UNLEADED FUEL 100
09-11-2004, 02:58 PM
#21
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Enough with the knock....knock jokes.
In ECU controlled cars with a knock sensor, the engine operates at the highest advance possible for the temperature, air mixture and octane. If you get knock, to protect itself, the engine retards the timing which kills power. These E60 engines have a high compression ratio and don't use turbo or supercharging, so the highest octane is needed. Regardless of the octane standard, the higher octane gas will allow the engine to operate with maximum advance. The book says to use premium gas, otherwise, going up a hill fully loaded in the summer may lead to damaging knock enven the ECU can't fix. Furthermore, as the engine ages, it tends to knock more easily, so to rotect the engine, highest octane levels are needed. It is also my recollection that the myterious black box in the car registers the knock frequency and they can thus tell the quality of gas you are using if nothing else is malfunctioning. Defeating some polution controls can increase knock, or having a vacuum leak somewhere. Driving short distances (granny to church and shopping) regularly will increase knock due to carbon buildup over time.
I don't worry about these things because of the warranty and maintenance BMW offers. I just pay for the best gas I can get. BTW, you can get higher octane with the gasohol some places here have (10% alcohol). The gas is cheaper but the performance and mileage suffered when I tried it by accident the one time.
In ECU controlled cars with a knock sensor, the engine operates at the highest advance possible for the temperature, air mixture and octane. If you get knock, to protect itself, the engine retards the timing which kills power. These E60 engines have a high compression ratio and don't use turbo or supercharging, so the highest octane is needed. Regardless of the octane standard, the higher octane gas will allow the engine to operate with maximum advance. The book says to use premium gas, otherwise, going up a hill fully loaded in the summer may lead to damaging knock enven the ECU can't fix. Furthermore, as the engine ages, it tends to knock more easily, so to rotect the engine, highest octane levels are needed. It is also my recollection that the myterious black box in the car registers the knock frequency and they can thus tell the quality of gas you are using if nothing else is malfunctioning. Defeating some polution controls can increase knock, or having a vacuum leak somewhere. Driving short distances (granny to church and shopping) regularly will increase knock due to carbon buildup over time.
I don't worry about these things because of the warranty and maintenance BMW offers. I just pay for the best gas I can get. BTW, you can get higher octane with the gasohol some places here have (10% alcohol). The gas is cheaper but the performance and mileage suffered when I tried it by accident the one time.
09-11-2004, 05:20 PM
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Originally Posted by Flowerfred' date='Sep 11 2004, 12:51 PM
[quote name='Viper786' date='Sep 11 2004, 06:32 PM']
Kyriacos
Kyriacos
Send an oiltanker of it this way for that price please
[/quote]If you pay for shipping, sure
09-11-2004, 05:21 PM
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Originally Posted by Guest_ch7656' date='Sep 11 2004, 05:48 PM
here in Socal the best we can get is 91 
09-11-2004, 05:23 PM
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Originally Posted by Iceman' date='Sep 11 2004, 04:34 PM
[quote name='Dantheman' date='Sep 12 2004, 12:24 AM'] Because they are meant for it DUH! NOW E60's are meant for 91..
That's what ? 93 octane US ?!? [/quote]
no
in the manual it says use at least 91 octane
09-11-2004, 08:19 PM
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another interesting topic 
. i've heard from the gas station owner who has something from 87 to 100 octane. 100 octane costs almost 3 times as 92 (which is something that i put in my cars over the years) and he told me i can mix and match. he gave me a small flyer indicate all the numbers (i threw it away 
). if my memory system is working properly (can't help. another year older three days ago :'(), if you put half tank 100 and half 92, it'll become full tank 96 or something like that. and he told me i don't have to put 100 octane all the time. once a month is more than enough. btw, i think i've mentioned before, we only have a few gas stations selling something above 92 octane <_<.
. i've heard from the gas station owner who has something from 87 to 100 octane. 100 octane costs almost 3 times as 92 (which is something that i put in my cars over the years) and he told me i can mix and match. he gave me a small flyer indicate all the numbers (i threw it away ). if my memory system is working properly (can't help. another year older three days ago :'(), if you put half tank 100 and half 92, it'll become full tank 96 or something like that. and he told me i don't have to put 100 octane all the time. once a month is more than enough. btw, i think i've mentioned before, we only have a few gas stations selling something above 92 octane <_<.
09-12-2004, 10:24 AM
#28
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Originally Posted by Viper786' date='Sep 12 2004, 03:23 AM
[quote name='Iceman' date='Sep 11 2004, 04:34 PM'] [quote name='Dantheman' date='Sep 12 2004, 12:24 AM'] Because they are meant for it DUH! NOW E60's are meant for 91..
That's what ? 93 octane US ?!? [/quote]
no
in the manual it says use at least 91 octane [/quote]
The German manual is a little more precise on this.
It says:
Your BMW's engine is built for use with 98octane (ROZ).
You can also use 95octane (ROZ).
You have to use AT LEAST 91 octane (ROZ).
You can also use 95octane (ROZ).
You have to use AT LEAST 91 octane (ROZ).
So, it's built for use with 98octane (ROZ)... The downgrading is for situations where there is no such 98 octane available. In some countrys there might be no 98 octane, the highest might be 95, and if the gas station ran out off it you can also downgrade and use the 91 octane. It's not recommended for daily use...
09-12-2004, 11:17 AM
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I'm afraid you won't get any horsepower or driveability increases in using gas that's higher than the BMW recommended octane. I've never seen a dyno graph on a BMW showing a hp gain with only higher octane gas. You would have to 'remap' the ECU in order to advance the timing beyone the original specifications to take advantage of the higher octane, but you'll also need to remap the fuel/air mix.
This is what aftermarket chips do, they allow the use of higher octane gas to increase hp. However, there is a limit to how much a spark advance and fuel/air mix changes will alter HP, and it's not a lot because the BMW engines have been designed for very efficient operation. Race cars use higher octane because they have much higher compression ratios, and they need a gas that resists detonation when compressed to these high values.
This is what aftermarket chips do, they allow the use of higher octane gas to increase hp. However, there is a limit to how much a spark advance and fuel/air mix changes will alter HP, and it's not a lot because the BMW engines have been designed for very efficient operation. Race cars use higher octane because they have much higher compression ratios, and they need a gas that resists detonation when compressed to these high values.
09-12-2004, 12:39 PM
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Originally Posted by Iceman' date='Sep 12 2004, 01:24 PM
[quote name='Viper786' date='Sep 12 2004, 03:23 AM'] [quote name='Iceman' date='Sep 11 2004, 04:34 PM'] [quote name='Dantheman' date='Sep 12 2004, 12:24 AM'] Because they are meant for it DUH! NOW E60's are meant for 91..
That's what ? 93 octane US ?!? [/quote]
no
in the manual it says use at least 91 octane [/quote]
The German manual is a little more precise on this.
It says:
Your BMW's engine is built for use with 98octane (ROZ).
You can also use 95octane (ROZ).
You have to use AT LEAST 91 octane (ROZ).
You can also use 95octane (ROZ).
You have to use AT LEAST 91 octane (ROZ).
So, it's built for use with 98octane (ROZ)... The downgrading is for situations where there is no such 98 octane available. In some countrys there might be no 98 octane, the highest might be 95, and if the gas station ran out off it you can also downgrade and use the 91 octane. It's not recommended for daily use...[/quote]
I believe that in michigan there are no gas stations with 91 octane... the minimum for premium is 92 from what i have seen, but most have 93..
i just got 93 octane yesterday for 1.97 a gallon. 30USD to go from around 1/4 tank to full.
