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Is premium gas worth the premium price?

More people have learned that premium gas has no benefit for cars that don't require it. But even when it's recommended, you still may not need it.

By Stacy Johnson Feb 2, 2011 7:02PM

These days, many people at the pump are passing on premium gas. The reason is obvious: Any kind of gas costs a premium these days. So if you don't need premium, why use it?


While car lovers can debate the merits of using premium, one thing's for sure: Cars that are designed for regular fuel get no benefit from using premium. Using it may not hurt anything -- other than your wallet -- but only specially designed engines can take advantage of premium fuel.

In the following video, I'll drive the point home. Check it out, then meet me on the other side for more.

Despite what you just saw in that video -- that the word "premium" is nothing more than a marketing term -- many people still buy into common myths, like "Premium gives me more miles per gallon" or "Premium fuel will make my car run better." While every company uses a different mixture of fuel additives, and some can give fractional benefits, you won't notice the difference. (For real ways to improve your mileage, take a look at

Another common myth is: "I need premium because it cleans my engine." All fuels have detergents that clean your engine, some better than others. While premium does have more detergent, most fuels will get the job done. NPR's "Car Talk" says it's even OK to use gas from those "el cheapo" stations, as long as you alternate with gas from bigger brands.


There is one "myth" we're reluctant to classify as such, because nobody seems to know for sure. Some people say that using fuel with the wrong octane rating will void a warranty. Both "Car Talk" and say it's not likely but not impossible. This CNN article says Smart USA, at least, will void warranties for regular use of the wrong fuel.

The best bet is to check your driver's manual to see if it says "required" or "recommended." If it's the former, you should probably listen, but if it's the latter, ask a trusted mechanic or consult the manufacturer.


While using premium fuel in a car that's not designed for it is a waste of money, let's talk about doing the opposite, which can save you money -- but also offers a few potential problems.

Using regular-grade fuel in a vehicle designed for premium

Can you do it? Absolutely. Most people should, but there are some exceptions, some precautions you should take, and some minor differences to be aware of.


Using lower-octane fuel with an engine designed for high octane can result in some performance reductions that vary between models, but most people aren't going to notice. We're talking half-second differences in accelerating from zero to 60 miles per hour, and losing some horsepower at racetrack speeds. If those kinds of differences matter to you -- or if you want to learn the tech and science behind your car's fuel -- check out this article from Car & Driver.

There's also a small risk of wearing your engine out faster, a risk that's higher if you're driving a car that's more than 15 years old. Fortunately, you can gauge this risk pretty easily: If it's a problem, your car will start making a sound called "knock," which sounds like it reads. That's a sign that your car isn't handling the fuel well. If you hear it once or twice, you're OK. If it becomes a regular occurrence, you should switch back to premium. Ignoring the problem can cause permanent engine damage.


Most modern cars won't run into this issue, because they have sensors that check how well the fuel is working with your engine and make adjustments automatically.


You're also more likely to face "knock" if your car is under extreme conditions and needs the extra performance -- in higher temperatures with low humidity (the desert), when hauling heavy loads (moving day), going up steep inclines (mountain country) and driving at super speeds (Indy 500). So if you live in an area with these conditions or haul heavy loads for a living, premium might be more important.


But for most of us, "premium" refers to the price, rather than the quality, of gas at the pump. See the links below for more ways to save on gas.


More from Money Talks News and MSN Money:

Feb 3, 2011 7:21AM
Who Writes these articles????IDIOTS,,​,fact of the matter is,,all engines require,a certain amount of timing advance,,,ALL OF THEM,,not a couple,,not just performance engines but all of them.Now,,,the reason you can use low octane fuel and not hear the dreaded "PING",,is because of tiny little sensor,screwed into the side of the engine block,,called,,,you got it,,a "KNOCK SENSOR",,what it does is it senses when your engine starts to ping because of low octane fuel,,and it sends that information to your PCM,,thats the main computer,,and the PCM,,retards the timing,,to stop the pinging,,it doesn't make it any better on your engine,,it just makes it so you don't hear it,,,sorta like turning up the radio.To gain any power,out of any engine,the timing has to be advanced because of the normal engine cycle,,it's the laws of physics,,it can't be changed,,it is,,,what it is,,,well,,anyway,,l​ook,,no one pays attention to me,,I've only been doing automotive repair and building for 40 years,,you do what you want to,,,it's your car,,not mine,,,mine runs great and will continue too,,,yours on the other hand,,well,,it's going to break down and quit,and leave you on the side of the road,,and then someone like me,,is going to fix it,,,and your going to pay me to do that,,and then you're going to go back,,,to doing the same things,,,and you're going to keep breaking down,,,well,,,you see where I'm going here,,yea,,go ahead and put that cheap gas in your vehicle,,because,,it​ keeps putting the good stuff in mine,,,OH,,and thankyou
Feb 3, 2011 11:20PM
Richard Kingston - You have very valid points and I concur with you. My little 4 cylinder car (not a piece of junk like lonelyfather76 likes to insult us with) DOES get better mileage and it DOES perform better with premium. The car doesn't work as hard going up a hill and it takes noticeably less gas pedal to motor down the road. I have proved it to myself with an extensive spreadsheet over the last 5 years that I've had this car since brand new. Every drop of gas has been charted and calculated. Here's the kicker about it. Using regular or using premium, the actual cost is almost the same. Premium costs more but I get better MPG.

to lonelyfather76, this article is stupid and so are you. "Premium fuel causes a weaker spark"??? Are you kidding? That's the stupidest thing I've heard all week. Get off the kool-aid. I have more respect for Richard's 3 cylinder car than I will ever have for a jerk like you.

