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View Full Version : Regular low octane by mistake instead of Premium high octane - any Quick Fix?


new_kid_in_town
08-01-2012, 09:55 PM
Hey friends, I have my 2006 525xi... All along I have been using Premium 93 octane gas... On my way back today I was running on reserve... It was very late and the only nearby gas station I could pull in was a Fuel One gas station (first and most likely the last time of my life)... I ordered premium but the attendant at the gas station put regular... I was too tired and did not notice until he handed me over the receipt... I'm lucky that I noticed the price and realized what happened... But it was too late and damaged being already done... I have now a tank full of regular 87 octane gas.

I need to know the possible quick fix and the possible risk I might run into... Is adding octane booster a good solution?

As always thanks in advance for your suggestions and help.

Gilgorm
08-01-2012, 10:11 PM
Drive the car. It will not run great but all the computerized controls will compensate for the low octane. After a quarter tank, fill with your 93 and keep filling whenever the tank gets to a quarter. It will take a while but the car will recover.
OR suck the 87 out and donate it to someone who needs regular. Doubt octane booster will work, but I don't think it works anyway under normal circumstances.

new_kid_in_town
08-01-2012, 10:28 PM
How do I really suck it out? Is there any easy way doing that?

bkun
08-01-2012, 10:36 PM
Insert a hose into the tank and suck it out the first time by mouth and it will keep flowing.

1naztyx5
08-01-2012, 10:37 PM
the car will be ok, take advantage and instead of octane booster put some fuel injection cleaner or fuel system cleaner of some sort.

new_kid_in_town
08-01-2012, 10:39 PM
When I wait to get that done, is it ok to keep the car sitting in the driveway or drive few miles here and there?

1naztyx5
08-01-2012, 10:40 PM
Insert a hose into the tank and suck it out the first time by mouth and it will keep flowing.

no this would not work! most cars after1997 have some sort trap that will not allow this .

new_kid_in_town
08-01-2012, 11:05 PM
Going by what 'Gilgorm' suggested i.e. refilling after every quarter of gas loss with 93 octane gas... here is my math...

87 93
100% 0% 87
75% 25% 88.5
75% 25% 89.625
75% 25% 90.46875
75% 25% 91.1015625

So, basically after the 4th cycle it reaches the suggested 91 octane level... After that I can pretty much burn the whole thing or may be do few more half filling...

50% 50% 92.05078125
50% 50% 92.52539063
50% 50% 92.76269531
50% 50% 92.88134766

Trying to keep my mind occupied to something more fun like mathematics and to the power of Excel!!!

Remind me the 'half-life' property of radioactive decay :)

I'm essentially hearing it is NOT too bad and that gives me huge amount of peace.

Thank you all! I will keep reading your posts. Please keep it coming.

new_kid_in_town
08-01-2012, 11:12 PM
the car will be ok, take advantage and instead of octane booster put some fuel injection cleaner or fuel system cleaner of some sort.

When should I be adding it? Should I wait until I burn it all? How many times should I add it and in what kind of frequency?

bimmerfan52
08-01-2012, 11:15 PM
Hey friends, I have my 2006 525xi... All along I have been using Premium 93 octane gas... On my way back today I was running on reserve... It was very late and the only nearby gas station I could pull in was a Fuel One gas station (first and most likely the last time of my life)... I ordered premium but the attendant at the gas station put regular... I was too tired and did not notice until he handed me over the receipt... I'm lucky that I noticed the price and realized what happened... But it was too late and damaged being already done... I have now a tank full of regular 87 octane gas.

I need to know the possible quick fix and the possible risk I might run into... Is adding octane booster a good solution?

As always thanks in advance for your suggestions and help.

Not to worry! If you drive moderately and do not push the engine hard you will have no problem and probably will not even notice the difference.

The engine has sophisticated knock sensors to protect itself from damage. The computer will change the electronic timing and fuel delivery to compensate.

Run half of the tank out, then top it off with 93. Then run the tank dry and fill with 93 and you are done.

1naztyx5
08-01-2012, 11:19 PM
When should I be adding it? Should I wait until I burn it all? How many times should I add it and in what kind of frequency?

now that you have a full tank of 87,and just drive it...frequency? well is really up to you, I do it every 3 months.

dwlink
08-02-2012, 12:04 AM
Keep things simple - just drive it conservatively until you have a 1/4 tank and then fill with 93. After that, I wouldn't even sweat it anymore.

todd92
08-02-2012, 04:19 AM
Geez. Just drive it.

racooper3
08-02-2012, 06:18 AM
geez. Just drive it.

amen.

w5lx
08-02-2012, 07:29 AM
Don't worry about it. Thousands of other people are driving around in their 525's using nothing but 87 octane and I've never read a single post about an engine blowing up due to using regular gasoline. Your engine is designed to adapt to 87 octane. Fuel mileage may suffer slightly but I doubt if you'd ever notice it.

patryan
08-02-2012, 09:16 AM
+1 with everyone else. You won't ruin your engine. It'll automatically sense the lower octane fuel and drive like a dog. As long as you don't hear any knock on acceleration it'll be fine... just drive conservatively until you burn that gas and replace with premium.

gmcclintock
08-02-2012, 09:18 AM
Dude if you still worry about drive the car or if you still have a lower grade fuel in it the best way to work around it is to add octane booster...I'm surprised no one in this section even mentioned it, but I shouldn't expect it from BMW drivers lol...oh and by the way I'm on my 3rd so think before you start bashing hahaha.

crowz
08-02-2012, 09:18 AM
Put a bottle of 104+ octane boost in it and dont buy low octane gas anymore. Problem solved :)

gmcclintock
08-02-2012, 09:22 AM
Put a bottle of 104+ octane boost in it and dont buy low octane gas anymore. Problem solved :)

++++ ^^^^^ Good advice right there lol

Jred
08-02-2012, 10:02 AM
It's not like he put diesel in it, shouldn't destroy your engine, just drive.

