[thebmw]

Originally Posted by hoki06

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.

That is interesting to hear. I have not heard that. I have always thought it's gas station specific, except for maybe Amoco that used to advertise their Crystal Plus premium.

I guess the question then will be do we need twice the detergents as regular especially if it is already top tier gas. Furthermore, adding fuel treatment cleaner, which is recommended once every 3,000 miles at the cost of $10 maximum, would be far more economical than filling with premium just for the detergent difference. It usually costs at least $10 more to fill up with premium on every refill.

[hoki06]

Originally Posted by thebmw

That is interesting to hear. I have not heard that. I have always thought it's gas station specific, except for maybe Amoco that used to advertise their Crystal Plus premium.

I guess the question then will be do we need twice the detergents as regular especially if it is already top tier gas. Furthermore, adding fuel treatment cleaner, which is recommended once every 3,000 miles at the cost of $10 maximum, would be far more economical than filling with premium just for the detergent difference. It usually costs at least $10 more to fill up with premium on every refill.

Consistent use of a Top Tier gas is the most important. Premium branded fuels (Shell, Exxon, etc.) have the added benefit of very quick clean up for both IVD and GDI injectors in as little as 1 tank with today's additive technology.

My general recommendation is to use Top Tier fuel with the appropriate octane for your vehicle. If you frequent cheap, unbranded stations to save pennies then use an aftermarket additive bottle or run 1-2 tanks of Shell/Exxon premium every ~5 tanks.

[thebmw]

Originally Posted by hoki06

Consistent use of a Top Tier gas is the most important. Premium branded fuels (Shell, Exxon, etc.) have the added benefit of very quick clean up for both IVD and GDI injectors in as little as 1 tank with today's additive technology.

My general recommendation is to use Top Tier fuel with the appropriate octane for your vehicle. If you frequent cheap, unbranded stations to save pennies then use an aftermarket additive bottle or run 1-2 tanks of Shell/Exxon premium every ~5 tanks.

We're basically saying the same thing. Using top tier regular gasoline is perfectly fine for virtually any car. If it's a highly tuned car or a twin turbo, perhaps knocking may be seen with higher acceleration. I have personally never noticed any knocking on numerous high-powered cars with regular octane gasoline from a top tier provider. The key is to get quality gasoline (again, octane has nothing to do with quality). I also use various additives every few thousand miles to keep the engine in tip top, pristine shape, regardless of the octane I use.

By the way, I have no idea what the situation is in other countries. This Is US specific.

[br438]

^^ Brings to mind the question. Our COSTCO advertises on the pump that they are selling Top Tier gasoline. Does anyone have any knowledge to the contrary?

I love saving the $$ at the pump, but I can also shop at kroger and buy gas at Shell... and be close in price with the discount. It feels like the shell stations around here have a higher chance of being shady than COSTCO. ??

[Kromans1]

Originally Posted by br438

^^ Brings to mind the question. Our COSTCO advertises on the pump that they are selling Top Tier gasoline. Does anyone have any knowledge to the contrary?

I love saving the $$ at the pump, but I can also shop at kroger and buy gas at Shell... and be close in price with the discount. It feels like the shell stations around here have a higher chance of being shady than COSTCO. ??

I'm just thrilled to be able to use Costco gas again, as at my local Costco, they do not allow you to use the pump on the opposite side of your tank. With the vast majority of tanks being on the drivers' side, this creates long-ass lines with only half the pumps being utilized. I look forward to zipping past and pulling rig up to the pump on the correct side of the vehicle.

[br438]

Originally Posted by Kromans1

I'm just thrilled to be able to use Costco gas again, as at my local Costco, they do not allow you to use the pump on the opposite side of your tank. With the vast majority of tanks being on the drivers' side, this creates long-ass lines with only half the pumps being utilized. I look forward to zipping past and pulling rig up to the pump on the correct side of the vehicle.

