[Kromans1]

I'm getting my first BMW soon and I was wondering, what happens to a BMW engine when you put regular gas into it?

I won't be doing this, of course, but I'm just curious.

[Wolf 335]

[Kromans1]

Originally Posted by Wolf 335

Great, should I just delete this now?

[bucketfoot]

Other than performance and possibly gas mileage suffering, nothing is likely to happen. The electronics in modern engines will adjust for the quality of fuel being used. However, I do not know if they could try to use this against you for warranty purposes.

That said, why would you bother getting a BMW if you aren't going to use the proper fuel

[lens]

Originally Posted by Kromans1

Great, should I just delete this now?

Yes

You should always use premium fuel whenever available, if by some luck that there's no premium fuel (91 oct) available, you CAN use regular gas, but you're doing harm to essentially the fuel pump, filter, etc. They'll wear considerably more, and your gas mileage will suffer.

[BMWCCA1]

My understanding is that the premium fuel offers better additive packages to keep your injectors and valves cleaner compared to regular from the same brand. That being said, bucketfoot is correct in that your car won't die from it. I tell all my customers that they don't know if they're actually getting the grade they're paying for. Who knows whether or not the tanker driver wasn't hung-over and put the wrong hose in the wrong hole? The car's knock sensors will keep the car from hurting itself but it may also retard the timing mapping and performance may decrease. Newer BMWs say right on the gas door that 91-octane is recommended but that 89 is the minimum that should be used. The newest even say BMW recommends Shell fuels, but I don't do that, either. The premium from my local Sam's Club costs less than the regular from the nearby Shell station. I've used Kroger premium for decades ever since following the tanker truck from the Shell station to the Kroger fuel outlet. Hmm

[wtwo3]

Your car will eject you from the drivers seat and run away due to the abuse. You'll also be banned from Bimmerpost forums.

[Fifthtoe]

Immediately, nothing detrimental will happen. Especially if you drive very conservative. If you drive aggressively, you will more than likely experience decreased performance. The knock sensors will usually prevent any immediate damage; but in order for a knock sensor to work, it has to first detect knocking. Over the life of the vehicle, this may accelerate wear/failure on relative engine components.

[hoki06]

Read this thread, specifically post #23.

https://www.1addicts.com/forums/show....php?t=1936120

[Theruleslawyer]

Originally Posted by bucketfoot

Other than performance and possibly gas mileage suffering, nothing is likely to happen. The electronics in modern engines will adjust for the quality of fuel being used. However, I do not know if they could try to use this against you for warranty purposes.

That said, why would you bother getting a BMW if you aren't going to use the proper fuel

Just to add, even though the car will probably run okay, I wouldn't be too hard on it until you get premium fuel back in it.

[Pheonix]

There aren't anything special about BMW (or any other car brands)! Use RECOMMENDED fuel as specified for the car.

[DocL]

You'll end up with a spun crankhub. Will you be rebadging the car also?

[KMP259]

FYI...Sam’s Club gas is a 2nd Tier fuel without the additives used in a Top tier fuel.....that is why they sell it cheap....the internal components of a engine can only take so much detonation before it begins to fail. Your knock sensor only triggers after it has already happened.....and engines with Turbo’s ...thing happen fast...for warned is for armed.

[dizz81]

In before the "If you can't afford premium gas you shouldn't be driving a BMW" comment.

[Kromans1]

Thanks all. I was just genuinely curious. I have no intention of using regular in my new BMW.

[grannyknot]

Can't believe no one has touched on this; 91-94 octane gas may get run through a finer filter, may have some extra detergents and all the rest of the sales hype.
The difference between 87 octane and 91 octane is that 91 is harder to ignite so in a high compression engine the gas won't preignite before the optimum time in the compression cycle.
That's it.
Xylene and toluene are added to make the gas less volatile, harder to ignite.
The computers in cars these days can compensate for the wrong gas being used, so if the station you are at has run out of high test you can throw in a few bucks of regular to get you to the next gas station without hurting anything.
Does 91-94 octane gas have more power, more BTUs? Nope.
Is the price of 91-94 justified? Absolutely not, the extra additives are not that expensive.

If your engine is high compression then using 91 is a good idea because that is what it is designed for.
In my opinion, it is not better, it doesn't provide more power, most of the sales hype around it is just that, sales hype, the profit margin on 91-94 must be enormous.

[kyrix1st]

Difference between 87 vs 93 AKI is around $400 per 5,000 miles (because 93 octane offers better fuel economy and power), not to mention tip top engine condition of the latter vs. clogged injectors, knocking, and all other problems that regular gas will bring.

Why would you do that to your car?

[tturedraider]

Originally Posted by bucketfoot

That said, why would you bother getting a BMW if you aren't going to use the proper fuel

Originally Posted by dizz81

In before the "If you can't afford premium gas you shouldn't be driving a BMW" comment.

Didn’t quite make it.

Originally Posted by grannyknot

The difference between 87 octane and 91 octane is that 91 is harder to ignite so in a high compression engine the gas won't preignite before the optimum time in the compression cycle.
That's it.
Xylene and toluene are added to make the gas less volatile, harder to ignite.

Ding, ding, ding. We have a winner.

[thebmw]

Originally Posted by chaungo

You should always use premium fuel whenever available, if by some luck that there's no premium fuel (91 oct) available, you CAN use regular gas, but you're doing harm to essentially the fuel pump, filter, etc. They'll wear considerably more, and your gas mileage will suffer.

Not true. There will be no damage and the world will not end with the use of regular octane gas (at least not in the US).

Premium has nothing to do with quality. It is simply an octane rating. Premium is NOT required at all. It is suggested simply to attain maximum performance and mpg, which is what was used to rate the engines. You won't see any knocking or issues with regular with the modern engines (unless you are buying gas from a low quality station). You may see slight performance issues if you are pushing the car hard or slight decrease in mpg. But the decrease amount of $ you are saving may exceed the $ you are spending on lower mpg.

[thebmw]

Originally Posted by BMWCCA1

My understanding is that the premium fuel offers better additive packages to keep your injectors and valves cleaner compared to regular from the same brand.

Not true. Premium is simply an octane rating. Top Tier gas stations are more important that the octane rating. Additives are gas station specific, not premium or octane specific.

[thebmw]

Originally Posted by hoki06

Read this thread, specifically post #23.

https://www.1addicts.com/forums/show....php?t=1936120

Spot on.

[hoki06]

Originally Posted by thebmw

Not true. Premium is simply an octane rating. Top Tier gas stations are more important that the octane rating. Additives are gas station specific, not premium or octane specific.

Premium is typically higher octane (93) AND higher treat rate of additives. Most premiums I have knowledge of use a treat rate that is 1.5-2x the maingrade treat rate.