[ggalanis]

Originally Posted by AnOldBiker

Not sure where your at, but I just retired from the industry after 30+ years and that is not what anyone did that I knew.

We have blenders, but they did the blending prior to loading for delivery. Base stock gasoline is 74 octane and the chemicals added increased the octane to the ordered octane each load.

When I worked at a couple of gas stations we offered 87, 89 and 91 octane gas.
The companies actually only delivered 87 and 91 . 89 was a 50-50 mix done at the station itself. Every now and again when we ran out of 87, it meant we were also out of 89 (which almost nobody bought) and we'd essentially sell 91 at the 87 price until we got some 87 delivered.

This is perhaps not how every gas company does it, but the two I worked for here in Montreal sure did.

[330dMSXD]

Originally Posted by ggalanis

When I worked at a couple of gas stations we offered 87, 89 and 91 octane gas.
The companies actually only delivered 87 and 91 . 89 was a 50-50 mix done at the station itself. Every now and again when we ran out of 87, it meant we were also out of 89 (which almost nobody bought) and we'd essentially sell 91 at the 87 price until we got some 87 delivered.

This is perhaps not how every gas company does it, but the two I worked for here in Montreal sure did.

87, 89, 91 Octane??

In the UK I have never heard of a petrol octane level lower than 95RON the highest rating being 102RON

Octane is a hydrocarbon that is part of all fuel. Octane ratings/numbers are a measure of a fuel's ignition properties under compression. This is expressed as a reference to the same properties of a form of octane.

There are several ways in which the octane rating can be measured and/or calculated. In the UK the Research Octane Number (RON) is the most commonly used value.

Octane Rating is a measure of how the fuel burns in your engine. Too low an octane rating can cause knocking - also known as pinking, which over time can harm your engine. Knocking results when the fuel pre-ignites in the cylinder, ahead of spark plug ignition. Higher octane rated fuel controls this pre-ignition.

[dan321]

Originally Posted by 330dMSXD

87, 89, 91 Octane??

In the UK I have never heard of a petrol octane level lower than 95RON the highest rating being 102RON

The RON rating for octane is not typically used in the US. In USA it is a number that is based on both the RON and MON octane rating, so the number in the USA is lower than that in countries that use just the RON rating.

"Anti-Knock Index (AKI) or (R+M)/2
In most countries in Europe (also in Australia, Pakistan and New Zealand) the "headline" octane rating shown on the pump is the RON, but in Canada, the United States, Brazil, and some other countries, the headline number is the simple mean or average of the RON and the MON, called the Anti-Knock Index (AKI), and often written on pumps as (R+M)/2. It may also sometimes be called the Posted Octane Number (PON)."

https://en.wikipedia.org/wiki/Octane...,_MON,_and_AKI

[Black Beauty]

Originally Posted by SCA

This Shell recommendation sticker is on our week 40 M50i.

To me looks like BMW is in bed with Shell, since they are recommending one gas company over others.

[TurtleBoy]

Originally Posted by Black Beauty

To me looks like BMW is in bed with Shell, since they are recommending one gas company over others.

Shell pays them to recommend their fuel, quite common in the industry.

[jad03060]

You should consider reviewing https://www.toptiergas.com/retailers/ to select your fuel source in the USA. That organization was formed by a fairly large group of vehicle manufacturers to help avoid long-term issues in their vehicles. That list changes over time as some vendors decide they don't want to participate for whatever reason.

[Bluedog]

I always do premium (93 octane) as 91 is rarely available, but for those that say it only costs 25 cents more a gallon then 87, you must be lucky. By me, it's a dollar a gallon more on average, sometimes more than that. So, about $20 more on a complete fillup. I believe the refineries in my area basically only do 87 so they have a longer transit for 93. It's certainly hundreds of dollars more a year doing 93 for me (not just a "few bucks"), but I'm not skimping on it regardless.

[jpw172]

Originally Posted by Tenac

If you are in a situation where you only have reg 87 it won't hurt. The X5 computer will adjust timing for it. But running it long term can cause damage to the internals and specially if a knock sensor fails (I have seen this put pistons in pieces, my grandfathers caddy). Yes fuel can be tested easily to show you are not running recommended octane and warranties can be voided because of this (also read the warranty disclaimer they have one on fuel).

My question to anyone why wouldn't you run the 91 recommend???

It cannot be cost savings bc you only save "about" $5 per tank if you filled it from 0 gallons and the cost was .25 more. Say you fill out 4 times a month that is $20 a month or $240 a year at a pretty extreme calculation. I didn't buy a SAV to be cost minded or fuel efficient.

It cannot be fuel mileage bc the cars knock sensors will retard the timing meaning less efficient combustion of the fuel its self more actual wet fuel going out the exhaust.

