My fabia has a 1.4 16v engine and i have always run on (supermarket) unleaded. According to the computer, i have been getting a reasonable 43 mpg on my regular commute to work. I have filled up the last 2 tanks with super unleaded (sainsburys) and doing the same commute have only been getting 41mpg.

Has anyone else experienced this? i am beginning to feel suckered in by the hype and will probably go back to my usual fuel!

fuel consumption will go down/get worse as the colder weather comes upon us , so i wouldn't worry about it too much , just use your regular fuel and don't waste your money

An engine such as yours will produce less power using Super unleaded and you'll get worse economy because the ECU is not clever enough to adjust the fuelling according to fuel grade - as a rule of thumb if it's not a performance car you're wasting your money. Use 95 instead and you'll go faster.

If you don't believe me do a google search - it's all well documented.

I see Vw (and I suppose Skoda too) advise the use of SUL on the new FSI engines , even the 1.4 unit , does anyone know why this is?

The good book says that the 1.4 16v is (I think) the only engine that they suggest 98 RON (?) and say it CAN run on 95 RON (?). The other petrol engines suggest 95 RON (?) and they can run on 92 RON (?). (I put (?) because Im not sure as to the exact numbers.

I get better economy on the expensive stuff but as I put in this post (CLICKY) I drive like a grandad!

A standard ECU will only advance the timing as far as 95 RON can handle without pinking. Therefore putting on 97 RON or higher will not make any difference to performance or MPG. Remapping the ECU will set up the ECU to allow grades of up to about 100 RON to be used (where available). It'll just use the knock sensors to push the ignition timing that bit further. You'll have more torque etc due to this and will only get more MPG if you drive the same as before. If you cane it and make use of the extra poke then forget extra MPG.

I've chipped 2 cars so far (both BMW's running OBDI ECU's) and had this effect.

When I used performance fuel in my very old favorit I got worse mpg because I was driving it harder look for a diffrence.

There wasn't one.

The good book says that the 1.4 16v is (I think) the only engine that they suggest 98 RON (?) and say it CAN run on 95 RON (?). The other petrol engines suggest 95 RON (?) and they can run on 92 RON (?). (I put (?) because Im not sure as to the exact numbers.

I get better economy on the expensive stuff but as I put in this post (CLICKY) I drive like a grandad!

Yes the 1.4 16v is recommended that 98 is used in preferance to 95 octanes... !!!

Yes the 1.4 16v is recommended that 98 is used in preferance to 95 octanes... !!!

Yay! I was right :P

All this talk about petrol has got me feeling thirsty...

Thanks for the explaination, i will go back to the supermarket cheap juice!