Octane rating needed for full performance ? - Page 3

Wolverine · 6th January 2006, 20:31

Quote:

Originally Posted by richhaywood

I've just scanned an article from Evo magazine (uk) testing octane ratings on the M5, its about 10mb though, can i email it to anyone to host it ?

Can you give us a summary?

richhaywood · 6th January 2006, 20:36

heres a link: http://groups.msn.com/M5Webspace/sho...hoto&PhotoID=2

ok sorry that didn't come out as clearly as i thought, basically the shell optimax gave 518bhp, BP ultimate 534bhp, but basically they thought the M5's computer is that quick that it compensates for having a poorer quality fuel. It also made a key point, don't buy petrol (gas) from a garage that doesn't get used often as its not the octane that reduces the power but fuel that is not "fresh." This is due to fuels having differen coctails of cleaners in them.

Hope this helps

Wolverine · 6th January 2006, 21:28

Quote:

Originally Posted by richhaywood

heres a link: http://groups.msn.com/M5Webspace/sho...hoto&PhotoID=2

ok sorry that didn't come as clearly as i thought, basically the shell optimax gave 518bhp BP ultimate, 534bhp but basically they thought the M5's computer is that quick that it compensates for having a poorer quality fuel. It also made a key point, don't buy petrol (gas) from a garage that doesn't get used often as its not the octane that reduces the power but fuel that is not "fresh." This is due to fuels having differeny coctails of cleaners in them.#

Hope this helps

Octane ratings of the Shell and BP? The 534 sounds very very strong. Was this measured at the crank, or calculated based on WHP? Did they get a WHP reading? Thanks for the post.

NobleM400 · 6th January 2006, 21:48

Quote:

Originally Posted by richhaywood

I've just scanned an article from Evo magazine (uk) testing octane ratings on the M5, its about 10mb though, can i email it to anyone to host it ?

Email it to me, I'll photoshop to a readable size and host. email me

SWP · 6th January 2006, 21:57

Your M5 will run just fine on 91 octane (Premium in CA).

Modern engine all have anti-knock systems that will adapt the engine to lower than recommended octane levels.

BMW recommends 92 octane for the M5, but 91 octane is readily available in CA because they add that gasoline derivative for environmental purposes (I can't remember the name).

The one octane difference will not affect performance. It may reduce your fuel consumption a bit, but nothing to worry about.

brutus · 6th January 2006, 22:40

Quote:

Originally Posted by SWP

Your M5 will run just fine on 91 octane (Premium in CA).

Modern engine all have anti-knock systems that will adapt the engine to lower than recommended octane levels.

BMW recommends 92 octane for the M5, but 91 octane is readily available in CA because they add that gasoline derivative for environmental purposes (I can't remember the name).

The one octane difference will not affect performance. It may reduce your fuel consumption a bit, but nothing to worry about.

I don't think so or BMW wouldn't have put in the Euro English manual:

"> The engine of your BMW M5 is rated to run on: Super Plus/premium plus fuel, octane number 98 RON. Fill up with fuel of this grade whenever possible, so that hte niminal performance and fuel consumption values are achieved."

And: "> The minum permissible grade is: Premium-grade unleaded fuel, octane number 95 RON."

Don't have my US manual handy but 98 RON is ~~ 93 AKI or (RON+MON)/2 as we use in the US and ~~ 91 AKI for minum permissible grade.

It's true the car will run on 91 due to anti knock sensors but what do you think the EMC does when it sense knock ? What it does will definitely impact performance.

Further, the nominal value for octaine is based on atmospheric conditions that are nearly ideal (altitude: sea-level, humidity: moderate (don't remember the value), and tempature: moderate (don't remember)) so the higer the altitude, the lower the humidity, and the higher the tempature all increase the octane required.

So, where did you get your info about octane rating required for performance of an M5 ?

Brutus

SWP · 6th January 2006, 23:45

I make it up, of course.

Actually, I read it on an issue of Road & Track way back when . . .

Quote:

Originally Posted by brutus

I don't think so or BMW wouldn't have put in the Euro English manual:

"> The engine of your BMW M5 is rated to run on: Super Plus/premium plus fuel, octane number 98 RON. Fill up with fuel of this grade whenever possible, so that hte niminal performance and fuel consumption values are achieved."

And: "> The minum permissible grade is: Premium-grade unleaded fuel, octane number 95 RON."

Don't have my US manual handy but 98 RON is ~~ 93 AKI or (RON+MON)/2 as we use in the US and ~~ 91 AKI for minum permissible grade.

It's true the car will run on 91 due to anti knock sensors but what do you think the EMC does when it sense knock ? What it does will definitely impact performance.

Further, the nominal value for octaine is based on atmospheric conditions that are nearly ideal (altitude: sea-level, humidity: moderate (don't remember the value), and tempature: moderate (don't remember)) so the higer the altitude, the lower the humidity, and the higher the tempature all increase the octane required.

So, where did you get your info about octane rating required for performance of an M5 ?

Brutus

SWP · 6th January 2006, 23:47

I just buy Premium gas from my nearby Shell station. Car seems to run just fine.

NobleM400 · 7th January 2006, 01:23

Quote:

Originally Posted by brutus

I don't think so or BMW wouldn't have put in the Euro English manual:

"> The engine of your BMW M5 is rated to run on: Super Plus/premium plus fuel, octane number 98 RON. Fill up with fuel of this grade whenever possible, so that hte niminal performance and fuel consumption values are achieved."

And: "> The minum permissible grade is: Premium-grade unleaded fuel, octane number 95 RON."

Don't have my US manual handy but 98 RON is ~~ 93 AKI or (RON+MON)/2 as we use in the US and ~~ 91 AKI for minum permissible grade.

It's true the car will run on 91 due to anti knock sensors but what do you think the EMC does when it sense knock ? What it does will definitely impact performance.

Further, the nominal value for octaine is based on atmospheric conditions that are nearly ideal (altitude: sea-level, humidity: moderate (don't remember the value), and tempature: moderate (don't remember)) so the higer the altitude, the lower the humidity, and the higher the tempature all increase the octane required.

So, where did you get your info about octane rating required for performance of an M5 ?

Brutus

Here's a handy chart on RON/PON conversion:

http://www.btinternet.com/~madmole/R...RONMONPON.html

98 RON = 94 PON
95 RPM = 91 PON

richhaywood:

Got the file. Wow, 19mb.

Anyhow, it's rotated, cropped, resized, and attached here. If anyone needs it bigger, just let me know.

richhaywood · 8th January 2006, 22:21

thanks for editing the pic NobleM400