So why would you not run it, unless you simply didn't have it available????

Agree with this. I know with my 3 Audi’s they are pretty clear if you aren’t using premium and you have any engine issues and they test the warranty is void. I personally wouldn’t risk this for the little savings you get. Also, why buy an expensive performance car to just put non-premium gas in it?

[eelnoraa]

Originally Posted by Tenac

If you are in a situation where you only have reg 87 it won't hurt. The X5 computer will adjust timing for it. But running it long term can cause damage to the internals and specially if a knock sensor fails (I have seen this put pistons in pieces, my grandfathers caddy). Yes fuel can be tested easily to show you are not running recommended octane and warranties can be voided because of this (also read the warranty disclaimer they have one on fuel).

My question to anyone why wouldn't you run the 91 recommend???

It cannot be cost savings bc you only save "about" $5 per tank if you filled it from 0 gallons and the cost was .25 more. Say you fill out 4 times a month that is $20 a month or $240 a year at a pretty extreme calculation. I didn't buy a SAV to be cost minded or fuel efficient.

It cannot be fuel mileage bc the cars knock sensors will retard the timing meaning less efficient combustion of the fuel its self more actual wet fuel going out the exhaust.

So why would you not run it, unless you simply didn't have it available????

This is absolutely not correct. You can use 87 throughout the life of 50e, and it won’t cause damage at all. It is the min requirement. 91 is recommended. Usinf 87, you just won’t get the most out of the car. At 80k car level, I agree not to skim in the fuel grade. But it is not because of engine will break. For direct inject car, no it won’t break piston. At compression stroke, there is no fuel in the cylinder, so pre-ignition destination isn’t possible even if knock sensor fail.

But then let’s be realistic, if we start to consider something fails, then knock sensor and using 87 are probably at the bottom of concern l. How about water pump fail, oil pump failure, injector fail, timing chain guide fail …. All of these can cause catastrophic engine failure. These were all at some point know BMW engine issues.

[Tenac]

Originally Posted by eelnoraa

This is absolutely not correct. You can use 87 throughout the life of 50e, and it won’t cause damage at all. It is the min requirement. 91 is recommended. Usinf 87, you just won’t get the most out of the car. At 80k car level, I agree not to skim in the fuel grade. But it is not because of engine will break. For direct inject car, no it won’t break piston. At compression stroke, there is no fuel in the cylinder, so pre-ignition destination isn’t possible even if knock sensor fail.

But then let’s be realistic, if we start to consider something fails, then knock sensor and using 87 are probably at the bottom of concern l. How about water pump fail, oil pump failure, injector fail, timing chain guide fail …. All of these can cause catastrophic engine failure. These were all at some point know BMW engine issues.

Wow old thread here, not to argue but yes poor fuel octane levels can cause internal engine parts to fail. heck just google it to see images. Not that it is a direct cause it becomes more of a indirect cause, like choking a turbo due to running too lean etc. And to your point if it says 87 and you are using it yeah should be just fine.

[eelnoraa]

Originally Posted by Tenac

Wow old thread here, not to argue but yes poor fuel octane levels can cause internal engine parts to fail. heck just google it to see images. Not that it is a direct cause it becomes more of a indirect cause, like choking a turbo due to running too lean etc. And to your point if it says 87 and you are using it yeah should be just fine.

I think it depends on how the internal part fail. There can be many reasons. Running engine too lean for too long, this typically means cylinders and pistons are running too hot (high temperature). Because fuel injecting into cylinders has cooling effects, lack of they for too long, forge Al become brittle.

When running lower octane, what usually happens is “ping”. You can hear. This is what knock sensor detects too. It is local unintended combustion in combustion stroke away from the spark. If you keep driving, sure some thing will break.

[Tenac]

Originally Posted by eelnoraa

I think it depends on how the internal part fail. There can be many reasons. Running engine too lean for too long, this typically means cylinders and pistons are running too hot (high temperature). Because fuel injecting into cylinders has cooling effects, lack of they for too long, forge Al become brittle.

When running lower octane, what usually happens is “ping”. You can hear. This is what knock sensor detects too. It is local unintended combustion in combustion stroke away from the spark. If you keep driving, sure some thing will break.

That was kinda my point, short term you are fine no problem. But when knocking occurs like you stated there are unintended combustion happening, this can cause deposits to sit on the piston cylinder wall etc. And in say with the BMW B58 with 11.0:1 (which is very high) is a recipe for disaster and if it cannot compensate for the unintended combustion. Most likely bearings tend to fail earlier than piston failure but on many turbo engines the risk is compounded by the pressures. With direct port injection I would be far more concerned with build up than major failure happening first for a daily driver.