It’s True: Premium Gasoline Is A Lot Like Male Enhancement Drugs

The things I do for this blog in the name of personal finance.

One day last month I got into a lunchtime conversation at work with a contractor who tried to convince me he had good reasons for putting premium gasoline in his Toyota Corolla, the biggest of which was that he got better gas mileage.   I found that a bit hard to believe – but more on that in a second.

For the record, Consumer Reports notes that using premium gas in an engine that is designed to run on regular does NOT improve performance.

Unlike my contractor friend, I think most people understand that premium gasoline is generally meant for use by high performance cars and the occasional Sherman tank.   Still, in 2007 the market share of premium gas was almost 10 percent.

I don’t know about you but, regardless of how you calculate fuel economy, one out of every ten cars I see on the road aren’t high performance vehicles — or Sherman tanks for that matter — so anecdotal evidence suggests a lot of people still believe in the magical powers of premium gasoline.

In fact, the magical powers that allow premium gasoline to turn a Toyota Corolla into a 540-hp Shelby GT500 is eerily similar to the claims of those male enhancement drugs that promise to turn us average Joes into superhuman love machines that would make even the late great Barry White envious.   I mean, just look at the evidence:

Premium Gas

But I digress.     Let me go back to the contractor who swears he gets better gas mileage.

In addition to prolonging the life of his engine, this guy swears premium gas gives him an extra three miles per gallon too.   Assuming he gets 40 miles per gallon, that would result in an improvement of only 7.5 percent, which is very close to the mark-up for premium gas anyway.   Fine.

So just for grins I recently completed my own month-long experiment using only premium gasoline in my 1997 Honda Civic.   I already had plenty of gas mileage data using regular gas from a previous analysis I did of my new work commute.     For the record, I was averaging 40 miles per gallon using regular gasoline over a roughly two month period.

The results?   Well, over the past month I averaged one mpg less (39 mpg) using the premium gasoline and paid an additional $6.44 over that period for the privilege.   Talk about feeling like a chump.

I’ll bet a lot of suckers people who bought those magic pills felt the same way after they finally, er, measured their results too.

The lesson here is don’t buy into the hype of thinking that just because something cost more it has to be better.   Premium gasoline is intended for use on a very narrow niche of cars.   If you aren’t sure what type of fuel your car should be using, check your owner’s manual.

The odds are the manufacturer probably recommends good ol’ regular 87 octane gasoline.


  1. 1



    I’m no expert on gasoline. But, here is the reason for premium gas. It’s higher octane rating menas that it has a higher detonation level. It is designed for performance cars that have higher compression. Regular fuel may pre-detonate or “ping” in a performance car, which can damage the engine. Premium has no extra benefit in a car with lower compression, besides possibly some cleaning additives.

    It is my understanding that premium fuel actually has fewer BTUs per gallon than regular, so it should yield lower mileage. (Which was verified by your testing.) Diesel fuel has even lower octane and higher BTUs per gallon than gas, which is why diesel engines get better mileage and terrorists use it in fertalizer bombs.

    • 2

      Randy says

      Gasoline is actually a collection of a bunch of different hydrocarbons. Short chain (fewer carbon atoms molecules) vaporize more quickly and at lower temperatures. “Regular” gas, and winter blends have more of these, and less of the more stable longer chain molecules. “Octane” is actually an eight carbon molecule used to benchmark the result of a batch from the refinery.

      I’m not too sure about actual BTU content. The key feature of premium is that it will not ignite at higher cylinder pressures until the spark occurs. So, no knock or ping which causes a loss of power and may actually result in engine management changes in modern computer controlled engines.

      An older car may benefit from higher octane gas if it has carbon built up on valves and the pistons. This serves to increase the compression ratio to make it functionally more like a performance type engine. That is how it may be possible to get better mileage when using higher grades of gasoline.

  2. 3

    Kelly Browning says

    You certainly can’t be accused of misleading advertising… your blog really is off-beat. And I don’t mean that in a bad way! So can I assume the mid-grade gas is also a waste?

    • 4


      @Jesse: You know, you are SO right about that. Great point, my man! I wondered why the states have different octane ratings, and according to Wikipedia it has to do with elevation above sea level. “Octane ratings can vary greatly from region to region. For example, the minimum octane rating available in much of the United States is 87 AKI and the highest is 93. In the Rocky Mountain (high altitude) states, 85 octane is the minimum octane and 91 is the maximum octane available in fuel. The reason for this is that in higher-altitude areas, a typical combustion engine draws in less air per cycle due to the reduced density of the atmosphere.”
      @Kevin: Designer jeans are another item that rarely justifies the added expense. Other than a designer tag, just what ARE people getting when they pay four times more money for a pair of denim that is virtually identical to the no-name brands?
      @Bret: You are right, Bret. I’m not a chemist but, what I’ve been reading, in order to increase the octane they have to add other chemicals that end up lowering the BTUs per gallon, which drives down your mileage.
      @Kelly: No false advertising here! What you see is what you get. LOL I would assume anything over and above the manufacturer’s recommendation is a waste. Fun fact time: I was told by a gas truck driver who was filling up the underground tanks at my local gas station that the mid-grade gas is simply mixed at the pump from premium and regular gasoline. I always thought there was a separate underground tank of mid-grade, but apparently not. ;-P