Hahahaha...

To the OP - just use 91/93. Drive with a soft foot if the $$ hurts - these cars SIP gas for what they are.

Also - checked Top Tier's website - retailers must sell Top Tier fuel for all grades at all locations to be "certified". Costco is certified. so.. Maybe look into getting a Costco membership if you have one close. It does help

[TAZ007]

Originally Posted by Kromans1

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

At the end of the day, the owners manual and sticker inside the gas door state the minimum octane rating of 89. I suggest that be your guide to prevent breach of warranty.

[dizz81]

Originally Posted by TAZ007

At the end of the day, the owners manual and sticker inside the gas door state the minimum octane rating of 89. I suggest that be your guide to prevent breach of warranty.

Wait is this in non M BMW's? I'm just curious but my M definitely says min 91.

[TAZ007]

Originally Posted by dizz81

Wait is this in non M BMW's? I'm just curious but my M definitely says min 91.

I cannot speak to the true "M"'s as I have the G29 M40. I will say the next time you stop at the pump, take a look at the sticker for the minimum octane rating. That is your guide. I will say the comparison I observed from 89 v 93, is not appreciable in normal everyday driving.

[thebmw]

Originally Posted by br438

^^ Brings to mind the question. Our COSTCO advertises on the pump that they are selling Top Tier gasoline. Does anyone have any knowledge to the contrary?

I love saving the $$ at the pump, but I can also shop at kroger and buy gas at Shell... and be close in price with the discount. It feels like the shell stations around here have a higher chance of being shady than COSTCO. ??

Costco gas is top tier. Been using it for years. Vary between regular and premium depend on the car and my planned use of that car and the price. Sometimes there is a differential of 10%. Sometimes the differential is 35%, which doesn't make sense from a mpg standpoint.

Some may say it's only a few hundred dollars at the end of the year. They would be correct. But if you have a few hundred dollars that you don't care about, I have a zelle/paypal account you can send it to .

If you stick with top tier like Costco and you fill up regular and you are not tracking your car, you will be just fine. No engine damage, no harmful contaminants, etc.

[thebmw]

Originally Posted by TAZ007

I will say the comparison I observed from 89 v 93, is not appreciable in normal everyday driving.

Bingo. I have noticed at time, in certain weather, that their is a 1mpg difference, which amounts to about 4% difference. So if premium costs 4% more than regular, you are burning money (again, assuming top tier gas).

[kyrix1st]

Knocking has to happen first for the knock sensors to detect and stop the car from doing so. Such repetition will eventually score your pistons and the cylinder. Regular will cause knock for most 6 cylinders and up. You also have to keep rpm & load down on regular, which causes more frustration. There's a reason why minimum AKI is stated as "emergency only" grade and should not be driven over a certain speed (i.e. engine load) or engine speed.

For us M owners, few hundred difference isn't big enough to risk expensive engine and fuel system related failure. The car just runs so much more efficient on 93 AKI.

Originally Posted by thebmw

Costco gas is top tier. Been using it for years. Vary between regular and premium depend on the car and my planned use of that car and the price. Sometimes there is a differential of 10%. Sometimes the differential is 35%, which doesn't make sense from a mpg standpoint.

Some may say it's only a few hundred dollars at the end of the year. They would be correct. But if you have a few hundred dollars that you don't care about, I have a zelle/paypal account you can send it to .

If you stick with top tier like Costco and you fill up regular and you are not tracking your car, you will be just fine. No engine damage, no harmful contaminants, etc.

[SubmarineSonar]

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

I don’t think the OP was going to use low-octane gas. he was just wondering what would happen and why. It's a reasonable question.

[thebmw]

Originally Posted by kyrix1st

Knocking has to happen first for the knock sensors to detect and stop the car from doing so. Such repetition will eventually score your pistons and the cylinder. Regular will cause knock for most 6 cylinders and up. You also have to keep rpm & load down on regular, which causes more frustration. There's a reason why minimum AKI is stated as "emergency only" grade and should not be driven over a certain speed (i.e. engine load) or engine speed.

