If a car calls for premium fuel, will putting regular unleaded cause harm?


I’ve heard that unless you are driving a high performance vehicle such as a Porsche or Ferrari, then it doesn’t really matter.

Simply consult your owners manual and find out what the minimal octane rating for your car is. Then, at the gas station, fill up with gas at or above this point. Many VW/Audi cars say something along the lines of “premium gasoline only, etc,” however, if you consult the manual, it states that the minimum octane needed is 87, which, coincidentally, is regular fuel. Regular is suitable for nearly all current vehicles by major manufacturers. Also bear in mind that at higher altitudes it is wise to fill with a grade one step higher than you normally would.

Putting in lower grade fuel than recommended, WITHIN REASON, will not immediately cause harm. However it will accelerate wear over time in certain parts of the engine, possibly lead to random misfires, and most importantly, you will lose so much MPG that it would actually be a better economical move to pay for the better gas. However, in an emergency (e. g. when youre running on empty on a highway in Mexico and all they’ve got is 84, it would be fine. Doing this once in a while is fine, but frequently is not a good idea at all.

It might. The more expensive fuel is designed to prevent knocking, so you might experience that for a while. Cars are pretty good these days at adjusting, so it probably wouldn’t last too long. You might lose some performance or even mpg during that time though. It’s also possible it wouldn’t ever improve.
But even fuel manufactures say that in most cases you are fine to use the lower octane gas, and many people do.

On the other hand, it really doesn’t add up to that much more money to use the better stuff, depending on your driving of course.

I would just try it (if you are talking about your car) and see what happens. I haven’t read anything about it actually causing harm to a vehicle, nothing that doesn’t go back to normal by switching back to premium.
Everytime the price of fuel jumps up there are tons of articles about people who use regular instead of premium, some say they switched back to the premium, and others say they didn’t notice any difference. I guess it all just depends.

It can cause engine retard or knock from the timing if you use the wrong octane for your car. I would use what the company recommends. My car calls for premium and I always use it and she is not what you would consider a high performance car. She has a supercharger and I have done some mods to her so I make sure I use the highest octane that I can to ensure everything runs good. It’s not that much more expensive anyway. Generally only about 15-20 cents, and when you’re already paying probably at least $50 to fill up, whats another 2 or 3 bucks to make sure your car stays running good?

Harm? no

But It’s not good and can possibly void your warranty.

My car recommends premium. If I use regular the knock sensors detect it and will retard the timing to accommodate… but it’s still not advised.

Some cars will only take regular in the same way… We used to have a VW van that if you put premium in it, it would screw it up and it wouldn’t run right.

Stick with what it tells you do.. they aren’t trying to get more money for the gas companies, they are trying to do what is best for you car.

If you don’t like the price… don’t pay attention to it. That’s what I do, I just go by the regular price, stick the nozzle in and hit premium, it’s not that much of a difference. If it keeps your car in good shape, the extra $2 is worth it.

Premium fuel has a higher octane (89, 92, etc) level than regular fuel. This means that you can run at higher compression ratios without pinging when using higher octane. Lower CR = lower power and fuel economy from a mechanical point of view. Furthermore, with modern computer controlled engines, timing will be retarded (limp home mode) and you will lose even more power/MPG this way. Read your manual to determine warranty effects of using regular.

To me, it does not make financial sense to save a few bucks on a tank of gas yet get worse MPG and possibly cause other problems.

If the manufacturer calls for premium gas for your engine, there is a very real chance of doing damage to your engine if you regularly use a lower octane.

Premium gas is usually categorized as such because of its high detergent content. This means that this gas will, by its nature, clean out and prevent deposits in your engine while it is being used. With these deposits gone, the engine will use the gas more efficiently and it will also be able to use oxygen more efficiently in the combustion process. Thus, fuel is conserved and power is increased by using these premium fuels.

Regular grade gas has much lower detergent levels, which is why it is so much cheaper. It has the same fuel-potential (or energy) as premium gas, but it is more likely to leave deposits behind in the engine, thus slowly degrading the efficiency and power of the engine.

You heard wrong.

If car calls for premium fuel, it’s because the engine is calibrated for it. It doesn’t matter if the car’s hi-perf or not.

Use of lower octane fuel will cause the engine to go into “limp mode”, retarding the engine firing to produce less power and torque. If this persists for a long time, it may do damage to catalytic converter and/or oxygen sensors.

It wont necessarily cause harm…I put regular in my car once (it takes premium) and it drove sluggishly and strange…it would sputter and jerk…I wouldnt recomend it at all

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