This article is pure cow-dung and Stacy Johnson should not be allowed near any keyboard. She doesn't know the difference between fact and fiction. Myth, indeed. <eye roll>

Feb 3, 2011 11:29PM
I have no idea if there was a choice in the matter, but I absolutely think its totally rude for a video to automatically start up when entering here. I'll be the one to decide if/when to play the video, thank you very much.
Feb 3, 2011 10:52AM
Somewhat related to this; both my small engine (chain saw, atv, mower, etc) and auto mechanics say that ethanol clogs up fuel systems and that a fuel conditioner should be used when using ethanol. The auto mechanic says that going up a fuel grade "may" help with this issue. There is one local gas station which sells ethanol free fuel and that's where I buy gas now. Time will tell, I suppose.
Feb 4, 2011 8:52AM
On average my 1997 Ram 1500 with V8 magnum engine gets 13 to 14 MPG with the cheap stuff (87 octane) and 18 to 22 with high test (95 octane) and a lot more power. (highway in Mo.) I don't know where they get their stats but after 11 years with this truck, I'll stick with the good stuff for 20 cents more.
Feb 3, 2011 12:58PM

Always thought the premium gas requirement was just propaganda from the oil companies until I bought a Cadillac SRX with a Northstar V8.  After running just a couple of tanks of mid-grade the check engine light came on.  This was not a one-time deal, but consistently.  While I love the horsepower, hate that there’s no alternative but to buy the high-end grade.  Unless you have money to burn – be warned sometimes there are no options if you want the performance and not a trip to the dealership!

Feb 3, 2011 11:30AM
this is hard to believe when exxon just grossed 53% more income than last year.  obama should really get his head out of his a$$ and start drilling off the coast's. and stop selling out oil to other countries.
Feb 3, 2011 8:42AM
I agree with katbite. I also am a 40 year automotive repair technician. Carbon & sludge is a by product of low octane/poor fuel & low quality products. All fuel is mainly the same except for filtering & detergents. Vehicles are made better these days & will last longer. However, if not maintained & use proper products you will see break down approximate 125,000 mile or before depending on your lack of care. Most people would agree they need to change oil on there vehicle regular. What about the other fluids? Same difference. You can run after cheap for awhile, but when your vehicle breaks down you will be running & the cost is greater.
Feb 3, 2011 6:06PM
And to Richard Kingston... lol you have a 3 cylinder car and want to argue over this? Seriously?  You, in your junk car, are absolutely wasting money.  Fact: Premium fuel causes a weaker spark, aka less power, if your car cannot maximize the octane. So unless you changed your spark plugs to a higher spark, you are blowing money.
Premium in a 3 cylinder... now that is a bigger joke than this article. Does a high performance V8 benefit from premium? Yes. Your junk? No.

I always fill with 90 octane because it improves my mileage 4-5 mpg. 
Feb 4, 2011 12:47PM

@Rescueguy:  you're right about the timing being retarded due to the knock sensors.  But you have to consider the effect of what happens to your engine when the timing is retarded.  Basically, your engine's cylinders are firing at the wrong point in their cycles, which creates stresses in your engine for which it wasn't designed.  Over time, that may lead to a very expensive repair.  If you have a low compression engine, regular gas is fine.  But if you have a high compression engine that was designed to use premium gas, you should stick with it.


Feb 3, 2011 3:53PM
Curiously, as gas prices increase, the penalty of going premium as a proportion of the total fuel bill decreases. This is because most stations only charge 10c difference between grades (20c to go from Regular to Premium).

When Regular was 1.50/gal, Premium was 1.70/gal (13.3% more)
Now that Regular is 3.00/gal, Premium is 3.20/gal (6.7% more)

There are some stations that are charging 12-13c between grades but most of them seem to be sticking to the old static formula. It's a relative bargain for those who must use Premium.
Feb 3, 2011 6:01PM
Another garbage article that had no reason to be published.
Feb 4, 2011 3:51AM
okay -- I am a master tech and race both cars and bikes. Higher compression engines will suffer ping , knock or what is know as pre-ignition. Octane actually reduces the flammability of the fuel to stop it from igniting before it is supposed to. The article is factual -- don't use premium unless you need it (per manufacturers recommendation). Even if premium fuel is recommended knock sensors on the car will retard the timing to keep engine damage from happening when using low octane fuel. Seriously, do what you want tho, its your car and your money. As long as I am not having detonation issues I will not run higher octane than needed.
Feb 3, 2011 10:06AM

Furthermore... how much "regular" and "premium" is produced from a barrel of crude is variable, but the fuel is separated through fractional distillation, and it is possible to produce spark-ignition fuels with different performance characteristics. I am sitting next to machines/instruments, CFR engines, where the R+M/2 number comes from...


That guy is an idiot. I use premium in my tiny 3-cylinder, manual car for two reasons. A) the mileage is better, depending on driving style, 5-10%, and B) the low-end torque is produced more gently on the piston/crankshaft bearings.


Octane is a measure of how smoothly the fuel burns. At lower RPM's, you do get more power. In a normal engine.


I'll be glad to argue this with anyone, provided the understand the words I just typed.

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