For us M owners, few hundred difference isn't big enough to risk expensive engine and fuel system related failure. The car just runs so much more efficient on 93 AKI.

Chance of knocking is higher with engines that require greater explosive power...usually higher compression engines or those that have been tuned, forced induction, etc. This is not a "M" car issue vs. non-M car issue. In fact, many non-M cars have higher demands than M cars. In either case, for a long time, I have not seen knocking in ordinary driving with stock cars and regular gas from top tier providers (M cars, non M cars, BMWs, non-BMWs). I've never seen engine failure due to octane either (again, not talking about a highly tuned car that is being raced).

I don't know what the gas situation in Japan so your results may be quite different than mine.

[SteveinArizona]

Originally Posted by 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.

I only use top tier gas but how do you know that Sam's Club gas is second tier? Maybe Walmart just didn't want to spend the bucks (it is a starving company) to be qualified. Or maybe it is truly crappy gas. Not a risk I want to take. I generally either use Costco or Shell 91 gas (we don't get 93 out here).

[StanDiego]

Originally Posted by 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.

You're going to be getting many types of responses to this, some of it misinformation. Seeing that you're in the US, I'll share what applies in the US. I'm unfamiliar with other countries fuel regulations.

Many believe premium fuel has more or better additives than regular. NOT TRUE! There may be some rare exceptions for boutique premium blends but regulations ensure all fuel sold in the US has a minimum amount of additives. In most cases regular gas has the same amount as premium in a particular brand. Another specification (not regulation) is "Top Tier". "The additive companies create additive formulations and conduct testing, ultimately receiving TOP TIER™ approval.

The fuel retailer licensee agrees to purchase fuel treated with a TOP TIER™ additive at the correct concentration and display the logo." Read more at https://toptiergas.com/.

Most major vehicle manufacturers recommend (but don't require) Top Tier fuel.

So… if most fuel brands include the same additives in all of their fuel, what is the difference between regular, mid grade, and premium? OCTANE

Contrary to popular belief, premium is not more powerful than regular gas. Premium is formulated to reduce pre combustion ((when the fuel combusts before it's supposed to (it's suppose to combust when the spark plug fires)). The octane number is the measurement of the fuel's tendency to precombust. The lower the number, the easier it is to combust (at lower temperatures and/or compression levels).

Recommended octane levels vary by vehicle. On my G29 Z4, minimum is 89 and recommended is 91. What happens if I use regular (87 octane)? I'm likely to get more precombustion (synonymous with preignition), especially at higher temperatures and under greater load (accelerating or going uphill for example). Over time, excessive pre combustion can cause damage and/or premature wear to the engine components (precombustion generates forces against the piston before it's reached the top of its stroke), decreasing engine longevity.

Most or all modern vehicles have technology that can identify precombustion. They differ in how well they handle it. Many will adjust the ignition timing (and perhaps air/fuel ratios) to effectively compensate, resulting in reduced engine performance but minimizing any damage to the engine. Some vehicles don't manage it as well as others. I can't tell you specifically how BMW vehicles manage it because it's proprietary information.

Bottom line: Try to use the minimum octane recommended by the manufacturer (in the manual and near your gas cap). If on rare occasion you only have access to regular 87 octane gas, it'll be perfectly fine to use it as long as you don't put the engine under heavy load (high temperatures, towing, long uphill climbs, etc.) Fill it up with the recommended octane at the next opportunity.

[Kromans1]

Originally Posted by StanDiego

You're going to be getting many types of responses to this, some of it misinformation. Seeing that you're in the US, I'll share what applies in the US. I'm unfamiliar with other countries fuel regulations.

