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Didn't use premium gas, problem?

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Old 09-12-2010 | 04:04 PM
  #11  
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Every thread is full of mis-information it is unbelievable. I admit a couple times I have posted some incorrect info but largely I dont comment unless I am 100 percent sure on something.

With that said you can drive the life of the car on 87 octane with no difference in engine life or wear. Providing one thing-which is the 87 had the same fuel cleaners as the 91/93 which most do now. It used to be only the high octane gas had the "cleaners" that are in gasoline but now all do. These are what keeps the engines clean and carbon free which means working properly.

Fuel economy will be absolutely no different-it is not possible.

Performance at its max is what is changed. lower octane combusts more easily. Heat generally is what combusts gasoline and things that make more heat cause combustion. So if you drive at WOT and are pushing the car the 87 octane will spontanseously combust causing "pre ignition" which means it starts burning at the wrong time, before the spark plug would have "sparked" the gas to burn. This means a pressure wave is created that works against cylinder motion and is what is damaging to an engine. Todays cars and knock sensors. Knock is the sound pre-ignition makes by this pressure/sound wave against the chamber. When our engines sense knock they adjust the engine-ultimately making a richer A/F mixture which provides more fuel compared to air which cools everything down and makes it less easily combustible and pulls back the ignition timing, meaning it ignites the gas well before it would otherwise and before it has time to "pre-ignite" or auto combust itself-while it pulls back timing, it also adjusts the engine to work with this earlier timing so the pistsons are moving appropriately for when the fuel is being ignited. So while combusing earlier in the stroke, the pistons are not moving as if it was going to combust laster, however that loss of pressure from igniting it earlier causes the loss in HP-especially in a turbo car which only makes it easier to pre-ignite due to higher pressures in the cylinders.

Other things like temperature (summer 100 degree heat) cause an engine to get more hot etc- So performance will go but your engine will compensate fine. Unless you are a turbo you probably would never know the difference.

It is robably one of the biggest myths that you have to run premium fuel on any modern car-if you are the type to rarely push the car, you would have no use for premium. FOr those that do push the car or drive in the desert-premium is more appropriate

Best thing to do is drive with this tank-do a test, and monitor your mgg for this tank and report back. I promise you it is no different than a premium tank. Fill up with premium once empty
Old 09-12-2010 | 06:32 PM
  #12  
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I would not worry about it or try mixing it out. Your gas mileage will suffer a little because of the retarded timing needed to run properly. Once the gas is out, and premium is in, everything will return to normal. I have ran regular in all my cars, (except the diesel) even though premium is recommended, this was during the time when premium was well over $5 a gal. No problems except less gas mileage, and less performance.
Old 09-12-2010 | 07:15 PM
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I used the lowest octane available for 207,000 miles in my 95 740i (it required 91 or higher octane) with no problems whatsoever.
Old 09-12-2010 | 07:42 PM
  #14  
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No problem.just stay away from performance driving and steep hills until it's gone.
Even so the sensors will keep you safe.
It's like a few big macs arent going to give you a heart attack!

I think even mid grade would be ok for normal use.
Old 09-12-2010 | 07:50 PM
  #15  
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less than premium will cause your engine to knock. drive it slow'ish and you should be fine.

btw, don't drive drunk
Old 09-12-2010 | 09:42 PM
  #16  
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Originally Posted by Diamond
Every thread is full of mis-information it is unbelievable. I admit a couple times I have posted some incorrect info but largely I dont comment unless I am 100 percent sure on something.

With that said you can drive the life of the car on 87 octane with no difference in engine life or wear. Providing one thing-which is the 87 had the same fuel cleaners as the 91/93 which most do now. It used to be only the high octane gas had the "cleaners" that are in gasoline but now all do. These are what keeps the engines clean and carbon free which means working properly.

Fuel economy will be absolutely no different-it is not possible.

Performance at its max is what is changed. lower octane combusts more easily. Heat generally is what combusts gasoline and things that make more heat cause combustion. So if you drive at WOT and are pushing the car the 87 octane will spontanseously combust causing "pre ignition" which means it starts burning at the wrong time, before the spark plug would have "sparked" the gas to burn. This means a pressure wave is created that works against cylinder motion and is what is damaging to an engine. Todays cars and knock sensors. Knock is the sound pre-ignition makes by this pressure/sound wave against the chamber. When our engines sense knock they adjust the engine-ultimately making a richer A/F mixture which provides more fuel compared to air which cools everything down and makes it less easily combustible and pulls back the ignition timing, meaning it ignites the gas well before it would otherwise and before it has time to "pre-ignite" or auto combust itself-while it pulls back timing, it also adjusts the engine to work with this earlier timing so the pistsons are moving appropriately for when the fuel is being ignited. So while combusing earlier in the stroke, the pistons are not moving as if it was going to combust laster, however that loss of pressure from igniting it earlier causes the loss in HP-especially in a turbo car which only makes it easier to pre-ignite due to higher pressures in the cylinders.

Other things like temperature (summer 100 degree heat) cause an engine to get more hot etc- So performance will go but your engine will compensate fine. Unless you are a turbo you probably would never know the difference.

It is robably one of the biggest myths that you have to run premium fuel on any modern car-if you are the type to rarely push the car, you would have no use for premium. FOr those that do push the car or drive in the desert-premium is more appropriate

Best thing to do is drive with this tank-do a test, and monitor your mgg for this tank and report back. I promise you it is no different than a premium tank. Fill up with premium once empty

Very very true!!! Unless u have a MODIFIED forced induction vehicle, it wouldnt really matter but if you do push ur car whether FI or NA, just put th premium in. U might lose more MPG if you push the car but I am sure you wouldnt push the car since you put regular gas in there.
Old 09-12-2010 | 09:42 PM
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I really appreciate all the replies. Going off of what I've read, I will drive it grandma style for the next week or two then refill when on empty.


Originally Posted by tuffluck
btw, don't drive drunk
Ha, I promise I wasn't drunk. Distracted yes, drunk no.
Old 09-12-2010 | 10:11 PM
  #18  
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Originally Posted by ryan60isu
I really appreciate all the replies. Going off of what I've read, I will drive it grandma style for the next week or two then refill when on empty.




Ha, I promise I wasn't drunk. Distracted yes, drunk no.
haha! just messin' with you. you will be fine on the lower octane if you take it easy.
Old 09-12-2010 | 10:16 PM
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Your car will be fine....
Old 09-13-2010 | 09:00 AM
  #20  
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again dude-drive as you NORMALLY would-you will probably lose impercievable power unless you were in a 90 plus degree day, or pushing it back and back run after run. One hard WOT with low octane you may lose 10hp--and your computer compensates before the knock does any damage--just drive it like you would otherwise--

after actually typing this its kind of silly why I use 93 octane--it really is quite a waste but hey for the difference the mental placebo effect is worth it but certainly if I got a free tank of 87 i wouldnt pass it up



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