  3. 5

    James says

    entertaining as always.

    in regards to mid grade, a friends dad always uses the mid grade but he found out about the mixing at the pump and now mixes his own. He pumps 50% regular amd 50% premium giving a blend all his own.

    maybe your next test should involve those male *ahem* enhancers. Sorry I won’t be available to be part of the panel however LOL

  4. 6

    Greg Patterson says

    Awesome story. I’m still sad that my Audi requires premium, but now I can really make fun of my friends whose cars don’t need it.

  5. 7


    I asked so many experts. Everyone of them said whatever the manufacture says to use, you just use that. If the car is made for regular unleaded, don’t use anything else. If you use different grade than the manufacturer’s, more carbon gets deposited in the combustion chambers and that ain’t good.

    Check your manufacturer’s manual and use exactly the same grade as the book says.

  6. 9


    What I find just as interesting as your findings here is that the term “premium” varies by state! In California, the different octane ratings are different than in Utah, so the lowest octane for Cali, 87, is higher than the lowest octane rating for Utah, 85. There is no standardization here!

    • 10

      Randy says

      In your case, it is a function of altitude. Cars work well at higher altitudes with lower octane gas. And, you save some money. It all has to do with pressurization of the air/fuel mixture in the engine’s cylinders and the resulting burn character.

    • 11

      Ry Ry says

      I get 50mpg from my civic coupe of the same year, manual, never using ac, running bp 98 octane premium fuel

  7. 12

    James says

    LOL- great post. i couldn’t agree more why do people not just conduct there own research. its like if you tell someone that it works they automatically think it works. now i understand the power of word of mouth marketing but come on. premium gas, what a rip off.

  8. 13


    People think they’re getting something better because they’re paying more. They’ll pay the higher price and tell themselves they’re doing better by it, facts be damned.

    It’s not until you’ve been burned a bunch of times by hype that you begin to recognize an upsell. In the meantime, you go about happily paying more, thinking more gets you the better stuff. Sometimes maybe, but nowhere near all the time.

    Heck, look at all the people who drink bottled water? I’m a dope working for a living when I’d be relaxing on a beach in the tropics if I’d hadn’t been too common to realize that a whole lot of people would pay a premium for something they could get for free, just by putting it in a bottle and calling it “Le Water”.

  9. 14


    Yep, I do the regular gasoline. I don’t buy the hype on the premium stuff. I’ve had plenty of people who know cars and have told me to just stick w/ the regular!

  10. 15


    This analogy absolutely made my day. I see why your blog was voted as one of the 7 best in 2009. I remember years ago when my husband drove either a Cadillac or a Lincoln. Both absolutely needed the high performance gasoline. Then I purchased a smaller car and so as not to feel bad about not using the high performance, I switched down to mid-grade and then occasionally felt like I needed to mix the two. Considering the regular as an option didn’t dawn on me. The light bulb finally went off and for years I have used only the regular without any adverse reactions. With gas prices continuing to escalate, even switching to mid-grade is not a considered alternative.

  11. 16


    I love Consumer Reports. It’s a magazine I like to check out before making large purchases. I’ve never paid for premium gas, my Honda doesn’t need it. Good to know I haven’t been wasting my money!

    • 17


      @James: Thank you! BTW, I’m just curious why your friend’s dad mixes his own blend when it is done automatically at the pump? I guess savvy consumers could do that if they noticed the price of mixing the two octanes was cheaper than the mid-grade price.
      @Greg: Tell them why they’re blowing it and then have them buy you beer because of all the money you’ll end up saving them in the long run. Heck, if I continued my little premium gas experiment for a whole year, I would have wasted over $75 – assuming prices stayed the same.
      @20s: Good man!
      @Lillie: It is really amazing how much money people throw away over the years buying over-priced premium gasoline. Then again, before I get too smug, I will say I still catch myself paying more for name-brand grocery items simply out of habit when a lot of times the store-brand is just as good if not better.
      @LittleHouse: I like Consumer Reports too. I think it would be a blast to work for them! You think they’d hire me? 😉

  12. 18



    What if your car (Saab 9-3) recommends AON 90 for ‘optimum performance’? Think I should mix the 89 and the 91 that California offers, or be lazy and stick with the 91?

