[raleedy]

87 octane? Time for the crusher.

[Maynard]

Yes, I think he should post the car for sale in the members section, probably for less than 10 grand, given the terminal engine damage already done. My deposit is in the mail.

And FWIW, most octane boosting operates on diminishing returns - each incremental rise in octane level takes more and more chemical. So you get a bonus when you downmix like this (at least with the older stuff, half 91 and half 87 would yield about 90 - even stronger effect for the lead, but we can't use that anymore )

[RPM90]

You kids are silly.

OP, there is absolutely NOTHING damaging to your engine and there won't be even if you got confused and fill up a full tank of 87AKI gasoline.

Yes, turbo engines have knock sensors that listen for combustion chamber detonation, and that signal is monitored by the ECU/ECM that will adjust timing to keep detonation/knock from becoming damaging.
When this timing adjustment occurs it typically results in the engine not developing it's full power if the driver is calling for it.
Even if you smacked the loud pedal as hard as you can your engine will not be damaged because of the lower octane fuel.

[Kiwi]

I guess Americans need reminding which fuel is required and it would be a good addition to join all the reminder alarms you Americans need in cars.

[Sportstick]

Originally Posted by Kiwi

I guess Americans need reminding which fuel is required and it would be a good addition to join all the reminder alarms you Americans need in cars.

It's not so much that we are all imminent dementia patients as much as our hyper-litigious society has exploited "failure to warn" causes of action with a history of excessive recoveries.

[bimmerfile]

Originally Posted by jcl89

After a long day of work I wasn't paying close attention at Chevron, filled half tank with 87. Drove the car home (21 mi) in Eco Pro mode.

I'm guessing the car has knock sensors, so I figured I should be OK - just stay off the boost and then fill back up with 91 when it's quarter tank?

The biggest issue here may not not the octane rating, but rather the ethanol in most 87 octane fuels.

Page 170 of the Owners manual "Gasoline below the minimum fuel grade may impair engine performance".
But on the same page it also states "Fuels with a maximum ethanol content of 10 %, (i. e., E10, may be used for refueling . Do not use a fuel with a higher percentage of ethanol recommended or one with other types of alcohol, e.g. M5 to M100; otherwise this could damage the engine and fuel supply system."

Dunno, but to me, potentially damaging engine and fuel supply system would appear to trump impairing engine performance as a possible source of concern.

[M235ForNow]

Just to add to other's comments - the car's ECU will take care of the lower octane gas by lowering output. it's also the case that putting cheaper gas in on purpose (to save $) doesn't tend to work out because the gas mileage degrades. And, at least to me, the % savings is so tiny compared to the overall cost of the gasoline (and in comparison to all other running costs) that putting anything in other than "the best" makes no sense.

[internalaudit]

So there's not risk of using 87 Octane for the life of the car?

Will the warranty and extended warranty be voided if BMW Canada catches me using 87 all the time?

[Dylan86]

Originally Posted by internalaudit

So there's not risk of using 87 Octane for the life of the car?

Will the warranty and extended warranty be voided if BMW Canada catches me using 87 all the time?

Why the hell would anyone want to do this, though? Go buy a Honda... oh wait.. No, buy a Honda, if 87oct is your thing

[Kolyan2k]

Originally Posted by internalaudit

So there's not risk of using 87 Octane for the life of the car?

Will the warranty and extended warranty be voided if BMW Canada catches me using 87 all the time?

Why would you? Are you broke?

[USA-RET]

Originally Posted by internalaudit

So there's not risk of using 87 Octane for the life of the car?

Will the warranty and extended warranty be voided if BMW Canada catches me using 87 all the time?

Probably yes if you use it continuously. So if you are running out of gas and the station only has 87 octane put some in to get you home or to another station, then fill w/ 91/93. No harm no foul.

If you have engine damage and it can be diagnosed to using cheap fuel (long term), then likely the warranty will not cover any costs.

For the sake of $6 per tank difference, don't risk damaging a $50K investment.

[Lew Carrum]

89 octane? Never seen here in the UK, or is it what we used to call 2 star?

[MessageMan]

Thanks to some users on this thread, I am going to invest $4 into this:

https://www.ebay.com/itm/Warning-Lab...-/282424193833