W140 S500 Octane Grade

[television]

Further to grobers good post, do not drive the car hard on 91 ron fuel

 

[Raja Taimoor]

What I could gather from the learned members' views is that if it's just the RON then at least 95 is recommended.
But what about the average of the RON and MON e.g. an octane 91 means an average of 96 RON and 86 MON. Is this average rating acceptable to the W 140 S500?

 

[television]

As I see it the rating in Canada and the USA is our 91-92 ron is equal to mon 82-83
Esso super is 95 ron or 85-86 mon

Super plus in GB, Germany 98 ron is 88-90 mon

 

[ahockley]

I get significant differences in fuel consumption with different types of fuel in my 98 CL500. Best consumption is with the very high octane ones - about 5% difference between cheapest Tesco and Aral 100 Ultimate (which is actually98 I think). On my last long fast run using Aral 100 and speeds consistently over 100mph where legal, I got 27mpg average between Frankfurt and Ipswich UK which I think is pretty reasonable.

 

[Supercharged]

So............using a higher Octane grade fuel would increase fuel consumption ? What about around town ? would you see any difference ?

 

[Alex M Grieve]

So............using a higher Octane grade fuel would increase fuel consumption ? What about around town ? would you see any difference ?

"If all else was equal" then higher octane fuel should reduce consumption (less required to achieve the same effect).

Once you add the human factor - it goes faster, so I will drive it faster - then more fuel, not less will be used. But by then of course "all else is no longer equal".

Same is true of tuning (and probably chipping/mapping) - given extra performance, people will enjoy it and that will have an adverse effect on economy.

 

[television]

"If all else was equal" then higher octane fuel should reduce consumption (less required to achieve the same effect).

Once you add the human factor - it goes faster, so I will drive it faster - then more fuel, not less will be used. But by then of course "all else is no longer equal".

Same is true of tuning (and probably chipping/mapping) - given extra performance, people will enjoy it and that will have an adverse effect on economy.

Not true Alex, it is mainly the compression that dictates this though there are other things. There can be no benefit in using 98 ron fuel in a car that is designed to run on 95 ron, you cannot have more than 100% combustion.

I have tried the odd tank of super but no difference at all, it could be even worse as others have said.

If you chip the car petrol, then you are forced to use the higher octane fuel, but chipping petrols is not worth it