Accidentally Dropped 87 Octane

[hyphy1]

Lots of things on my mind this season, oblivious to the routine, and accidentally filled her up with 87 octane. Kind of a noob question, but then again, I'm also worried because I always fill her up on 91, and this is the first (and only) time this has happened. BMW recommends 91 octane, but should I be worried about performance, engine life, engine knock, timing, and etc...?

[IEDEI]

Originally Posted by hyphy1

Lots of things on my mind this season, oblivious to the routine, and accidentally filled her up with 87 octane. Kind of a noob question, but then again, I'm also worried because I always fill her up on 91, and this is the first (and only) time this has happened. BMW recommends 91 octane, but should I be worried about performance, engine life, engine knock, timing, and etc...?

lol...naaaah nothing will happen. tomorrow you should go to an auto store and buy some octane booster. just add it into the gas tank if you're worried.

your car won't blow up or anything with 87....it just won't perform to its optimal level.

[Adam135]

The engine has so many sensors it will adjust accordingly. If you have a tune I would throw some octane booster in.

[Bob Z.]

And just put some prem. in when it drops by a 1/4 tank, which will dilute the 87 over time. But you may not even notice it depending on how you drive nor will it harm the car.

But if it were diesel that was added...

[nacaruh]

It's okay, there are some people in this world that will just put in 87 octane in their BMWs for years.................................

[631twentyeighteye]

Should be fine as long as you don't beat on it. Treat it nice until you can fill it up with some premium. Also, octane booster does absolutely nothing, so don't waste the money on it.

[Overpar56]

Drive it as hard and fast as you can and burn off the 87.

Once won't kill ya. You might notice some performance degradation if you get on it but as a previous poster said, the amount of sensors will account for lower octane. You might notice lower MPG for the tank.

[cheshirecat79]

It'll be fine. Funny thing is, if you consult your owner's manual, it'll warn that detonation might occurr during warm days but "this will not harm the engine" (at least in the 2008 version).

You know your engine is pretty stout when the manual is telling you that it can soak up detonation misfires without an issue.

[hyphy1]

thanks guys. good to know our engines can take the beating. looks like i'll be waiting 'til quarter-tank to fill'er up again. won't be spending the cash for octane booster.

[Deutsche-Broke]

Just my .002, but you spent better money on 87 octane fuel than a so called, "octane boost" in a bottle.. That's one of the biggest lies in automotive history next to STP.

If you want an increase in octane, head to the airport and get some AV100 av gas.. And no, it isn't cheap and it will trash your valves over time.. God help you if you have a turbocharger.

Otherwise, don't worry about it.. I watched the dealer pump 87 into mine before I left and knew better.. The computer took care of it just fine.. Free gas is free gas.

I just try to avoid anything under 92.. But I'm not gonna kill myself if it drinks 87 or 89 for a few days..

Just stay away from the additives.. That's a joke..

[Overpar56]

Originally Posted by Deutsche-Broke

Just my .002, but you spent better money on 87 octane fuel than a so called, "octane boost" in a bottle.. That's one of the biggest lies in automotive history next to STP.

If you want an increase in octane, head to the airport and get some AV100 av gas.. And no, it isn't cheap and it will trash your valves over time.. God help you if you have a turbocharger.

Otherwise, don't worry about it.. I watched the dealer pump 87 into mine before I left and knew better.. The computer took care of it just fine.. Free gas is free gas.

I just try to avoid anything under 92.. But I'm not gonna kill myself if it drinks 87 or 89 for a few days..

Just stay away from the additives.. That's a joke..

I wonder how many BMW service loaners get 87 octane? My guess...all.

