With several fuel options to select from at the pump, you might be thinking that any of them will work in your vehicle. But some octane levels are made for specific engines. If you drive a BMW and are wondering if it's okay to put 89 octane in its tank, we can help you. We researched this make in depth so you'll know for sure what you will need to fill it up with.
A BMW will require you to use a fuel that has a minimum octane rating of 91. Putting 89 octane in this vehicle is not recommended.
Now that we know that a BMW will require an octane rating of at least 91, we'll take a look at what could happen if you use a lower-grade fuel in this vehicle. You might also be curious about what gas is best for a BMW or why German cars use premium gas. For the answers to these questions and more, read ahead in this post to see what our research has uncovered.
The consequences of using a lower octane fuel in an engine that needs premium
We know that BMW recommends using fuel with an octane rating of at least 91 every time you fill up your tank. Failing to do so regularly can have some pretty noticeable consequences. The wrong fuel grade can decrease engine performance, lagging fuel economy, and more.
Below, we've outlined what can happen if you use a fuel that has been rated 89 or under in your BMW. Pay careful attention to the pump and be sure you are only putting premium gasoline in your vehicle.
You'll get reduced fuel economy with a lower-grade fuel
When an engine is forced to work harder, it will consume more fuel. The way a BMW engine has been designed, the fuel and air combine under a higher level of compression. Without getting into the weeds on what this means, we can tell you that the fuel that flows through it needs to be harder to ignite.
If the fuel ignites too soon, as a lower octane fuel will do, the engine's pistons can misfire. This wastes a bit of fuel every time it does this.
An engine that needs high-octane fuel relies on a higher level of compression to operate correctly. Anything short of this type of fuel will only reduce the fuel economy. But there are more reasons than just poorer gas mileage to heed the recommendation of using premium fuel in your BMW.
A lower-octane fuel will not clean the engine
Premium fuel will have several detergents and other additives that will aid in cleaning the BMW's engine. A vehicle's engine is a hot and dirty place. The carbon buildup can eventually impact the engine's performance and fuel economy.
But a premium fuel will help reduce these buildups. Anything with an octane rating of 91 or higher will have what it takes to keep your engine running cleaner and more efficiently.
The power of the BMW's engine will suffer
Earlier, we mentioned that a BMW's engine operates under a higher compression system than most other vehicles. In order for the engine to run off gasoline, the gasoline must ignite so that the pistons will move. The more compression to get that spark, the more efficient and powerful the engine is.
Should you opt for a lower octane fuel for your BMW, you will create a situation where the fuel ignites earlier than intended. The lower the octane, the less compression is needed to generate that spark. If the fuel sparks too soon, the engine will not be able to accelerate as quickly.
This can be especially noticeable if you are driving up a steep hill or are carrying a full load inside the car.
You can damage the engine by not using the correct fuel grade
The fuel that ignites too soon will also damage the engine. Putting a lower grade of fuel in an engine that requires premium gasoline leads to misfires and backfires. If this happens often, there can be costly consequences.
An engine's pistons are built tough, but they have their limits. If the engine is constantly misfiring, the pistons will take the lion's share of the damage. Over time, damage to the pistons will lead to premature wear and potential warping.
Always use the grade of fuel recommended for your vehicle's engine. It will keep your car running at its greatest potential, and also saves you on costly repairs.
What gas is best for a BMW?
If you drive a BMW, you should be using a fuel that has a minimum octane rating of 91. As we mentioned earlier in this post, this premium-level fuel will ensure better performance, and higher miles per gallon, and will safeguard your engine from damage. But 91 is only one of the two options you have to decide between.
A BMW can also consume 93 octane fuel. In fact, this fuel grade will be even better for your BMW's engine. Its higher level of compression will be best for the vehicle's acceleration. The additional additives will also work to further reduce carbon and other buildup within the engine.
Though 91 octane will be fine for your BMW, experts maintain that a fuel with an octane rating of 93 is the way to go when available.
Why do German cars use premium gas?
If you've ever gone to refuel an Audi or a Mercedes, you've discovered that these makes require premium fuel. Just like BMW, these cars are manufactured in Germany. The automakers in this country make solid, reliable vehicles, nearly all of which are going to consume fuel with a minimum octane rating of 91.
The engines that German automakers use are designed for optimum performance. The quick and smooth acceleration of these vehicles means that an engine with a higher compression is needed for that expectation to be met. We know from earlier in this post that this type of compression can only be achieved if a premium fuel is used.
No matter what make of vehicle you are driving, be sure to use premium fuel if the manufacturer recommends it.
Will using premium fuel in a car that doesn't require it lead to better performance?
If the manufacturer recommends premium fuel, you need to use that fuel. We know that failing to do so will only harm the engine and lessen its performance. But that doesn't mean that using premium fuel will work magic on other engines.
While filling your tank with a higher octane fuel won't harm it, using this more expensive grade will give you no benefits unless your engine commands it. So if it's okay to use 87 octane in your tank, you're really better off filling up with it. It's less expensive, and you won't see better fuel economy or performance from a higher grade.
No matter what you are driving, consult your owner's manual to discover what fuel grade the manufacturer recommends. For best results, stick with that grade. Use the same grade consistently.
What if I accidentally use the wrong grade of fuel?
Mistakes happen, even at the gas pump. If your vehicle requires premium fuel and you accidentally fill it up with a lower-octane option, you might notice some negative effects after you hit the road. But this isn't cause for alarm.
While the fuel economy will lag and the engine might not run its best, one tank of lower-grade fuel will not ruin the engine. So you won't need to drain the tank and fuel line. Just be sure to fill it with the recommended octane level the next time you are low on fuel.
If you accidentally use diesel fuel in a non-diesel engine, that's another matter. Have your tank and fuel line drained so that the fuel will not damage the engine.
Like most cars produced in Germany, a BMW will require that you always use a minimum octane grade of 91. Though this will cost you a bit more per gallon at the pump, its engine relies on this fuel type for optimum performance. Consider an octane grade of 93 for any BMW for the best results. Drive safe!
You're at the end! We hope this post answered all of your questions. For more helpful information, we recommend reading the following posts:
My BMW Check Engine Light Is On But Gives No Message Or Codes – Why? What To Do?
Where Is The Ground Strap On A BMW? [And How Do You Replace It]?
Is Your BMW Active Grille Not Opening Or Closing? Here’s What To Do!