ECSTuning
08-02-2012, 10:36 AM
Deep breath, it'll be fine. With lower octane fuel you'll not be at an optimal performance level and fuel economy may suffer slightly and that's about it.

X308Black
08-02-2012, 10:54 PM
lol wowowowowow i hardly ever put high test. Let the computer do the work.
waste of money imo unless you have mods and tunes.. ( preparing for flames) lol

and I STILL get 30 on the hwy.

l1tech
08-03-2012, 06:47 PM
Seriously...just drive it.

new_kid_in_town
08-03-2012, 07:42 PM
Thank you so much guys! You guys are great and this forum is simply awesome!

Yes, I'm driving gently and so far did not experience anything bad.

2chill
08-03-2012, 10:31 PM
Just drive it normally. At 1/2 a tank fill it up again with Premium and then you'll average around 90-91 octane and you will be fine. The real damage occurs when people continually fill up with nothing but 87 octane. Burning only 1/2 tank of it will do no damage.

l1tech
08-05-2012, 07:59 AM
The real damage occurs when people continually fill up with nothing but 87 octane..


What kind of damage are we talking about??

PolkNole
08-05-2012, 09:31 AM
What kind of damage are we talking about??

An occasional backfire?

crowz
08-05-2012, 10:07 AM
What kind of damage are we talking about??

That ones easy to explain in a way that will make sense.

The pinging from low octane is the fuel pre detonating before the spark plug actually ignites the fuel. This can also cause a symptom called dieseling in gas motors. Basically you turn the key off and the motor keeps running with lots of valve noise till it burns the fuel out of the fuel rails. Whether this can occur or not depends on how the fuel injection works. Was a real problem on carburetor and mechanical fuel injected vehicles more so than fuel injection since modern fuel injectors wont fire without the computer.

So you have a piston coming up to the top of the head on a compression stroke and it needs to make it all the way up before the spark event happens so the explosion of the gas and fuel mixture can smoothly push the piston down.

If the charge explodes early while the piston is still compressing you get pinging and knocking. This can destroy a gas motor eventually since its putting a ton more pressure on everything with the fuel igniting to soon.

Now there is no difference between pinging and knocking from a technically stand point but a mechanic looks at these as symptoms of how bad the problem is.

Low octane fuel will cause both symptoms. A knock is worse than a ping. But again they are the same thing. But a mechanic knows a knock can cause a motor to let go where pinging is usually not as bad. Pinging happens when the timing is advanced to far or you have mild octane issues.

Knocking occurs earlier in the compression stroke so the piston is even further down the cylinder. Again there isnt really a difference just the way the terms are used.

So thats why running low octane fuel for long periods can be a very bad thing to do.

luigi524td
08-05-2012, 10:33 AM
For what it's worth, I have from time to time when supplies of Premium Gasoline were unavailable, used a tank or two of "regular" gasoline. I've had no mechanical issues as a result though I did notice better gas mileage using high test / premium gasoline. As for "performance" ... well, I'm driving a 530xi, so not even Sunoco Ultra will transform my car into a ROCKET SLED :rofl:


Drive your car 'normally' ... when you have the opportunity to top off or refill use the higher octane stuff do it.

I have no comment to add about "octane boosters" ... occasionally (once or twice a year) I use Chevron Techron Fuel Cleaner.

2chill
08-05-2012, 11:22 AM
If the charge explodes early while the piston is still compressing you get pinging and knocking. This can destroy a gas motor eventually since its putting a ton more pressure on everything with the fuel igniting to soon.

I was just involved in this conversation not to long ago on my job. A coworker's mother was putting nothing but 87 octane in her 7 series. Car had to wind up getting towed into BMW with engine damage. BMW analyzed the gas and came to the conclusion that the damage was caused by continuance use of low octane gasoline and informed her this voided the warranty. She was told she would have to foot the bill for major engine repairs. Not sure how it all played out.

crowz
08-05-2012, 11:27 AM
Your not really going to get more power out of higher octane itself. The correct octane allows the motor to perform at its maxium power level by not having to retard timing from pinging. So whatever level stops the racket basically is all you need. The only problem with trying to get away with running under the recommended octane level is just because you dont here the pinging/knocking the computer does :)

Running it on lower than ideal octane isnt going to instantly kill the motor or anything. Best thing to remember is if you hear ping/knocking just back off the pedal. Hammering down on the pedal or keeping it pushed far enough that its making noise will damage the motor eventually. As long as you dont hear any noise then no damage is being done at all.

l1tech
08-05-2012, 06:28 PM
I'm an ASE Master Tech with over 25 years experience and it is alwasy amusing to hear how people think their cars operate. Years ago before cars had computer controls there was alot of truth to some of the opinions here. Maybe my owners manual is a misprint but it clearly states that 91 is recommended but the minimum required is 87 and that absolutely no engine damage will occur if 87 is used. ONLY IF LESS THAN 87 IS USED MAY ENGINE DAMAGE OCCUR.

racooper3
08-06-2012, 11:08 AM
I'm an ASE Master Tech with over 25 years experience and it is alwasy amusing to hear how people think their cars operate. Years ago before cars had computer controls there was alot of truth to some of the opinions here. Maybe my owners manual is a misprint but it clearly states that 91 is recommended but the minimum required is 87 and that absolutely no engine damage will occur if 87 is used. ONLY IF LESS THAN 87 IS USED MAY ENGINE DAMAGE OCCUR.

I was actually waiting for someone to recommend that they owner put AVGAS in the tank to bring it up to the right octane level. I am encouraged that nobody stated that. :confused: