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Add to FavoritesIs Regular Grade Gasoline Just as Good as Premium Gas for Your Car?
This question cannot be answered categorically as the definition of "your car" needs refinement. I can however, offer you a simple way to find out. Check the operating manual. The people who produced your vehicle are the most qualified to inform you of its fuel requirements. Having manufactured the engine, they would know of any special needs your car may have. If you do not have a manual you can find the information online or call the local dealer who sells and services your brand of car.
Generally speaking, any given vehicle will have a minimum octane rating for its fuel. You should not use any fuel rated lower than this minimum. Doing so can damage your engine. But because this rating is the "minimum", you can use a higher octane fuel without problems. It will however, be more expensive and give you no added benefit.
A good rule of thumb is this: The higher the performance the higher the octane requirement. High performance engines have very high compression and advanced valve and ignition timing to squeeze the maximum power out of each drop of fuel. Each time the spark plug fires, an explosion takes place that literally blows the piston down forcing the crankshaft to turn. This happens hundreds of times per second inside an engine. If a lower than required octane fuel is used the explosion spreads too quickly and presses on the piston before it is in its correct position. This can actually break the piston and leave you sitting by the side of the road. Higher octane fuels offer a more controlled burn and let the piston get into the correct position before pressing it down.
In a standard passenger car, the average engine is not tuned to the absolute edge of performance so it can handle a less controlled quicker burn without damage. The advantage of this is longevity. Many race car engines are scrapped or rebuilt after only five hundred miles! Imagine having to do that with your everyday car. Six rebuilds just to cross the United States once!
Most cars today will easily run one hundred thousand miles without engine problems. And they will do it on low octane gas. Higher octane fuels will not make them last any longer. Therefore, for overall performance and economy, it's best to use the lowest octane fuel recommended by your cars manufacturer.
Learn more about this author, James Dreamer.
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No
This is one of those "it depends" questions. Most automobiles sold today are designed to use regular (85-87) octane gasoline. These cars include "anti-knock" sensors that detect pre-ignition of the fuel in the combustion chamber during engine operation, and will retard the spark timing if pre-ignition of the fuel is detected. This sensor has been included because pre-ignition can lead to substantial and costly engine damage (cracked or broken pistons and valves), and the manufacturer does not like engine rebuilds or replacements under warranty. Often, however, these engines will perform better (more power, possibly better MPG) with higher fuel octane because the ignition timing will be closer to optimum. The owners manual is the best source for finding the recommended octane for a particular vehicle.
Cars with high performance engines or accessories may require higher octane fuel because of higher combustion chamber pressures. Engines fitted with a turbocharger or supercharger generally require higher octane fuel because of the increased induction pressures, even though the engine itself may have a low compression ratio.
There is no benefit to using a fuel with a higher octane than is necessary for your car and your style of driving. For instance, if you own a newer "economy" car, it probably runs fine on regular.If you try a higher octane fuel for a few tankfuls, you may find that you get better MPG. If so, is the increase in MPG offsetting the increase in the price of the fuel? Does the additional performance justify switching over to the higher octane? If you cannot justify the additional expense of higher octane fuel in terms of dollars saved or actual improvement in performance, there is no reason to spend the extra money.
Brands of gasoline can vary a great deal. Chevron, for instance, bases much of its advertising on the ability of it's gasolines to clean fuel systems and combustion chambers. Chevron adds detergents and lubricants to achieve these goals. Other brands may mix in these or similar additives in lesser amounts, or not any at all, as these additives are expensive and therefore increase the retail price of the gas. Other additives, such as ethanol, increase the octane of the mixed fuel, but some cars may have lower MPG running on an ethanol mix, since the ethanol has far fewer BTUs (units of energy) by volume than does gasoline. Many communities require "winter gas" or "Summer gas" that includes up to 15% ethanol, and a reduction of MPG may be noticed during times that this fuel is used. My 1996 Ford Ranger gets 21-22 MPG on 15% ethanol fuel, compared with 26-28 MPG on straight gas.
Note that additives are generally added at the refinery for a particular truckload or brand. The gasoline is usually the same for all the local retail fuel stations in a specific area, all coming from the same refinery, and additives are what differentiates the fuels. Nationwide, gasoline has to meet certain specifications in order to be sold retail, so the differences in gas between refineries will be negligible.
If you have been experiencing poor starting, rough idling, poor acceleration, knocking sounds from the engine under acceleration, or poor gas mileage, run a few tankfuls of expensive brand-name fuel through the car and see if there is an improvement. If so, it is generally OK to run cheap gas most of the time and switch over to better fuel once in a while to "clean out the pipes". If you are happy with the way your car is running, keep doing what you've been doing.
Learn more about this author, Roger Fullerton.
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