Many believe premium fuel has more or better additives than regular. NOT TRUE! There may be some rare exceptions for boutique premium blends but regulations ensure all fuel sold in the US has a minimum amount of additives. In most cases regular gas has the same amount as premium in a particular brand. Another specification (not regulation) is "Top Tier". "The additive companies create additive formulations and conduct testing, ultimately receiving TOP TIER™ approval.

The fuel retailer licensee agrees to purchase fuel treated with a TOP TIER™ additive at the correct concentration and display the logo." Read more at https://toptiergas.com/.

Most major vehicle manufacturers recommend (but don't require) Top Tier fuel.

So… if most fuel brands include the same additives in all of their fuel, what is the difference between regular, mid grade, and premium? OCTANE

Contrary to popular belief, premium is not more powerful than regular gas. Premium is formulated to reduce pre combustion ((when the fuel combusts before it's supposed to (it's suppose to combust when the spark plug fires)). The octane number is the measurement of the fuel's tendency to precombust. The lower the number, the easier it is to combust (at lower temperatures and/or compression levels).

Recommended octane levels vary by vehicle. On my G29 Z4, minimum is 89 and recommended is 91. [...]

A fantastic explanation. Thank you very much!

[hoki06]

Originally Posted by StanDiego

....Many believe premium fuel has more or better additives than regular. NOT TRUE! There may be some rare exceptions for boutique premium blends but regulations ensure all fuel sold in the US has a minimum amount of additives. In most cases regular gas has the same amount as premium in a particular brand....

I wasn't going to respond in this thread again, this topic was recently covered at length in the thread I previously linked, but I couldn't let this one go. The above quoted comment is false and in fact the exact opposite is true especially for branded fuels. Premium fuel is at minimum higher octane and more often than not has a higher additive treat rate. This is particularly true for branded fuel stations (Shell, Exxon, BP, etc.) where the maingrade 87 octane is a Top Tier treat rate and the premium 93 octane is 1.5x or 2x the Top Tier treat rate. Unbranded fuels (7-11, Wawa, etc.) might use the same LAC treat rate in their premium fuels, my direct knowledge is focused on branded fuels.

[StanDiego]

Originally Posted by hoki06

The above quoted comment is false and in fact the exact opposite is true especially for branded fuels. Premium fuel is at minimum higher octane and more often than not has a higher additive treat rate. This is particularly true for branded fuel stations (Shell, Exxon, BP, etc.) where the maingrade 87 octane is a Top Tier treat rate and the premium 93 octane is 1.5x or 2x the Top Tier treat rate.

I haven't done exhaustive research but casual research (fuel manufacturer websites) suggests otherwise, somewhat in between what the two of us have stated. It does appear that more brand name fuels put higher levels of additives in premium these days (Shell, BP) but others (Texaco, ARCO) claim no such thing (that I've been able to find).
COSTCO claims "Kirkland Signature™ Gasoline contains five times the EPA detergent requirement in both regular unleaded and premium grades".

Summary: I have always recommended Top Tier gasoline as do most vehicle manufacturers and industry experts. However, I am unable to find a single industry expert (other than perhaps the fuel manufacturers themselves) who recommends using a higher octane gasoline than what is recommended by the vehicle manufacturer. The vast majority of industry experts claim it is a waste of money to do so and I agree.

[TheMaxXHD]

Throwing my ring in the hat here. I love the discussion. With that said, this discussion is somewhat useless. While we can debate whether or not it is worth it or not to use a higher or lower octane rating than a low amount from a purely technical perspective, it may not matter.

I agree with whoever said to always put atleast the minimum listed in, if for nothing else due to potential warranty implications. I don’t think anyone can prove or disprove with 100% certainty what BMW will do if there is an issue with say the engine or anything fuel related and they see a lower octane rating than the minimum stated in the vehicle. Likely, they wouldn’t care or notice, but if they do, well?

