what's the difference between regular and premium gas?

Question

if I drive a VW Jetta 2.5, does it make a diff to use premium gas? is it true that it's better for the engine to use premium when the weather is hot?

Answer 1

the octaine rating, i would use the premium because it will run better and keep your engine cleaner, the fuel system and spark plugs that is, the valves also, plus give a little more power, i know it says in the owners manual that 87 will make it run ok but i never run it as it makes my vehicle run like s..., your jetta will thank you for the better fuel,

Answer 2

Two thing is difference. First is usually the cost. Premium is usually a little higher the regular. Second is the octane number. Premium has a higher octane number than regular. If your car is under warranty and it says to use a certain fuel you probably should use it because if they can show you used a different kind it could void your warranty. Probably won't do any harm to your engine, might not have the zip it has on premium or it might make a little noise. Some engines run better on premium and others run ok on regular.

Answer 3

Premium gas has higher octane rating than regular. A VW Jetta should be run on premium as they're designed for it.
Octane rating is the 'anti knock' rating of a motor. As the compression ratio is raised, so a motor tends to 'knock' or pre-ignite the cylinder charge. This can cause severe damage to a motor. The VW Jetta has anti knock sensors which adjust the motor spark timing to prevent this happening, but it still causes a downgrading of performance. The extra cost of the premium fuel will be offset by the better fuel economy and power using it.

Answer 4

NO it does NOT
"High Octane" is not synonymous with "good" or "better", and does not mean that it is better for your engine! And the chances are pretty good you don’t need high octane fuel in your scooter.

High-octane fuels only become necessary when your engine has a high compression ratio. It’s a very long and complicated story…

First important fact that you must accept:

All gasoline, regardless of its’ octane rating, have pretty much the same amount of energy per gallon. What!!! "Sacrilege" you say? Well, actually, some higher-octane fuels have a few LESS percent energy per gallon…so as not to argue over this small point, for the sake of this discussion we will all agree that the automotive gasoline that you buy at the pump, regardless of octane rating, has the same amount of potential energy.

Second important fact that you must accept:

Octane is NOT a measure of power but of the fuels’ resistance to ignition from heat. A higher-octane fuel, under identical combustion chamber conditions, will burn slower.


The piston, quickly squeezing the fuel/air mixture into a small space, can generate enough heat of compression to ignite the fuel well before the spark plug fires, with unpleasant results. If the fuel prematurely ignites while the piston is on its way up, the burning of the fuel, in conjunction with the rising piston, creates even more pressure, resulting in a violent explosion. This explosion is equivalent to hitting the top of the piston with a very large hammer. If you want to be able to see through the top of your piston, ignore those sounds that are usually called: "pre-ignition", "ping" or "engine knock".

What we really want is a very rapid burn of the fuel, not an explosion. And we want the burning of the fuel to take place while the piston is in a better position to convert this pressure into productive work, like on its way down. Think of this burning as a very fast "push" on the top of the piston. Despite the violent noises you hear from some exhaust systems, it really is a rapid push on the top of the piston making the crankshaft go around, not explosions.

So that we can ignite the fuel at exactly the right time with the spark plug, instead of from the heat of compression, they put stuff into gasoline to keep it from igniting prematurely. The more resistant the fuel is to ignition from the heat of compression, the higher its octane rating.

Are you with me so far?

Higher compression ratios = higher combustion chamber pressures = higher heat… and it is with these higher combustion chamber temperatures that the magic happens.

At higher temperatures the fuel is burned more efficiently. So, while it’s true that the higher-octane fuel does not posses any more energy than low octane fuel, the increased octane allows the extraction of more of the potential energy that has always been there. Conversely, lower compression ration engines utilize a little less of the fuel energy potential (2-4% reduction) but there is also less heat generated in the combustion process.

So how do you know if you need high-octane fuel? look in the owners’ manual! Manufacturers really do want you to get the maximum efficiency out of your engine. They do their best to give a good balance between horsepower and engine life. It’s in their best interests to do so.

There is ABSOLUTELY NO BENEFIT to using a higher octane than your engine needs. The only benefit is increased profits to the oil companies that have cleverly convinced some of the public that their new "Super-Duper, Premium-High-Test, Clean-Burning, Used-By-Famous-Racing-Types-All-Around-The-World, Extra-Detergent-Laden-Keep-Your-Pipes-Clean, Extra-High-Octane" fuel is your engines’ best friend. don’t listen to that talking cartoon car.


If all is well and correct, and you still are getting knocking, then try the next higher octane. You won’t go faster, you won’t go farther, but you will prevent an unsightly hole in your piston.

Answer 5

It shouldnt matter what kind of gas you should use, the only difference between the two is the octane rating. Most new cars all use regular and premium is not necessarily better. It would make a difference in higher performance engines.

the weather doesnt make a difference on gas use, althouth there is a difference between summer gas and winter gas. Winter gas contains more ethanol which raises the freezing point of gas.

Answer 6

Everybody has mentioned higher octane but nobody has said what it is. Octane is the measure of a gasoline's resistance to explode prematurely. Early burning of gas is called detonation and is called knock or pinging. Higher performance engines have higher compression ratios and need premium gas to produce all the power they are rated for without detonation. Most engines have lower compression and are fine with regular gas.

Premium gas has nothing to due with resistance to gunk buildup. Good quality regular gas has detergents and cleaners too. Cheap gas of any grade does not.

Answer 7

Yes it is true premium is better when the weather is hot. I would advise that, if you can afford it, buy premium gas. Premium is better for your engine. Guaranteeing a better ride and longer time of use. Regular gas will leave a type of "gunk" in your engine that will require a lot of work and eventually clog up your tubes. This is very important, especially for the type of car that you have. Smaller cars are much more vulnerable to "gunk buildup".
I hope this helps.

Answer 8

About 20 cents a gallon. It isn't necessary to use Premium gas except in high performance cars. The newer cars adjust themselves to the octane level you put into the car. Therefore if you put in Regular gas your engine will adjust itself to that octane. Also check with your mechanic, or read your Owners Manual.

Answer 9

Nope. Premium just has a higher octane rating and doesnt help a car designed for regular. Use whatever gas the manufacturer recommends.

Answer 10

Not sure about the Jetta but beans will give you regular gas. If you want the premium you gotta through a little raw brocholi and budweiser in the mix.