Save money on gas and protect the environment

Today I was listening to Car Talk on NPR while driving, coincidentally, a car. Those guys are always good for some laughs, and sometimes I even learn something new about automobiles. Today was one of those days.

Tom and Ray Magliozzi (aka the Tappet Brothers) were in adamant agreement that most people should use regular gasoline, rather than premium, no matter what car they drive. They stated that the difference in performance is negligible (unless you’re racing), regular gas costs less, and premium gas may contain higher levels of MTBE (which can contaminate drinking water).

Hearing that made me go, “Huh?” I had always been told that using a higher octane gasoline would help prevent knocking and keep your engine running cleaner. So I decided to do some research.

Does your car need premium gas?

The FTC says to go with what the owner’s manual says, but that the usual octane recommendation is met by regular gas. However, Edmunds.com explains that for about the last fifteen years, on-board computers have been able to regulate knocking even at lower octane levels than are recommended by the manufacturer. And regular gas appears to run just as cleanly as premium. Both state that if your engine begins to knock, you should increase your octane level — but otherwise, go for regular.

What’s the fuss over MTBE?

MTBE is added to gasoline to raise its octane level and to oxygenate it. Oxygenation helps to reduce carbon dioxide emissions of pollutants, so the EPA encouraged the use of MTBE — until they found out that it’s also a carcinogen that mixes easily with ground water, and it often leaks from storage tanks.

Not all gasoline contains MTBE — some US states have already banned its use, and manufacturers are beginning to phase it out in preference for the more expensive (but not carcinogenic) ethanol. But if you live in an area that does allow MTBE, premium gas is likely to contain more of it, in order to raise the octane level.

The money

In the US now, the price of premium gasoline can be as much as 30 cents a gallon more than regular. That means that you could save three or four bucks on your average fill-up by switching to regular gas. If you fill up once a week, you could save $150 – $200 a year.

Fitting topic for [GAS], don’t you think? Given the information above, I’m ready to switch to regular — at least until someone comes a-knocking under the hood. How about you?

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24 Responses to Save money on gas and protect the environment

  1. Your post says "Oxygenation helps to reduce carbon dioxide emissions, so the EPA encouraged the use of MTBE", but is that the correct reason? The linked EPA page about MBTE, seems to say that MBTE is added primarily to reduce polution/smog (carbon monoxide, ozone, etc).

    Of course, a cleaner burning fuel is more efficient, so less carbon dioxide is output per mile driven – but that isn't why the EPA encouraged the use of MBTA. In fact, the EPA has refused to regulate carbon dioxide emissions.

    Ironically, just this week the Supreme Court ruled that the EPA must regulate carbon dioxide just like all other pollution covered by the Clear Air Act.

  2. I listened to their show today too! I recently purchased a car (a '95 Totota Avalon XLS) and was told by the owner to only fill up with premium gas. When I filled it up the third or fourth time I accidentally filled it with regular without noticing until I printed the receipt. At first I was worried that my car might stop in the middle of the road and fall to pieces but I was pleasantly surprised when nothing of the sort happened and the car ran normally. The next time I pumped gas I used premimum and again I didn't notice any remarkable differences. Since I haven't been racing my car I haven't needed the extra octane so I guess the $150-200 savings per year will do me well if I switch to regular permanently.

  3. I listened to their show today too! I recently purchased a car (a ’95 Totota Avalon XLS) and was told by the owner to only fill up with premium gas. When I filled it up the third or fourth time I accidentally filled it with regular without noticing until I printed the receipt. At first I was worried that my car might stop in the middle of the road and fall to pieces but I was pleasantly surprised when nothing of the sort happened and the car ran normally. The next time I pumped gas I used premimum and again I didn’t notice any remarkable differences. Since I haven’t been racing my car I haven’t needed the extra octane so I guess the $150-200 savings per year will do me well if I switch to regular permanently.

  4. If your car was designed to run premium gas, running a lower octane may cause your car to run less efficiently, leading to decreased performance and increased fuel usage. The amount of impact this has is dependent on a large number of conditions including how optimized the specific engine is for a certain type of fuel. I drive a 96 Nissan Maxima and using regular fuel results in decreased performance and at least a 10% decrease in fuel economy. It's probably best experimenting with your specific car before proceeding.

  5. If your car was designed to run premium gas, running a lower octane may cause your car to run less efficiently, leading to decreased performance and increased fuel usage. The amount of impact this has is dependent on a large number of conditions including how optimized the specific engine is for a certain type of fuel. I drive a 96 Nissan Maxima and using regular fuel results in decreased performance and at least a 10% decrease in fuel economy. It’s probably best experimenting with your specific car before proceeding.

  6. This is another tiny step in the right direction, but it's not helping 'protect the environment' in any way.

    If you went into a dark alley and someone jumped out and hit you with a baseball bat fifty times in a minute, that would be bad, right? So, if they offered you an option where they only hit you forty times in a minute, that would be 'better', right? wrong. forty beatings in a minute is *still* forty beatings in a minute. 'Less bad' is not the same thing as 'better'.

  7. This is another tiny step in the right direction, but it’s not helping ‘protect the environment’ in any way.

    If you went into a dark alley and someone jumped out and hit you with a baseball bat fifty times in a minute, that would be bad, right? So, if they offered you an option where they only hit you forty times in a minute, that would be ‘better’, right? wrong. forty beatings in a minute is *still* forty beatings in a minute. ‘Less bad’ is not the same thing as ‘better’.

  8. "Experimentation" isn't generally necessary with most newer vehicles. The auto industry is fairly clear on this: use what your manufacturer recommends. This isn't just to prevent ignorant consumers from messing with things they don't understand or to decrease potential liability. It is because in this case, those recommendations are accurate.

