just different. All new cars* by law have to run on regular without damaging the engine, but some automakers recommend premium for better performance.

*Only new cars exempt to the regular gas rule are those that less than 500 will be sold in the U.S. ( exotics like Ferrari, Maserati, Lambordini).

There is no such law. I am currently researching my next car and the acuras, bmws, lexuses, and some mazdas all require premium. Well they don't require it but if your engine starts knocking there goes you warranty unless you have used premium. These are new model year cars.

 

[NewRVLady]

we had a couple cars that required premium-back when gas was expensive, it could be a big jump in price-in some areas

I am glad the 2 we have now use regular

 

[Dan Murphy]

Premium gasoline has a higher octane rating than 'regular'. Higher octane rated gasoline helps the gasoline not to pre-ignite in the cylinder combustion chamber, due to high heat created by high compression engines, before the gasoline should ignite from the spark plug firing at correct time. If an engine has pre-ignition, it will 'knock' and may be damaged. At a minimum, performance/mileage would be hurt. Years ago, before computers ran automobile engines as they have for many years now, premium was required in many cars. With the computers in cars today, pre-ignition is eliminated from all but the most exotic of cars. Some main stream manufacturers of higher end, more costly cars (they may have higher compression engines), may recommend premium, but I do not think there are any that actually require it today. The computers will prevent almost all pre-ignition.

 

[dclpluto]

My mom had a car that didn't run right on 87 she had to get 89 than it ran fine.

 

[bcla]

There is no such law. I am currently researching my next car and the acuras, bmws, lexuses, and some mazdas all require premium. Well they don't require it but if your engine starts knocking there goes you warranty unless you have used premium. These are new model year cars.

Most modern engines have knock sensors and timing systems that can pull back timing to prevent damage. This comes at the cost of performance and fuel economy. If they didn't, there would be huge class action lawsuits. If they fail during the warranty period, failure to use premium wouldn't work as an excuse to deny a warranty claim.

 

[bcla]

Premium gasoline has a higher octane rating than 'regular'. Higher octane rated gasoline helps the gasoline not to pre-ignite in the cylinder combustion chamber, due to high heat created by high compression engines, before the gasoline should ignite from the spark plug firing at correct time. If an engine has pre-ignition, it will 'knock' and may be damaged. At a minimum, performance/mileage would be hurt. Years ago, before computers ran automobile engines as they have for many years now, premium was required in many cars. With the computers in cars today, pre-ignition is eliminated from all but the most exotic of cars. Some main stream manufacturers of higher end, more costly cars (they may have higher compression engines), may recommend premium, but I do not think there are any that actually require it today. The computers will prevent almost all pre-ignition.

Deonation (spontaneous explosion of the fuel air mixture under pressure) can be more serious than pre-ignition, which would require a heat source. With detonation, the spark sets off the mixture, but the pressure and heat causes it to spontaneously explode away from the initial explosion. It's not always destructive but can be past a certain threshold. You hear that knock sound which can be normal to some degree, but can be destructive if under a heavier load. A higher antiknock rated fuel can resist detonation better.

http://www.contactmagazine.com/Issue54/EngineBasics.html

 

[Malibustyle23]

There is no such law. I am currently researching my next car and the acuras, bmws, lexuses, and some mazdas all require premium. Well they don't require it but if your engine starts knocking there goes you warranty unless you have used premium. These are new model year cars.

How would they verify that you only used premium gas? You're not supposed to keep every has receipt, right?!

 

[bcla]

My mom had a car that didn't run right on 87 she had to get 89 than it ran fine.

That can happen with older engines. Not so much with newer engines with knock sensors and engine management systems that pull back timing. However, those systems have their limits and sometimes a higher octane fuel is the only thing that helps short of an engine rebuild.

 

[Gracie09]

How would they verify that you only used premium gas? You're not supposed to keep every has receipt, right?!

The computers in the new cars can determine the octane. They down load the codes. They can also test the gas in the tank. If I am dropping 50k + on a car and I want it to last, the extra 20 cents a gallon isn't really much of a consideration. Besides, most of these cars get better gas milage at the higher octane. So by putting the cheaper stuff in, I am really costing myself money.

If the manual requires premium, you should use premium. If it is recommended, that's up to you.

But to my original post, contrary to tvguys post, there is no law banning manufacturers from requiring premium.

 

[bcla]

The computers in the new cars can determine the octane. They down load the codes. They can also test the gas in the tank. If I am dropping 50k + on a car and I want it to last, the extra 20 cents a gallon isn't really much of a consideration. Besides, most of these cars get better gas milage at the higher octane. So by putting the cheaper stuff in, I am really costing myself money.

Where'd you hear that about testing the fuel in the tank? A real test involves using a comparison to a reference fuel composed of iso-octane and heptane, and these can only be tested by applying real conditions on a physical setup.

What an engine computer can do is use the knock sensor to detect the onset of knock and retard timing to prevent knock from getting excessive. It's a reactive system that's always adjusting. There's the possibility of a poor mixing of fuel in the tank and the effective octane rating changing as different fuel is taken into the fuel system.

An engine computer can definitely record when maximum retardation of timing is encountered. That would be pretty bad. However, it's unlikely for a modern engine to get to that point.

 

[tvguy]

Most modern engines have knock sensors and timing systems that can pull back timing to prevent damage. This comes at the cost of performance and fuel economy. If they didn't, there would be huge class action lawsuits. If they fail during the warranty period, failure to use premium wouldn't work as an excuse to deny a warranty claim.

Exactly/

 

[tvguy]

There is no such law. I am currently researching my next car and the acuras, bmws, lexuses, and some mazdas all require premium. Well they don't require it but if your engine starts knocking there goes you warranty unless you have used premium. These are new model year cars.

The Clean Air Act requires that all mass produced cars sold in the U.S. operate safely on regular grade fuel. Only limited production cars where they will be selling 500 or less are exempt. Yes, Acura, BMW, Lexus and Mazda RECOMMEND premium, but they do not REQUIRE it. Funny, how the exact same engine in a Lexus recommends premium, but when installed in a Toyota, the recommendation is regular..

 

[Gracie09]

The Clean Air Act requires that all mass produced cars sold in the U.S. operate safely on regular grade fuel. Only limited production cars where they will be selling 500 or less are exempt. Yes, Acura, BMW, Lexus and Mazda RECOMMEND premium, but they do not REQUIRE it. Funny, how the exact same engine in a Lexus recommends premium, but when installed in a Toyota, the recommendation is regular..

No it doesn't. It requires certain cleaner burning fuels which are usually achieved by additives to regular gas. The Acura RDX and every model of mini cooper require premium. Not recommend but require.