[shah269]

Well your car will now weight 0.0001kg more and the CG will be 0.0001mm from where it should be. And according to the South African version of Car and Driver when they testes a 135 running on 89 vs one running 92 not only was the 89 0.001seconds slower around the race track but when it crossed the finish line it's engine detonated and fired all 6 cylinders through the head through the hood and took out the 6 baby otters that were in a holding tank near the race track....killed those little furry bastards...and who kills an otter! They freaking hold hands when they sleep! But the driver was unharmed due to utilizing a 7 point after market harness he had bought on ECS tuning!
Is what your ricky racer taco bell loving tuner will tell you…
Odds are your dealer just like my local dealer has been filling up cars with 89 for longer than you can remember. Your car will be ok!
Hell odds are with the economy in the dumps for the past 13 years or so the 89 you put in the car was ‘fresher’ than the 92 you usually put it and probably had a lower water content and I’m willing to bet good money it had less ethanol accidentally mixed in.
You are 1000000% ok
If you are super worried grab some Chevron Techron from Costco which sells for about $15 for a box of 6 which is oddly the price your dealer will charge you for a single bottle which was exported from NJ to Germany and then imported from Germany back into NJ.

[rking117]

you will notice that you will get bad gas mileage for this tank but no harm. I personally always use 93 though just because it is cleaner burning (and also because 91 is harder to find here)

[Overpar56]

Loved that baby otter comment.

[shah269]

Originally Posted by Overpar56

Loved that baby otter comment.

Can you tell that i'm the creative type!
I keep telling the people of Cosmo and Road and Track to hire me!
But they are like nooooooooooo you use midde grade in your 135 by accident...shame on you! And how dare you not use imported German Air for those tires!
Didn't you read the Colombian issue of Motor Trend!
That American Air slowed the car down by 0.001 seconds and made the car look fat!

[IEDEI]

Originally Posted by shah269

That American Air slowed the car down by 0.001 seconds and made the car look fat!

*makes note*

this changes everything.

[jmcphillips1]

it's perfectly fine...I burn 87 all the time in mine. Runs just fine.

[BeachNut]

Originally Posted by jmcphillips1

it's perfectly fine...I burn 87 all the time in mine. Runs just fine.

I've heard 87 ruins the engine, but my brother has a 328 which he never put premium in and said his car is fine.

Is this an "urban legend"?

Thinking of buying a 128 Convertible. I'd put premium in only because I won't drive it that much, and when I do . . .

Beach Nut

[jmcphillips1]

Originally Posted by BeachNut

I've heard 87 ruins the engine, but my brother has a 328 which he never put premium in and said his car is fine.

Is this an "urban legend"?

Thinking of buying a 128 Convertible. I'd put premium in only because I won't drive it that much, and when I do . . .

Beach Nut

well mine is 3 years old and I've never had any type of problem with it what so ever. Might long term (5+years) have an affect on it? Maybe but in 3 years it's been just fine.

[Overpar56]

Originally Posted by shah269

Can you tell that i'm the creative type!
I keep telling the people of Cosmo and Road and Track to hire me!
But they are like nooooooooooo you use midde grade in your 135 by accident...shame on you! And how dare you not use imported German Air for those tires!
Didn't you read the Colombian issue of Motor Trend!
That American Air slowed the car down by 0.001 seconds and made the car look fat!

Too bad we can't get 96 octane in Ohio. It would be fun driving in reverse.....

[Andrewcoja]

It's important to know what the octane rating is. The difference between a higher octane and a lower octane is when the fuel detonates. If you run 87 octane in a car designed for 91, the fuel will detonate before it is supposed to. In an older engine, this can be bad. In many new engines, the computer will notice this and change the timing of the engine to adjust for the lower octane. The reason why some engines (BMWs and some other higher end brands) require high octane is because they run higher compression. The compression causes the fuel to combust early and the higher octane helps the fuel stay uncombusted until the crankshaft is in a position for the power stroke of that cylinder. In most cases, combusting early because of lower octane isn't too bad, you just won't receive all the power that combusting at the right time would.

Running a higher octane than what is suggested by the manufacturer does absolutely nothing. The arguments of people who run octane ratings other than what the manufacturer recommends are worthless. Both the people who say "You use premium? You can put regular in and be just fine." or "I use premium because it's better." There's no such thing as regular or premium gas. It's all gas, just the octane rating changes. 89 octane gas doesn't even exist as the pump just mixes in 87 and 91 (or 93).

So in the end, your car is fine. The ECU will change timing to adjust for the 87 fuel and go back to normal when it gets 91-93 fuel back.