Mkv's only running on super unleaded??

[bruin3182]

Having read Clarkson's review he states that the new FSi engine only runs on super unleaded...98 ron +
Has anyone tried normal unleaded 94/95 ron? Is supermarket grade fuel any good?

If so how's it run... The dealership (INCHCAPE) say that if I use normal unleaded the engine management system will malfunction!!!

Can I mix the two types, say fill up with super every third tank??

What do you owners reckon?

Also how do they use oil? - hopefully not like Mazda RX8's (half litre every two weeks)!

Fuel knowlege please!

[GTiMK5]

My dealer told me it didnt matter what fuel was used in the car and according to the car spec it will run on 95ron. However, I only use optimax in mine and dont intend putting any other fuel in unless it is an emergency.

Optimax will give optimum performance and also return better mpg. I would not use supermarket fuels as they put less additives in their fuels, hence the cheaper price, this can over time cause engine damage. However, I believe Tesco have a new 99ron product at some garages which in theory should be better than optimax and is also cheaper but I am still not convinced.

As for the oil, mine has not used any in 2000 miles and I have heard similar from others.

[Soarerv8]

Have been using any fuel in mine from Supermarket special through to Optimax. Cannot see any difference in performance or economy from either.

Have also not used any oil at all in the last couple of months but mileage is still pretty low at around 1000 miles (only really use it as a toy at weekends so spends most of the week in the garage).

Am going to get the brakes checked over shortly, they don't feel able to shed speed in quite the way I would expect and even my big "old man" style BMW is more willing to stop.

Adrian

[GTiMK5]

Have been using any fuel in mine from Supermarket special through to Optimax. Cannot see any difference in performance or economy from either.

You are the first person that I has not noticed a difference in economy using both types of fuel, the FSI engine is designed to provide optimum economy with 98ron fuel. When the engine is new it has to get used to the type of fuel used before you start getting optimum performance but by using different types regularly the engine is not going to.

I would also strongly advise against using supermarket fuel on a regular basis as there have been cases of engine damage from this.

You will hear people say that they get their fuel from the big names such as Shell, BP etc which is true, but it is to do with the additives and cleaners that they add to it after, they use less than Shell and BP etc, hence the reason they are able to sell it cheaper. In the long run though if it goes on to cause engine damage etc you will end up forking out a lot more money than the couple of pence you have saved on each litre of fuel.

[Soarerv8]

Have been using any fuel in mine from Supermarket special through to Optimax. Cannot see any difference in performance or economy from either.

I would also strongly advise against using supermarket fuel on a regular basis as there have been cases of engine damage from this.
 

Thanks for the advice, what sort ofd problems could I expect and over what mileage?

[Dizzie]

optimax looses it's octane over time. I've found the car runs a lot better as soon as I leave the forecourt, but after a day or so it's back to normal. I've been using tesco's super (97) for months now and the engine performs awesomely.

[dutch]

Shell garages do optimax with is RON98 (better than BP Ultimate)

God knows why they don't advertise it as such ... I only found out by looking at their website

[dimma02]

HI
Again, 95RON is ok for the GOLF GTI, a knock sensor retards the timing preventing 'pinking'. You will loose a little BHP and Torque and thats it, MPG not really!!! VW tested the car to run on low sulpor fuel which we do not have (here in Ireland anyhow!! or 97RON come to think about it, well harder to get) but tested it on 95RON, They would not publish the spec as 95RON if it could not run on this fuel, end of story,, Running on 97Ron means of course better efficency and lower engine temps but it will run just as well, save a few quid on 95RON,,,No damage can happen to the engine as the ECU will detect the detenation (timing) and retard as nessary...

Any views, on this.. Cheers Focus RS owner for now but GTI on the way!!  Ireland.

[Mr Blonde]

Dimma is correct here and I would go one further by saying 'may' rather than 'will'.

Its not a dead cert by any means that 95 will produce knock in anything other than extreme conditions. Very hot weather, maximum throttle loadings expecially at low revs would certainly do it. My bet would be that driving normally would not do it.

Do what? The car can't knock - the sensor will simply retard the timing. At this point, you are sacrificing hp (by forcing the management system to use a less advantageous map).

The is no more 'power' locked away in 98ron than 95ron. It just resists detonation better. This resistance allows more advanced timing etc etc.