Regular gas in my S63

[Bmwtechgeek]

Soooo wife accidentally filled up my tank with regular 87 octane. After yelling at her for 30 minutes, cooler heads prevailed.

Is my engine doomed?

[NorthCountryGuy]

No.
Drive it out.
You’ll be fine.
It’s not like it was diesel.

[Qsilver7]

What is the minimum AKI requirement for the s63? This should be in your owners manual or on a sticker near or around your fuel filler flap.

If it is 89 AKI...then when you get to half a tank...put the highest AKI in your area (91 or 98 AKI...this will bring the fuel left in the tank up to the minimum (if the minimum is 89 AKI).

Your owners manual also should tell you what happens when you use fuel below the “recommended” fuel spec (lower performance & higher gas consumption).

Your engine also has knock sensors that help when low grade fuel or incorrect octane is used. Here’s some info from the TIS about the knock sensors...you can also go to the site, enter the last 7 digits of your VIN...then type knock control into the search box for even more info: https://www.newtis.info/tisv2/a/en/f...ensor/6LPkwe8E

[Bmwtechgeek]

Originally Posted by Qsilver7

What is the minimum AKI requirement for the s63? This should be in your owners manual or on a sticker near or around your fuel filler flap.

If it is 89 AKI...then when you get to half a tank...put the highest AKI in your area (91 or 98 AKI...this will bring the fuel left in the tank up to the minimum (if the minimum is 89 AKI).

Your owners manual also should tell you what happens when you use fuel below the "recommended" fuel spec (lower performance & higher gas consumption).

Your engine also has knock sensors that help when low grade fuel or incorrect octane is used. Here's some info from the TIS about the knock sensors...you can also go to the site, enter the last 7 digits of your VIN...then type knock control into the search box for even more info: https://www.newtis.info/tisv2/a/en/f...ensor/6LPkwe8E

Minimum is 91. It says it right on the gas cap.

I plan to drive it very gingerly until half tank and then top it off with some 94 which I can get locally.

Very informative info on the knock sensors. Thanks you are a blessing to this forum.

[thebmw]

Absolutely no issue. Octane has NOTHING to do with quality. It simply refers to the combustiblity, which affects knock. Fill the cheaper gas to your heart's content and save some money. Might see lower mpg and power though.

[Flying Ace]

You'll be fine. If you're so concerned, at about 1/2 of the tank, top off at 93 premium and you essentially have balanced it out to an equivalent of 91 octane. This is how they make 89 mid-grade anyways, 1/4 93 and 3/4 87.


You marriage on that other hand, probably over now. Expect her to bring up counseling all of a sudden in the middle of the night when you're trying to fall asleep. Don't ask me how I know.

[Bmwtechgeek]

Thanks guys

[CrashDummy]

The whole point of a higher octane gasoline is for the gas to burn slower, resulting in less knock in higher compression engines.

M6's definitely have high compression engines, so the effect of 87 octane gas in the tank is that you may get more pre- or post-detonation, or engine knock.

The cure is to drive nicely until you burn off the cheap stuff. It's not a disaster, just don't push the engine really hard until you've burned through this tank.

[Bmwtechgeek]

Originally Posted by CrashDummy

The whole point of a higher octane gasoline is for the gas to burn slower, resulting in less knock in higher compression engines.

M6's definitely have high compression engines, so the effect of 87 octane gas in the tank is that you may get more pre- or post-detonation, or engine knock.

The cure is to drive nicely until you burn off the cheap stuff. It's not a disaster, just don't push the engine really hard until you've burned through this tank.

Yea that was the plan. This is super stressful indeed!

Thanks again

[AlpineKing]

Originally Posted by CrashDummy

The whole point of a higher octane gasoline is for the gas to burn slower, resulting in less knock in higher compression engines.

M6's definitely have high compression engines, so the effect of 87 octane gas in the tank is that you may get more pre- or post-detonation, or engine knock.

