V Power

[ainarssems]

You can tell the ECU has changed fuel maps onto a lower profile to suit the fuel.

Just a little explanation. ECU does not change fuel maps and does not have ability to change maps on it's own. It's what tuners do. Fuel trim is changed on demand depending on feedback from O2 sensors. ECU also stores learned value by how many % fuel trim should be adjusted in idle and part throttle. This ids further trimmed on the fly depending on conditions

Where RON comes in is if it is too low and engine starts knocking it retards ignition timing to prevent knocking. This also happens on the fly depending on feedback from knock sensors. If you fill with good fuel again and it is not knocking it does not retard ignition any more. This depends also on carbon buildup in compression chamber, spark plugs, vacuum leaks and other factors. Also if knock sensor bolts are over-tightened knock reading will be higher or if you have something loose banging on the engine. I have logged my S8 and it almost never retards ignition with V-Power, with regular 95 it only does it occasionally under heavy load. M8tes 3.7 on the other hand retards ignition with 95 on the slightest acceleration and on 98 it still retards on heavier acceleration even if 3.7 have lower compression.

[Adrian E]

We always used to look at maps in 3d but figured for lay folk it's easier to understand talking in 2d terms

[sarg]

used the 5p voucher at Shell Rugby tonight, no problems, they'd clearly had a few waved under their noses and knew what to do with it

[The_Laird]

Originally Posted by sarg

used the 5p voucher at Shell Rugby tonight, no problems, they'd clearly had a few waved under their noses and knew what to do with it

I have a few suggestions!

[tintin]

I also use this all the time - http://www.petrolprices.com, especially if I'm in an unfamiliar territory.

[Norretal]

Well, after my first venture into using a higher grade of petrol I have to say I'm most impressed. I've driven the car for 7+ years and have always been happy with it but the introduction of Shell's finest has improved (or seemed to) my driving experience even further. I'd read quite a bit about it on here beforehand so not sure how much I've been inadvertantly influenced by that but I feel the responsiveness and smoothness of the engine is better than at any other time I've driven the car. It's early days yet and I'd like to get a long run in it under my belt but early signs are promising............but then again, everyone else on here already knew what difference it makes.

The improvements to the steering (bushes, arms etc), brakes and change of wheels has transformed the car and "feeding it" properly has made topped it all off nicely.......now to enjoy using it a bit more

[The_Laird]

My first tank full of Shell's finest (compared to my usual BP finest) returned exactly the same mpg, and I'm now on my second tank full. I'm going to use Shell for 3 fill-ups and then report on the results.

Those comparing 'cooking fuel' with the higher octane stuff are bound to notice an improvement, so I hope my little test will compare 'apples with apples'.

[briang9]

Originally Posted by The_Laird

My first tank full of Shell's finest (compared to my usual BP finest) returned exactly the same mpg, and I'm now on my second tank full. I'm going to use Shell for 3 fill-ups and then report on the results.

Those comparing 'cooking fuel' with the higher octane stuff are bound to notice an improvement, so I hope my little test will compare 'apples with apples'.

Is there any difference in how the car "feels" bewteen the two Jim? My MPG actually went down with the V Power but thats down to more spirited driving

[The_Laird]

I'm really not sure about how the car 'feels', to be honest. If there is a difference, it's not much.

When I did a longer test, a good few months/years ago, between 'normal' BP and BP Ultimate, my conclusion was that there was definitelty an improvement in mpg, but not enough to compensate for the additioanl cost.

I still use the 'good stuff' because the performance is better than 'normal' fuel and I think it's probably better for the engine. A little extra mpg is a bit of a bonus that doesn't make me grudge the additional cost.

[Adrian E]

New offer from Shell arrived in my inbox this afternoon - fill up Friday or Saturday with more than £30 of Nitro+ and they'll give you a free Sky Sports/Now TV day pass which is valid for a week (only for a 24hr period, but handily coinciding with the Monaco GP)

There's a list on their web site of the number of vouchers available at participating sites - there's 300 at my local so can't see them running out in a hurry! Must use up my £2.50 off vouchers too lol