95RON or 98RON petrol in GTI mk6?

[flappa]

Ah, the benefits of a fuel Card.

With my Nissan Patrol which runs quite happily on 91 RON, I could tell the difference quite easily between BP, Shell and Caltex Fuels and from 91 to 95RON fuels. I could tell no difference between 98RON to warrant paying the extra.

However, with the GTI , 98 as much as possible with BP as preference

[Diesel_vert]

Fuel standards in Europe (along with most aspects of economic activity) are determined by the Comité Européen de Normalisation (CEN) or European Committee for Standardization. And the relevant standard for petrol or gasoline is Norme Européenne 228 ( EN 228 ) or European Standard 228. Diesel is covered by EN 590. As far as I'm aware, these standards are not legally binding by themselves, but most Member States (UK, France, Germany, etc.) adopt these standards as part of their legislation, which then become law (European bureaucracy at its finest).

In the UK, France and Germany most petrol is sold as 95 (regular unleaded/sans plomb 95/Superbenzin) and 98 (super unleaded/sans plomb 98/Super Plus Benzin). But weirdly, in Germany, 91 (Normalbenzin) is also freely available, though I believe it's slowly being phased out.

In regards to quality, comparing EN 228 and the Fuel Quality Standards Act 2000, one notable difference is the sulphur content. From 1 January 2009, petrol conforming to EN 228 is limited to 10 mg/kg (10 ppm) and designated as "sulphur free". Australia in comparison has a limit of 50 mg/kg (50 ppm) for 95 & 98, and a whopping 150 mg/kg (150 ppm) for 91. Sulphur content is an issue particularly for direct injection engines, because DI engines can operate under "lean-burn" conditions which reduces fuel consumption. "Lean-burn" conditions create excessive nitrogen oxide (NOx), one of the regulated pollutants. This is dealt with by using three-way catalysts (TWC) which, very simply, "stores" as much NOx as possible until the engine momentarily runs rich, providing excess fuel which eventually converts it to harmless nitrogen. But as sulphur compounds are chemically similar to NOx, they compete for storage space, quickly "filling up" the catalyst, decreasing its efficiency and inducing frequent "rich" runs, thus increasing fuel consumption - one reason why you'll never see the full economic benefits of lean-burn technology here, and probably why the SIDI engine in the Commodore isn't as fuel efficient as it should be (amongst other reasons).

Research octane number (RON) and motor octane number (MON) for are identical for both standards, set at a minimum of 95 and 85 respectively. In Sydney, 98 is only 5 cents dearer than 95, so totally worth it IMO. Though I noticed at volkswagen.de that the new Golf R can use Superbenzin 95 RON, but to achieve maximum performance Super Plus Benzin 98 RON is required. But nothing is mentioned for the GTI, other than to use Superbenzin 95 RON.

And in the latest version EN 228:2008 (superseding EN 228:2004), "Premium unleaded petrol” becomes “unleaded petrol”, probably because 95 and 98 have been the main sellers in the EU for some time. I think this is what Dear Moderator is referring to - just a wording issue, nothing more. Though it is also noted that Member States "may decide to continue to permit the marketing of unleaded regular grade", with a minimum RON and MON of 91 and 81 respectively (likewise in Australia). Hmmm, a get-out clause for the less well off Member States perhaps...

So in terms of engine performance our fuels are comparable to European fuels, but in terms of environmental performance we still have some catching up to do. And for other lurkers with European cars considering using 91 instead of 95, for goodness sake don't! There's a reason why it's so cheap!

[Coaster]

I would agree with that if I there was not difference between Shells 95 and BPs 95
car runs very different (thats why I try not to use Shell)

Would there be a difference? I know in Perth there is only one refinery, so my uneducated guess is each brand markets the same fuel (i.e. Caltex Vortex, BP Ultimate are exactly the same).

Either way, I don't use my car much so 98 is within my budget.

