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89 Octane Gas ok for my 540i?

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Is it ok to use 89 Octane gas (Chevron with Techron) in my 99 V8 540i? I live in Canada where the price of gas is quite high and the difference between 91 and 89 is significant on the pocket book.

Any comments, recommendations?

:dunno:
1 - 20 of 38 Posts
I say go 91, if the additional cost is a few more bucks a fill up I think it's worth it. It's said that o2 sensors and cats will last longer with higher octane gas, how true that is, I don't know. My take though is if you're going to spend the money to maintain the car etc. you might as well put the best gas in you can, I personally go with 93.
I agree. It makes a difference in how the E39 runs.
The savings from using lower octane gas may be less than you think. The milage will be lower, so you will buy the gas cheaper but use more for the same distance.
Team 93 :thumbup:
I personally go with 93.
These are theoretical questions

What is octane? Why is JP5 (Jet propellant 5 - the most powerful Jet propellant) closer to diesel fuel than gasoline? When these are answered the original posters question is much more worthy of a 'real' response and not I recommend, or others recommend...or why do manufacturers recommend. The real answer is?

The answer lies in predetonation...
JP5 is refined to be diesel fuel, not gasoline. Diesel fuel is rated by Cetane number, relaed to self-ignition properties.

Octane rating is a measure of resistance to self-ignition.

My gas cap recommends a minimum of 89 pump octane (R+M/2). So, if your car runs okay with 89, use it. In CA, the difference per gallon between 89 and 91 is $0.20. With gas at $3.70+, that's not much.
Most fuel these days is real garbage...best bet is to use highest octane and a decent stabilizer...even marine stabilizer to combat ethanol side effects...
food for thought

JP5 is refined to be diesel fuel, not gasoline. Diesel fuel is rated by Cetane number, relaed to self-ignition properties.

Octane rating is a measure of resistance to self-ignition.

My gas cap recommends a minimum of 89 pump octane (R+M/2). So, if your car runs okay with 89, use it. In CA, the difference per gallon between 89 and 91 is $0.20. With gas at $3.70+, that's not much.
Is accurate...the thing to note is diesel does not ignite with spark it ignites with compression. Which is why manufacturers with HIGH COMPRESSION engines recommend higher octane ratings. Because as you cite higher numbers are the resistance to predetonation or ignition by compression and flash point which is affected by temperature and altitude.

Higher octane does not 'ignite faster' or 'give a more powerful' ignition process. It simply resists predetonation more, it has nothing to do with carbon build up. Now my answer to the OP is sure you can run the lower octane rating especially in cooler climates and easier driving ...But not in high heat and hard driving. conditions and this is my $.02
Yep! Only shell V-POWER for mine.
TEAM V-POWER :thumbup::D
To answer your question, 87 is minimum to use in all 99 and newer tu engine cars, 91 is recommended. It's on the sticker on your fuel cap.

you will loose mpg and performance with lesser octane. I don't think any damage will occur with the stock tune but you really won't have any benefits from going with the lower octane. You will save a few $ each time at the pump but will be at the pump more often. I think cost wise it all works out to be about the same.
your car is so clean! evven gas fill area

To answer your question, 87 is minimum to use in all 99 and newer tu engine cars, 91 is recommended. It's on the sticker on your fuel cap.

Must have used lots of q-tips
your car is so clean! even gas fill area

To answer your question, 87 is minimum to use in all 99 and newer tu engine cars, 91 is recommended. It's on the sticker on your fuel cap.

Must have used lots of q-tips
LOL, yup, the Boston Chapter concours is next weekend.
Must have used lots of q-tips
Well...according to the two questions you asked...JimLev's reply & the text from the owners manual answers question #1 ...and some of the other replies above answers question #2. :D

Overall...understanding the definition & meaning of "recommendation" and "minimum octane requirement"...makes this oft asked question a really simple one to answer. :)



1. Is it ok to use 89 Octane gas (Chevron with Techron) in my 99 V8 540i?
2. Any comments, recommendations?

:dunno:
That's EZ when the car doesn't leave the garage. :thumbup:
Must have used lots of q-tips
Oh come on, she's got 137K on the odometer.
That's EZ when the car doesn't leave the garage. :thumbup:
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