just tried googling it. I can only find info on morrisons 95ron fuel. that aint going anywhere near my car
speaking to an old chap last week , he was telling me it's all a big con regarding unleaded and super.
He uses normal 95ron in all his cars. He's currently driving a rs5 his last car was a r8 . Shall I take his words with a pinch of salt or is he right.
The TFSI has been as standard designed and mapped to run on 98 ron or above, anything less like 95 ron will cause combustion issues as the burn front will be wrong (either the fuel wont burn quick enough to keep up with the piston movement or you will get pre-ignition burn before the piston has moved), the ECU is able to compensate for this by adapting the map that it uses to avoid 'knocking' this will involve pulling timing or other parameters to ensure that the fuel burns evenly and in time with the piston movement.
This will result in a loss of power across the rev range and can also increase fuel consumption (as you have to use more throttle to achieve the same power levels and therefore same level of acceleration).
In summary your engine will run on standard 95 ron fuel but you wont have the power you should, thats what VW do to make sure they can sell there cars in all markets some which have far poorer quality fuel than the UK. as janner has mentioned mapped cars are different, the principal is that the head room VW built into the map is removed to allow greater performance but this is the head room generally used for inconsistent fuel so most mapped or tuned cars will need to run exclusively on higher octane fuel.
So the old chap isnt telling you the whole story I'm sure all his cars managed to run on 95 ron fuel but frankly if you are spending that much on a car especially a turbo charged RS5 its a bit pointless if you dont give it the higher octane fuel. The R8 I can imagine made no difference as its an older normally aspirated engine.