In addition, where I live in the US, often times (Wawa, Sheetz, and Sunoco to name a few) don’t have a 91 rating. Instead they jump from 89 straight to 92 or 93 octane as the highest. In which case, on my 2011 328i 6 cyl, the minimum per the gas port is 91. Could it do 89? I’m sure I can, do I want to chance it on an expensive vehicle?

While I often just put whatever the highest is in to be safe, that is not what you have to do. With that said, I trust BMW’s rationale for putting minimum 91 on the car as opposed to this thread. There must be a reason, even if its only for a few extra performance ticks and 1 MPG.

At the end of the day, these vehicles are not cheap. New or old, BMW parts aren’t cheap. You know that going into buying it. These are cars you have to maintain well, and are expensive when you do, and even more expensive when you neglect them. If you can’t afford higher ratings of octane, you have the wrong car, because you definately won’t be able to afford the BMW parts you eventually will need simply through wear and tear.

You want a gas economical car, you are buying the wrong brand. BMW is fuel efficient, but there are even better options out there. Nothing wrong with that, but if fuel efficiency and maximum car savings is your objective, you should be worrying less about octane and more about the vehicle you have.

My personal opinion, on how expensive these cars are, why risk even any damage at all from a lower octane rating than minimum? Minimizing damage with modern sensors is not the same thing as preventing damage. It could still wear the engine down, especially over time.

TLDR; Just put atleast the minimum in iit says to, ideally recommended if it says. If you don’t like that, don’t buy the car and buy another car that doesn’t say that. There are plenty of great cars out there. I’m sure you can find something you like that has a lower minimum rating.

[hoki06]

Originally Posted by StanDiego

I haven't done exhaustive research but casual research (fuel manufacturer websites) suggests otherwise, somewhat in between what the two of us have stated. It does appear that more brand name fuels put higher levels of additives in premium these days (Shell, BP) but others (Texaco, ARCO) claim no such thing (that I've been able to find).
COSTCO claims "Kirkland Signature™ Gasoline contains five times the EPA detergent requirement in both regular unleaded and premium grades".

Summary: I have always recommended Top Tier gasoline as do most vehicle manufacturers and industry experts. However, I am unable to find a single industry expert (other than perhaps the fuel manufacturers themselves) who recommends using a higher octane gasoline than what is recommended by the vehicle manufacturer. The vast majority of industry experts claim it is a waste of money to do so and I agree.

I work for an additive company in our fuels division so I have direct knowledge of additive technology, performance, and treat rates for many fuel companies. Whenever this topic comes up I try to carefully comment to share my knowledge and teach others without giving away specifics that would be frowned upon.

Using a higher octane rating than recommended is a waste of money, yes. This is very well known. Engine controls are so sophisticated these days that they will adjust to preserve the engine despite whatever fuel you put in, to a degree. Some manufacturers now even give power ratings based on fuel octane used, see the new Ford Bronco 2.3L and 2.7L specs.

My comments are mostly around additives and their treat rates. I'm constantly amazed at how people have strong opinions with little to no actual knowledge or data. Additives are not snake oil, there is an entire industry for fuel additives and the EPA has a minimum amount required because they work to reduce deposits. Additives do make a significant difference in performance and there are millions of dollars spent by many companies to generate data to support their marketing claims.

[BMWCCA1]

So how do you convert octane recommendations on your gas flap to the formula for octane ratings on the pump? Aren't they totally different systems of measurement/equations?

“There are two measurements: research octane (RON), and motor octane (MON). The octane rating that you see on the pump is an average of these two different ratings. The measurements are made on specially designed ‘knock’ engines to determine the ratings.”

The good news is that at its most basic level, regular gas is regular gas, and 91 RON in Germany is equivalent to 87 AKI in the United States. Premium is the same, and while premium gasoline is often called “super” by some retailers, 95 RON in Germany is equivalent to 91 AKI in the USA and Canada.

So is AKI (Anti-Knock Index) on your flap the same as the RON+MON/2 on the pump?