Why 97 RON fuel?
Discussion
So I've just had to fill up the car with 97 Ron petrol, again. BP not so ultimate in fact.
So why in the UK are we given 97 rather than 98 RON fuel. After all most high spec engines require 98 RON, the fuel companies must know this and yet don't in the majority supply it.
Well in the UK at least, because on the continent the fuel is usually 98 or even more as a matter of course. And this is the same suppliers.
Anyone know why this is and what can be done to change things?
So why in the UK are we given 97 rather than 98 RON fuel. After all most high spec engines require 98 RON, the fuel companies must know this and yet don't in the majority supply it.
Well in the UK at least, because on the continent the fuel is usually 98 or even more as a matter of course. And this is the same suppliers.
Anyone know why this is and what can be done to change things?
Ah maybe I wasn't clear. Its not I'm not happy with it (I'm not) but its that 97 RON isn't one thing or the other?
It doesn't fit the engine specs of most manufacturers higher end engines and, oddly is only offered to the brits while on the continent the higher 98 and 99 rons are offered as standard.
Don't see why that should be the case. The fuel companies know the engine specs, they know what the offer elsewhere so who is failing?
It doesn't fit the engine specs of most manufacturers higher end engines and, oddly is only offered to the brits while on the continent the higher 98 and 99 rons are offered as standard.
Don't see why that should be the case. The fuel companies know the engine specs, they know what the offer elsewhere so who is failing?
Mikeyboy said:
Ah maybe I wasn't clear. Its not I'm not happy with it (I'm not) but its that 97 RON isn't one thing or the other?
It doesn't fit the engine specs of most manufacturers higher end engines and, oddly is only offered to the brits while on the continent the higher 98 and 99 rons are offered as standard.
Don't see why that should be the case. The fuel companies know the engine specs, they know what the offer elsewhere so who is failing?
The Yanks get a lot less. It doesn't fit the engine specs of most manufacturers higher end engines and, oddly is only offered to the brits while on the continent the higher 98 and 99 rons are offered as standard.
Don't see why that should be the case. The fuel companies know the engine specs, they know what the offer elsewhere so who is failing?
The Black Duke said:
Mikeyboy said:
Ah maybe I wasn't clear. Its not I'm not happy with it (I'm not) but its that 97 RON isn't one thing or the other?
It doesn't fit the engine specs of most manufacturers higher end engines and, oddly is only offered to the brits while on the continent the higher 98 and 99 rons are offered as standard.
Don't see why that should be the case. The fuel companies know the engine specs, they know what the offer elsewhere so who is failing?
The Yanks get a lot less. It doesn't fit the engine specs of most manufacturers higher end engines and, oddly is only offered to the brits while on the continent the higher 98 and 99 rons are offered as standard.
Don't see why that should be the case. The fuel companies know the engine specs, they know what the offer elsewhere so who is failing?
I am pretty sure that all cars sold in Europe have to be able to run on 'normal' unleaded without problem. As a result, in principle, you should be able to run your Ferrari/Porsche etc. all day long on the standard stuff.
Given that the majority of car users will use the lower cost stuff it isn't really surprising that most petrol stations market to them.
Just got some more info from Wikipedia. No Citation though so not sure of the accuracy.
Generally, octane ratings are higher in Europe than they are in North America and most other parts of the world. This is especially true when comparing the lowest available octane level in each country. In many parts of Europe, 95 RON (90-91 AKI) is the minimum available standard, with 97/98 RON being higher specification (being called Super Unleaded). The higher rating seen in Europe is an artifact of a different underlying measuring procedure. In most countries (including all of Europe and Australia) the "headline" octane that would be shown on the pump is the RON, but in Canada, the United States and some other countries the headline number is the average of the RON and the MON, sometimes called the Anti-Knock Index (AKI), Road Octane Number (RdON), Pump Octane Number (PON), or (R+M)/2. Because of the 8 to 10 point difference noted above, this means that the octane in the United States will be about 4 to 5 points lower than the same fuel elsewhere: 87 octane fuel, the "regular" gasoline in Canada and the US, would be 91-92 in Europe. However most European pumps deliver 95 (RON) as "regular", equivalent to 90–91 US AKI=(R+M)/2, and deliver 98, 99 or 100 (RON) (93-94 AKI) labeled as Super Unleaded - thus regular petrol sold in much of Europe corresponds to premium sold in the United States.
Generally, octane ratings are higher in Europe than they are in North America and most other parts of the world. This is especially true when comparing the lowest available octane level in each country. In many parts of Europe, 95 RON (90-91 AKI) is the minimum available standard, with 97/98 RON being higher specification (being called Super Unleaded). The higher rating seen in Europe is an artifact of a different underlying measuring procedure. In most countries (including all of Europe and Australia) the "headline" octane that would be shown on the pump is the RON, but in Canada, the United States and some other countries the headline number is the average of the RON and the MON, sometimes called the Anti-Knock Index (AKI), Road Octane Number (RdON), Pump Octane Number (PON), or (R+M)/2. Because of the 8 to 10 point difference noted above, this means that the octane in the United States will be about 4 to 5 points lower than the same fuel elsewhere: 87 octane fuel, the "regular" gasoline in Canada and the US, would be 91-92 in Europe. However most European pumps deliver 95 (RON) as "regular", equivalent to 90–91 US AKI=(R+M)/2, and deliver 98, 99 or 100 (RON) (93-94 AKI) labeled as Super Unleaded - thus regular petrol sold in much of Europe corresponds to premium sold in the United States.
Its a complicated business, for turbo cars you want stability which Tesco 99 and Shell Optimax / V power whatever its called offer, this is easily measured if your in a tuned car with knock detection, these two UK fuels work well. BP Ultimate is crap for turbos it doesn't allow the ignition advance that the tesco or sheel allows, but apparently (so I've read -don't know if true) the BP stuff has a higher calorific value so the burn is supposed to provide more energy 
Generally speaking the calorific value of the fuel is inversely related to its octane rating. Longer-chain hydrocarbons have higher calorific value but lower octane rating - see LPG (high octane, low calorific value) at one end of the scale and diesel (high calorific value, ruinously low octane) at the other. Many octane-boosting additives are hydrocarbon molecules with added oxygen which also gives them a low calorific value - in effect they are partially oxidised before they even get near your engine.
Mattt said:
You can get 102RON in some stations in the UK 
I'd love to see if I could notice the difference with this stuff.So is everyone saying then that because the UK standard is 97 then thats what the fuel suppliers supply?
Still seems odd to me that there is anational standard that is lower than the standard that the engine designers prefer the ECU's to run the engines on.
So is this the fault of engine manufacturers or just stingy oil companies?
I have had several turbocharged Saab's, Shell Optimax makes a huge difference in these cars, and is noted on a lot of the Saab forums. In my current supercharged car I feel no noticeable difference. I also have a 1991 Suzuki Vitara, that needs 98 RON, otherwise it coughs and splutters like a good un, and my Subaru forester shows a remarkable difference with 98 RON compared to 95 or 97, both of these have stickers saying 98 RON only. IIRC the book for the Saab said it would work from 92Ron all the way up to LPG
Edited by Cecil on Monday 29th March 21:43
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