Fuel for the R?

[Poached]

Love the AMG 5.5 engine, what a beast. But I think I would be putting the ol' premium in that! Did your dad change from an AM, V8 as well? I just love V8's in general I guess 

Yeah its a monster, it quite happily spins its wheels up at 70 if you give it the beans, and yes changed from the Vantage S. Needed something more useable :')

Drives a CLS63/Aston Martin and complains about the difference in price between regular and super unleaded...

They drink fuel, he's not bothered about mpg and i challenge nearly everyone to try and beat it so the marginal power increase is irrelevant. It all comes down to how much value you put on the increases, clearly you place more on it than I or my father does

Charv

The benefits are well established particularly on cars that can adapt the timing advance such as the Golf GTI or R. If you plan on remapping the car, better fuel will give the tuner a bigger opportunity to safely increase the power.

My comment regarding the fuel was just a bit of perspective. The cost difference amounts to a small proportion of the total cost of ownership of those cars. Often people forget about other costs because they readily see the cost of filling up rather than servicing and depreciation for example.

[charv94]

 
My comment regarding the fuel was just a bit of perspective. The cost difference amounts to a small proportion of the total cost of ownership of those cars. Often people forget about other costs because they readily see the cost of filling up rather than servicing and depreciation for example.
[/quote]

I see the point, £10 a tank say on a 100k car is nothing and when its compared to maybe £1000 minor service it seems silly to question it. its just psychologically, paying under £100 a tank is far better that over that. its why fuel is 105.99, it just sounds better than 106. I get what you mean and will take it into account when i am filling up come april.

[Exonian]

I wonder how many of the 50p lease R's will get run on 98.

In fact I wouldn't mind betting a hell of a lot of them get run on plain Super 97 RON.
Not just the leased cars either.

[monkeyhanger]

I wonder how many of the 50p lease R's will get run on 98.

In fact I wouldn't mind betting a hell of a lot of them get run on plain Super 97 RON.
Not just the leased cars either.

Is there anything wrong with RON97 (like Esso has)? Do VW state to use 98 just because it is smack in the middle of 97/98/99 Super unleaded variants you see around in the UK? On paper at least 97 has to be better than 95 as it'll resist pinking appreciably better than 95 under the higher compression ratios of cars set up for 98, would the timing be altered at all using 97 rather than 98? Conversely, does anyone see any benefit/harm in using 99 over 98? As long as it ignites easy enough under spark after compression  for full combustion then I can't see any gains/losses there either (although with premium fuel there is the expectation of better detergents to keep the engine clean).

Some people naively believe that the RON rating is a measuure of potency/calorific content.

If all I could get my hands on was 97, I wouldn't sweat it. Going by the petrol prices daily email I get, Esso 97 and Tesco 99 are a good 3p a litre cheaper than the Shell/BP alternative (although Shell points do redress some of that balance)

[matchboy]

On the odd occasion I've pulled up at a pump that doesn't have the fancy stuff and I've put regular unleaded in, I can't say I've noticed the difference in terms of power or consumption.  That doesn't mean there isn't any, I just haven't noticed any.  But IMO if you've spent all that cash on an R then you might as well pay a few pence more per litre and use 98/99.  My long term average after 4k miles is 27.1, which is pretty decent given I have a penchant for Race & Sport when the opportunity arises 

[corgi]

It will only make a difference if the ecu detects detonation (pinking) and backs the timing off. Assuming it does, then you are likely to see approaching 10% less peak power and torque but putting 100 RON fuel in were it available (like it is in, for example, Italy) will make absolutely no difference because the ecu will not advance the timing in this case.

It is a false economy to use 95RON in a car tune to use 98RON for the reasons discussed above...

I certainly notice the difference if I have to run my 911 on 95RON... throttle response and acceleration are definately affected as well as fuel consumption...

[itavaltalainen]

Is there anything wrong with RON97 (like Esso has)? Do VW state to use 98 just because it is smack in the middle of 97/98/99 Super unleaded variants you see around in the UK?

No, it's simply because premium petrol in most of EU is 98 RON (with exception of higher octane versions that have come on market in last few years). There is no 97 RON in Germany at all.... it's either 95, 98 or whatever higher number Shell, BP and others sell. 97 RON is very much a UK thing, I haven't seen it elsewhere (certainly not any of the German speaking countries, Nordics or Central Europe).
There is also no difference in ECU between EU market cars.... all fuel is EN xxxx anyway.