Hi,

Does anyone please know in layman's terms what benefits are to be had from using premium unleaded instead of unleaded in a S/C?

Also, is there really any benefit to be had from buying 'branded' petrol rather than supermarket fuel?

Thanks...

The warm glow of knowing you have done your bit for the economy  2008 MY Supercharged
Rimini Red / Jet
four zone climate
remote park heater
and no ugly kid windows.
magnus satis quod turpis satis

On first read, I thought you'd said environment... then when I woke up I read you correctly!!

I run mine on Shell V-Power, but I pay for my fuel out of my company which means it's pre-tax, so practically LPG prices at the moment. I use Rev with a Wi-fi OBD port reader and there is a marginal improvement in engine performance on premium fuels, but on a near 3 ton SC it's not noticeable. If you are gonna rag the hell out of the car (lots of high RPMs for a sustained period of time) then you'd benefit from the safety of better octane values. Also if you have tuned the car for premium fuels you'll get better performance out of them.

It's important to note that the RR ECU adapts to a lot of inputs, and it adapts pretty fast. I've found it's updated the long term fuel trims within around 20 miles of driving after making engine changes. That means it's monitoring what it's capable of and keeps trying to get the best performance for the preprogrammed stoichiometric ratio (air/fuel mix, 12.4:1 for performance and around 15:1 for economy). 
07 Supercharged - Still breaking her in!

Boot soundproofing part 1 - http://www.fullfatrr.com/forum/topic15612.html
Custom exhaust - http://www.fullfatrr.com/forum/topic15296.html
18" wheels for Brembo equipped cars - http://www.fullfatrr.com/forum/topic15052.html

Thanks.

We don't drive the car hard at all (in fact, have barely driven it in the 3.5 weeks since getting it pending resolving a few points with the selling garage... it's a nice looking ornament though... so says my wife whose car it is/ Ha...

The car has not ben modified in any way... just wondered if it was better for the longevity of the engine (and maybe marginally better fuel consumption) if premium was used.

Pretty moot point where I am. I would put it on regular and not premium though. But a clean good quality regular. The NAS spec cars are "set-up" for pretty low octane fuel as the American market still seems to have that quite a lot. Not sure if the EU cars run on the same fuel maps (I expect them to). MY 2010 5.0 SC Galway green and sand interior!!
Have the Faultmate MSV2 Extreme to be tinkering with the settings etc. !!

According to RAVE they run on similar maps. The RR is supposed to be able to go anywhere on any crappy fuel, although I wouldn't want to test that ... 
07 Supercharged - Still breaking her in!

Boot soundproofing part 1 - http://www.fullfatrr.com/forum/topic15612.html
Custom exhaust - http://www.fullfatrr.com/forum/topic15296.html
18" wheels for Brembo equipped cars - http://www.fullfatrr.com/forum/topic15052.html

The NAS ones had a lower output as well IIRC

Stick with a normal unleaded and save the pennies for the repair bills instead as it wont make any difference to a woman or the long term of the engine really as long as every now and again it gets a tank or two of nice Vpower it should keep the internals clean enough! FFRR MY06 facelift With TDV8 Alloys Zeros/ATR's
Mantec Sump Guard, Rigid Load liner, MY10 BT upgrade.

It runs fine on crap fuel although I do run injector cleaner from time to time, since I don't know what "additives" have been added at the fuel station  MY 2010 5.0 SC Galway green and sand interior!!
Have the Faultmate MSV2 Extreme to be tinkering with the settings etc. !!

Repair bills! Come on! Is there not a clue in the title [Range Rover] aka Tonka toys !

As for the sexist joke... well

Its all jest  FFRR MY06 facelift With TDV8 Alloys Zeros/ATR's
Mantec Sump Guard, Rigid Load liner, MY10 BT upgrade.

Last edited by pld118 on 1st May 2013 3:38pm. Edited 1 time in total

Gotta keep these House Frau's in check and semi happy these days! The days of chaining them to the rayburn are long gone


 FFRR MY06 facelift With TDV8 Alloys Zeros/ATR's
Mantec Sump Guard, Rigid Load liner, MY10 BT upgrade.