The cure is to drive nicely until you burn off the cheap stuff. It's not a disaster, just don't push the engine really hard until you've burned through this tank.

Originally Posted by CrashDummy

The whole point of a higher octane gasoline is for the gas to burn slower, resulting in less knock in higher compression engines.

M6's definitely have high compression engines, so the effect of 87 octane gas in the tank is that you may get more pre- or post-detonation, or engine knock.

The cure is to drive nicely until you burn off the cheap stuff. It's not a disaster, just don't push the engine really hard until you've burned through this tank.

Are octane booster products useful in this situation or not worth it? I've always had my doubts on their actual ability

[brad850csi]

I agree with everyone else, just drive it slowly for a bit.

Note that is isn't so much engine rpm but more boost that will create knock. These engines make boost at about 2000rpm so I'd perhaps keep the sport gauges up on the screen and try to keep it below about half of the maximum torque so you know you aren't coming on boost.

[thebmw]

S63 compression is no higher than virtually all other BMW engines. Not sure what the panic is from everyone. I put 87 octane in these so-called high compression engines all the time for years with absolutely zero knock. I've driven engines with higher compression ratios than the S63 with zero knock. These are not engines made 30 years ago. So calm down, everything will be fine even if you wanted to use 87 octane from here on out.

[arucano]

You will not hear a knock in modern engines. The engine management system will retard the ignition whenever the knock detectors detect knocking, which is long before you can hear it. The net result is you loose power.

[Bmwtechgeek]

Originally Posted by thebmw

S63 compression is no higher than virtually all other BMW engines. Not sure what the panic is from everyone. I put 87 octane in these so-called high compression engines all the time for years with absolutely zero knock. I've driven engines with higher compression ratios than the S63 with zero knock. These are not engines made 30 years ago. So calm down, everything will be fine even if you wanted to use 87 octane from here on out.

Yea I think you're right. As long as your not pushing the car hard like on a race track I think it will be ok.

Today's gasoline is good stuff even if the octane rating is lower.

[thebmw]

Originally Posted by Bmwtechgeek

Yea I think you're right. As long as your not pushing the car hard like on a race track I think it will be ok.

Today's gasoline is good stuff even if the octane rating is lower.

Correct. And I'd wager to guess it 99% of M6 owners never track their M6, especially in winter! You will notice a decrease in power and a decrease in miles per gallon. But so what if you notice a decrease in power from 575 horsepower to 550 horsepower and lose 5% fuel economy.

93 octane is typically 25% more costly. So is it worth spending 25% more to get 5% more fuel economy and to get increased horsepower that you will absolutely never use on the road? Your choice. But bottom line is your car will not be harmed with 87 octane.

[Bmwtechgeek]

Originally Posted by thebmw

Correct. And I'd wager to guess it 99% of M6 owners never track their M6, especially in winter! You will notice a decrease in power and a decrease in miles per gallon. But so what if you notice a decrease in power from 575 horsepower to 550 horsepower and lose 5% fuel economy.

93 octane is typically 25% more costly. So is it worth spending 25% more to get 5% more fuel economy and to get increased horsepower that you will absolutely never use on the road? Your choice. But bottom line is your car will not be harmed with 87 octane.

Yea I dont track and don't push the car that hard. Too many cops in my neighbourhood and I enjoy cheap car insurance.

Just worried about the well being and longevity of my S63. I'm out of warranty and not a believer in extended warranties so I just need to be on the cautious side.

[NorthCountryGuy]

Originally Posted by arucano

You will not hear a knock in modern engines. The engine management system will retard the ignition whenever the knock detectors detect knocking, which is long before you can hear it. The net result is you loose power.

Exactly.

[NorthCountryGuy]

Originally Posted by Bmwtechgeek

...I'm out of warranty and not a believer in extended warranties so I just need to be on the cautious side.