[jj77]

I know this is out of this thread's topic but I didn't want to open a new thread...
My car is MKVI 118TSI and came from the dealer with a tank of 95RON (not sure about the brand).
This afternoon, I finally managed to finish up the fuel came from the dealer - hit the redline and driving range was less than 40km. Then, I filled up my new car for the first time since taking delivery using BP Ultimate.

May be this is a weird coincident or I am imagining things but I've noticed that the engine sounds more "coarse" than before I filled up my car with BP Ultimate (especially when idling at the traffic lights) - and also 1st to 2nd to 3rd gear.

May be just a bad batch of fuel... will try a different BP servo next round - i hope one batch of bad fuel won't do much damage to my precious Golf and I hope my (perhaps imaginary coarse engine sound) is not permanent.
Any thoughts or comments?

Cheers,
J

[Maverick]

I know this is out of this thread's topic but I didn't want to open a new thread...
My car is MKVI 118TSI and came from the dealer with a tank of 95RON (not sure about the brand).
This afternoon, I finally managed to finish up the fuel came from the dealer - hit the redline and driving range was less than 40km. Then, I filled up my new car for the first time since taking delivery using BP Ultimate.

May be this is a weird coincident or I am imagining things but I've noticed that the engine sounds more "coarse" than before I filled up my car with BP Ultimate (especially when idling at the traffic lights) - and also 1st to 2nd to 3rd gear.

May be just a bad batch of fuel... will try a different BP servo next round - i hope one batch of bad fuel won't do much damage to my precious Golf and I hope my (perhaps imaginary coarse engine sound) is not permanent.
Any thoughts or comments?

Cheers,
J

Maybe your engine is making more power now and/or loosening up.

If you're really worried take it in to get it looked at but it sounds normal.

Sent from my Nexus One using Tapatalk

[jj77]

Thanks, Maverick.
It's good to know that it sounds normal.
As you mentioned, perhaps the engine is making more power - many members in other petrol related thread mentioned that BP Ultimate and Mobil generate more power and produce better performance.

Before your response to my post, I didn't think of the coarse sound (not really coarse but sound is more obvious than before kind of coarse) as more power or engine being loosening up

Cheers,
J

[prise]

...Australia in comparison has a limit of 50 mg/kg (50 ppm) for 95 & 98, and a whopping 150 mg/kg (150 ppm) for 91. ...

This is true, however I had an interesting chat with an engineer who works at the Melbourne Mobil refinery the other day and apparently 'most of the time' the sulphur content is a fraction of the 50 ppm spec as it is for a number of other Australian refineries but they will never advertise anything lower due to the risk of being prosecuted for false advertising if one batch fails to meet it. He said the main difference between brands of fuel with the same octane rating was the additives as in each capital city the major brands often take their base stock from another brands refinery and mix the additives at the rack. This means that the sulphur content and base stock mix will vary between capital cities for the same brand.

[Cossor]

quality, comparing EN 228 and the Fuel Quality Standards Act 2000, one notable difference is the sulphur content. From 1 January 2009, petrol conforming to EN 228 is limited to 10 mg/kg (10 ppm) and designated as "sulphur free". Australia in comparison has a limit of 50 mg/kg (50 ppm) for 95 & 98, and a whopping 150 mg/kg (150 ppm) for 91. Sulphur content is an issue particularly for direct injection engines, because DI engines can operate under "lean-burn" conditions which reduces fuel consumption. "Lean-burn" conditions create excessive nitrogen oxide (NOx), one of the regulated pollutants. This is dealt with by using three-way catalysts (TWC) which, very simply, "stores" as much NOx as possible until the engine momentarily runs rich, providing excess fuel which eventually converts it to harmless nitrogen. But as sulphur compounds are chemically similar to NOx, they compete for storage space, quickly "filling up" the catalyst, decreasing its efficiency and inducing frequent "rich" runs, thus increasing fuel consumption - one reason why you'll never see the full economic benefits of lean-burn technology here, and probably why the SIDI engine in the Commodore isn't as fuel efficient as it should be (amongst other reasons).

And perhaps causing reported problems of Lambda probe failures?