Is using a better grade (and more expensive) gasoline worth it in the long run as it increases fuel economy?

Answer 1

I recommend reading the US Federal Trade Commission's Facts for Consumers - "The Low-Down on High Octane Gasoline"
http://www.ftc.gov/bcp/edu/pubs/consumer/autos/aut12.shtm

You should use whatever the owner's manual recommends.

If your car is experiencing engine knock, then you should go up a grade in octane. (But if your car IS knocking, something may be wrong with it and it may need a tune-up!)

Octane is a measure of the fuel's ability to resist pre-detonation (or engine knock).

Higher octane gasoline doesn't mean that it is necessarily cleaner or better. "Premium" is a mis-nomer. All gasoline sold in the US must meet certain federal EPA clean-burning guidelines. However, some individual brands _may_ decide to put some extra cleaners or extra refining in their higher-octane fuel (as I've heard of some brands advertising low-sulfur gasoline as only in their Premium line).

A higher octane gasoline actually has lower BTUs (energy content) than a lower octane gasoline, so the only way that you'd see better fuel economy by going up in octane is if you were previously using lower than recommended octane in your car...

For an occasional tank, you could get away with using a lower octane than recommended in a car that requires "premium" fuel, as the car will adjust, but it can cause some extra wear on the engine while knocking.

If you live in a high altitude area (like the Rocky Mountains) usually you can use the next octane level down from what is listed in the owner's manual because of the altitude/thin air with no ill effects (except if you come down from the altitude with a full tank!).

For some cars, such as the Toyota Prius, using higher than the recommended octane fuel is known to cause check engine lights with engine misfire codes (because of the Atkinson cycle engine, rather than the Otto cycle engine most other cars use) due to the late detonation, besides the expected lower fuel economy.

Reasons to use higher octane fuel:
1. Your owners manual calls for it
2. Your engine is knocking
3. It's the only way to get low-sulfur fuel in your area (sulfur will slowly poison your catalyst, making emissions worse over time)
4. You like spending extra money on gasoline


See also:
Premium vs. Regular : http://cartalk.com/content/features/premium/

Answer 2

It would if it increased fuel mileage. But in reality higher grades of gas have less available energy than standard unleaded. So, I don't think you will see it happen. Higher grades are used mostly on engines requiring it to prevent pinging. Years ago you could get the benifits of high test by adding about two shots of transmission fluid to a tank of gas. Wouldn't suggest that on newer cars though. Worked well on pre 80's.

Answer 3

You would have to find studies done on the particular make of vehicle-higher octane rating doesn't guarantee higher fuel efficiency. Then you would have to compare measured performance improvement to increase in price to determine if the costlier fuel would be worth it.
Your best bet is to use the fuel the manufacturer recommends for your vehicle, which is usually only at least 87 octane.

Answer 4

The higher grade of fuel is designed for a specific type of high performance engine. If your vehicle is standard the higher octane fuel can be a waste of money and also cause your spark plugs to overheat & interfere with the proper carburration of your engine. Read your vehicles service manual for the correct fuel for your vehicle,(and the correct spark plugs, if you don't have fuel injection ).

Answer 5

It is only better if you have a high performance vehicle. Normal cars work fine on the lower grade and there will not be any difference in fuel economy.

Answer 6

Recently I read that even if your car manual suggests Premium gas,it may also state that you can use regular grade & for economy it's supposed to really improve your spending in the long run...(that last part didn't come from the manual)

Answer 7

No. The earlier answerers are correct in saying that unless your car is designed for premium gas you're wasting your money. In addition, because it takes more oil and energy to refine higher-octane fuel while your mileage remains virtually identical, it's also worse for the environment.

Answer 8

No. Newer cars are designed or certain fuels. Check the owners manual. Otherwise you are wasting your money, and could actually cause a loss of performance.

Answer 9

coincidentally, i experienced a comparison. we always used high grade fuel in our vehicles which were, usually a g m product. why?....go figure. there was a time when we couldn't get premium at the pump. the performance of the engine was very noticeable. it sounded awful too.

to answer your question, yes, it is worth every penny you spend in the long run.