If I don't put premium (93 octane) gas in my 2005 BMW 530i, will it damage my engine if 89 or 91 octane used?

Answer 1

well, there are several things that you have to understand, you have a high performance engine, the higher octane is needed because it is more violatile, it burns hotter, faster and more explosively. you probably have a higher compression ratio in the engine, so it needs the higher octane to burn cleaner, you will notice a pinging, hesitation, and fuel economy will suffer, this is why most high performance cars of the 60's and 70's need to run on racing fuel, I know of a 62 Mopar 413 engine that has a head splitting 13.5:1 compression ratio, and would not even run on 93, it would need at least 105 octane. So, generally speaking, it is acceptable to use the 91, but it is not recommended, but to make it better, use the 91 but add fuel octane boost to it, generally it says 1 bottle for up to 20 gallons will raise the octane 1 point, there is one called 101 octane that raises it i think 5, but it is like 6 bucks a bottle if i remember right. hope this helps

Answer 2

Yes it can... The octane rating of fuel directly determines the speed of the "flame front" in the cylinder when the spark plug fires. The higher the octane the slower the fuel will burn. If regular gas is burned the mixture explodes and expands quickly, often before the piston reaches the top of the cylinder. This causes knocking or pinging which can damage the engine. Use the grade reccomended by the manufacturer. By the way, putting premium gas in a car designed for regular will not give you more power, it will often give you less - but it won't hurt the engine.

Answer 3

It MAY damage the engine in the long run but u can minimize the risk by using fuel additives that clean the engine after every few thousand miles. If u don't plan on keepin the car forever (i.e. more than 5 yrs) just go with the cheap stuff and save...

Answer 4

You best follow maufatures recommendation. Octane ratings are not for how "clean" or how fast the fuel burns, its for its ability to resist detonation (pinging). Detonation is the death rattle of any engine. To keep your warranty good put in the correct gas.

Answer 5

The general rule is the more you're going to load your car with weight the higher the octane should be. Your BMW is pretty sharp and fast, if you're going to race it with low octane you might hurt the engine...

Answer 6

It won't hurt it. The computer will automatically adjust the timing to compensate if it detects pinging. But you'll have a performance loss and increased emission.
So, use it if you can't find the right stuff in the middle of nowhere, but use what the book says the rest of the time.

Answer 7

i don't think that a big difference between 93 and 91 all will work normally

Answer 8

Looks like Mr Z called it right!

Answer 9

Go by whatever the owner's manual says, otherwise you might cause damage. But I just say MIGHT.