    Or should I let the knock sensors in my car scale down the boost and just get 87? Haha, decisions, decisions!

  13. 20

    Bob L says

    Finally one person mentioned knock sensors.

    In older cars, the state of tune was set, and if your car knocked, you had to use a higher octane. I had an old Toyota that had a small dial on the distributor cap that allowed you to make fine adjustments to the timing. That way, you could use whatever gas was available, and adjust for no knock.

    I have done a fair amount of testing in this area, with both motorcycles and cars. Trying to stay with the same gas station, and similar driving. My experiences show that each vehicle varies in mileage with different grades, some more than others. For example, my car gets it’s best MPG on regular. One bike gets it’s best mileage on premium, and one bike gets it’s best on mid grade. I have kept lots of records over the years, and looking at them shows similar conditions with other vehicles.

    That being said, in NO case did the increased mileage justify the increased cost. So, it still stands that the only good reason to use premium is if your vehicle knocks with regular or midgrade.

    I use regular in the car and one bike, but vary the grade on the other bike based on typical temps. It will ping with mid-grade if it is VERY hot, and will ping with low test unless the temps are fairly cool. So, Hitest in the summer, low test in the winter and mid to low in the fall and spring.

    • 21


      Thanks for the comments, Bob. I’ve noticed my Honda Civic has been pinging a bit over the past couple weeks. Could hot weather be responsible for pinging car engines too, or does that apply only to motorcycles?

      • 22

        Bob L says

        Lots of things can make an engine ping. Pinging can be bad. An occasional light pinging is not a disaster, but it is not good for the engine.

        Yes, an engine will be more likely to ping in hot weather. Assuming your engine is in a good state of tune, and there are no issues like old dirty spark plugs, or oil deposits or carbon build up, then, yes, it is probably the hot weather. But it could also be the gas. Try a different station. If you need a higher octane, then don’t just add a little gas to your tank, wait until you need at least 3/4 of a tank. The reason for this is that many stations use just one hose, and if you are getting only a small amount, and the last guy got regular, the first gallon or so will be his regular as there is fuel in that single hose. This is obviously more of an issue with bikes, and I really can’t understand anyone getting only a little gas at a time in a car, but that’s just me.

        Other things that can have an effect is altitude and even time of year. So if you fill up with regular in the mountains, and then go to a low land desert, you might get pinging. I have had this happen.

        The fuel formula’s change during the course of the year in many areas. Here in the northeast, they have to worry about cold starting in the winter and vapor lock in the summer. Sometimes, if you are on the edge of pinging, the change in formula can bring you over the edge.

        What year is your Civic? If I remember right (I seldom do….), the Civic has some kind of lean burning engine that allows for better MPG. But it also has a knock sensor, that should compensate for octane at least a little bit. I don’t think your car should be pinging.

        How old is the gas. I am assuming you don’t drive your car much (I’m a new reader and assume a lot). The new scam….er I mean alcohol gas, goes “bad” sooner. Some will say as quick as two weeks, but I have used gas that was 6 months old so, I would not worry too much about it, BUT as it ages, it does become a lower octane. This may be the only time I might suggest NOT filling your tank, if you only drive a little and don’t use your gas fast enough to keep it from going bad. I put 5,000 miles on my car a year, almost all in the winter, but I have not had a problem with old gas, other than some pinging.

        If your car is older and does not have all the computers, and has a carb, you can tune it to run well enough with almost any gas.

        Long post, especially considering I have not had any coffee….. So, try another pump and see if the problem goes away. Or switch to a higher octane in the hottest weather, or see a mechanic and make sure your car is OK.

        Bob L

        • 23


          Thanks for the tips, Bob. I keep my car in great shape and meticulously serviced. I just got it serviced last week and then the pinging started – but so did the really hot weather. So it’s tough to tell what happened. I have a 97 Civic, stick shift. I drive it about 350 miles per week. I just filled up my tank last night, so we’ll see if I had a “bad” tank of gas.

  14. 24

    Ken says

    You’re absolutely right that putting high octane gas in a car that is designed for low octane gas is completely wasteful, but you don’t have to have a 500+ HP monster to drive a car designed for premium grade fuel. Many 2-300 HP cars are tuned for 91+ octane.

    Any recent car that is designed for high octane will have a knock sensor and can safely run on lower octane gas, however if the knock sensor kicks in, you will lose efficiency. Driving a car designed for high octane fuel on 87 octane will result in lower mpg. On the flipside, as you discovered, running a car desinged for 87 octane on high octane fuel will just drain your wallet faster.

  15. 28

    Thomas says

    Never thought of comparing gas to well say male enhancement drugs but I guess it works. I hate to say most of the cars I have been driving requires high octane. Though I dont think it should make a difference I have notice how my cars act when I didnt put the require octane in the tank.


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