    Higher octane ratings don't equate to increased power. Higher octane fuel simply burns slower, making it less likely to explode spontaneously while under compression, thus causing the "knocking" or "pinging" noises you mentioned. In fact, using higher octane fuel than recommended for your vehicle can actually cause decreased performance and leave detergent deposits and carbon buildup in your engine, decreasing performance even further. And of course, this will also decrease your gas mileage. Then again, if you're looking a way to help burn through money faster (pun definitely intended), be my guest; buy the higher octane.

    The short version is this: The Car Talk folks were right. Unless your vehicle is older and you're hearing the knocking and pinging that indicate uncontrolled combustion, stick to what the manual tells you to use. If your manual isn't available, contact the manufacturer and ask them directly. They'll probably need your VIN to identify the make and model (they don't always want to take your word for it), so have it handy.

    Don't be fooled by the term "grade". In this case, it doesn't mean "better". It means "different", and has specific uses for specific vehicles. Using the grade that doesn't match your vehicle is bad for your car, bad for the environment, and bad for your wallet. :-)

    Ezra Ekman

  9. “Experimentation” isn’t generally necessary with most newer vehicles. The auto industry is fairly clear on this: use what your manufacturer recommends. This isn’t just to prevent ignorant consumers from messing with things they don’t understand or to decrease potential liability. It is because in this case, those recommendations are accurate.

    Higher octane ratings don’t equate to increased power. Higher octane fuel simply burns slower, making it less likely to explode spontaneously while under compression, thus causing the “knocking” or “pinging” noises you mentioned. In fact, using higher octane fuel than recommended for your vehicle can actually cause decreased performance and leave detergent deposits and carbon buildup in your engine, decreasing performance even further. And of course, this will also decrease your gas mileage. Then again, if you’re looking a way to help burn through money faster (pun definitely intended), be my guest; buy the higher octane.

    The short version is this: The Car Talk folks were right. Unless your vehicle is older and you’re hearing the knocking and pinging that indicate uncontrolled combustion, stick to what the manual tells you to use. If your manual isn’t available, contact the manufacturer and ask them directly. They’ll probably need your VIN to identify the make and model (they don’t always want to take your word for it), so have it handy.

    Don’t be fooled by the term “grade”. In this case, it doesn’t mean “better”. It means “different”, and has specific uses for specific vehicles. Using the grade that doesn’t match your vehicle is bad for your car, bad for the environment, and bad for your wallet. :-)

    Ezra Ekman

  10. Your post says "Oxygenation helps to reduce carbon dioxide emissions, so the EPA encouraged the use of MTBE", but is that the correct reason? The linked EPA page about MBTE, seems to say that MBTE is added primarily to reduce polution/smog (carbon monoxide, ozone, etc).

    Of course, a cleaner burning fuel is more efficient, so less carbon dioxide is output per mile driven – but that isn't why the EPA encouraged the use of MBTA. In fact, the EPA has refused to regulate carbon dioxide emissions.

    Ironically, just this week the Supreme Court ruled that the EPA must regulate carbon dioxide just like all other pollution covered by the Clear Air Act.

  11. That's all fine and dandy until you actually try it.. I read about this a few years ago. Tried it in both of our cars, and they both knocked like mad on any kind of acceleration. Screw that.

    If you want to "save money on gas and protect the environment", get a bicycle. Switching from Premium to Regular isn't even a drop in the bucket.

  12. That’s all fine and dandy until you actually try it.. I read about this a few years ago. Tried it in both of our cars, and they both knocked like mad on any kind of acceleration. Screw that.

    If you want to “save money on gas and protect the environment”, get a bicycle. Switching from Premium to Regular isn’t even a drop in the bucket.

  13. Note to self: to generate more interesting comments on a post, write about a controversial subject that you know little about.

    Thanks for the comments and corrections, folks.

    I'm going to try out regular on my car, see how it does, and report back. That will probably not happen for a week or more, though, because I work from home (an even better way to reduce pollution).

  14. Note to self: to generate more interesting comments on a post, write about a controversial subject that you know little about.

    Thanks for the comments and corrections, folks.

    I’m going to try out regular on my car, see how it does, and report back. That will probably not happen for a week or more, though, because I work from home (an even better way to reduce pollution).

  15. You fancy people with your computer controlled cars… my truck doesn't have a computer and I have to rotate the distributer to set the timing. It will burn most anything but 89 seems to be the least noisy.

    Just be careful with your trials and if there is a bad result, don't push your car. Even if totally unrelated, saying you were doing gas experiments if something happens, you don't want to get blamed!

    • You're right, niqdanger. Any car over about 15 years old may not have the computer-driven knock control.

      Yeah, if the dealer complains about the gas, they'll have to verify octane by testing it! My lips are sealed.

  16. You fancy people with your computer controlled cars… my truck doesn’t have a computer and I have to rotate the distributer to set the timing. It will burn most anything but 89 seems to be the least noisy.

    Just be careful with your trials and if there is a bad result, don’t push your car. Even if totally unrelated, saying you were doing gas experiments if something happens, you don’t want to get blamed!

    • You’re right, niqdanger. Any car over about 15 years old may not have the computer-driven knock control.

      Yeah, if the dealer complains about the gas, they’ll have to verify octane by testing it! My lips are sealed.

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  18. yess baby – i do like to get my hands on a distributer or 3. I'm kinda lovin the whole eco goth look on the new ones mind. But i have found a few of them to be a bit on the dodgy side if you know what I'm sayin bros of the west …. now you cant say I didnt warn U ??

  19. yess baby – i do like to get my hands on a distributer or 3. I’m kinda lovin the whole eco goth look on the new ones mind. But i have found a few of them to be a bit on the dodgy side if you know what I’m sayin bros of the west …. now you cant say I didnt warn U ??

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