You should be.
My Son’s 750Li xDrive just clicked 120k miles. Developed a clicking sound on right hand turns. Shortly after xDrive failure - rear wheel drive only.
Tie rod/control arm failure killed the front transfer case. My warranty covered it all. The transfer case was a 5000.00 part. I just paid 300 deductible for 8+k for the total job. Allowed me to turn the car over. Even got a refund for unused portion of the warranty.

[Bmwtechgeek]

Originally Posted by NorthCountryGuy

You should be.
My Son’s 750Li xDrive just clicked 120k miles. Developed a clicking sound on right hand turns. Shortly after xDrive failure - rear wheel drive only.
Tie rod/control arm failure killed the front transfer case. My warranty covered it all. The transfer case was a 5000.00 part. I just paid 300 deductible for 8+k for the total job. Allowed me to turn the car over. Even got a refund for unused portion of the warranty.

I have a 2016 750Li as well and its been perfect. Also out of warranty. Has about 20 000km I don't drive them a lot fingers crossed.

Warranties are a scam!

[EnVe46]

Originally Posted by thebmw

Correct. And I'd wager to guess it 99% of M6 owners never track their M6, especially in winter! You will notice a decrease in power and a decrease in miles per gallon. But so what if you notice a decrease in power from 575 horsepower to 550 horsepower and lose 5% fuel economy.

93 octane is typically 25% more costly. So is it worth spending 25% more to get 5% more fuel economy and to get increased horsepower that you will absolutely never use on the road? Your choice. But bottom line is your car will not be harmed with 87 octane.

I don't agree with this, at all. The car requires a minimum octane level for a reason. Sure, one fill up isn't going to destroy it, especially if you drive it lightly. But continual use of subpar octane on a turbocharged engine is going to cause issues of some sort. Reduced performance might be the only issue but why buy a 500+ hp car to use fuel for a civic that'll reduce performance?!? If you can justify using proper fuel, go buy a 528 or something else that doesn't require higher octane.

[thebmw]

Originally Posted by EnVe46

I don't agree with this, at all. The car requires a minimum octane level for a reason. Sure, one fill up isn't going to destroy it, especially if you drive it lightly. But continual use of subpar octane on a turbocharged engine is going to cause issues of some sort. Reduced performance might be the only issue but why buy a 500+ hp car to use fuel for a civic that'll reduce performance?!? If you can justify using proper fuel, go buy a 528 or something else that doesn't require higher octane.

You are implying that lower octane will "detroy" an engine but then you say it will just reduce performance. Do you know what octane is? It has NOTHING to do with the quality of the fuel. So you can agree or not, I don't care, but know the difference between gas quality and octane. It is basic science.

In reference to why someone would use 87 octane vs 93 octane, it is because they don't need 575 hp on tap for a daily driver. So they would rather save $500/year instead of literally burning it up for no reason.

BTW, your base model 5 series example also has turbochargers but you recommend 87 octane for that car. This further makes your post even more confusing.

[EnVe46]

Originally Posted by thebmw

You are implying that lower octane will "detroy" an engine but then you say it will just reduce performance. Do you know what octane is? It has NOTHING to do with the quality of the fuel. So you can agree or not, I don't care, but know the difference between gas quality and octane. It is basic science.

In reference to why someone would use 87 octane vs 93 octane, it is because they don't need 575 hp on tap for a daily driver. So they would rather save $500/year instead of literally burning it up for no reason.

BTW, your base model 5 series example also has turbochargers but you recommend 87 octane for that car. This further makes your post even more confusing.

If you could read, I said at the minimum, would reduce power. And if you don't NEED 575hp, why buy it to begin with?! It's ludicrous.

Also, again if you read, I said high horsepower turbo engines. A 240hp four cylinder isn't high horsepower.

While octane doesn't dictate quality of gas, point is the engine isn't designed to run on 87. If you want to run 87 to save a measly $500/year, save THOUSANDS and buy something less prestigious, less flamboyant, less maintenance, less everything. Your logic is terrible.