I've had my CR TDI-170 Octavia vRS for about 4 months now and I've run it on standard diesel (usually supermarket) since new. It's been fine/brilliant etc and today going from Keighley to Leeds managed 54.6mpg, so everything seems fine!

I was going to switch to a Super Diesel next time at the pump to see what difference (if any) it makes but I have 2 questions;

1, Which Super Derv is recommended more than others? Shell/BP etc for the VAG Diesels?

2, How many miles/half-fill ups will I need to run on before I can really see if theres any difference in MPG/Performance etc? I'm guessing just sticking 1 tank in won't be enough to 'flush out' the older stuff and work its magic? Or will it?

What do you think?

I'm not expecting or needing miracles but would be interested to see on this car/engine and my driving style whether its worth the extra.

Also, for people that always recommend to use Super as it keeps the engine clean etc would sticking a few tanks in of Super every few months with standard in-between do the job of keeping it clear? Kinda like giving the engine a spring clean treat?

"Super DERV" usually claims to work by burning cleaner, which means a higher citane index. OTOH higher citane index means less power, which should actually make fuel economy worse.

Ref (2), how low do you run the tank before filling up? I normally run until about the low fuel light comes on (say 1 gallon left) and fill until the pump cuts off (say filling 10 gallons), so I'd be down to 1% "normal" in 2 fills. OTOH, if you fill at half-full, you'd still be at 6.25% "normal" after burning the same volume over 4 fills.

Edited 23 February, 200917 yr by KenONeill

Surely they can't make it less powerful and less MPG?

What would be the justification of its existance?

I switched to running mine on Shell V-Power diesel for the past 4 re-fuels and am struggling to notice much if any difference. I'm certainly not aware of any performance increase and if there has been a change (improvement) in the fuel economy, it's difficult to tell as the weather has got a lot milder in the past week and that probably makes as big, if not a bigger difference. Plus I've had a couple of long journeys in the past couple of weeks which has improved the average.

The only area I think I can tell any difference is that the engine seems a bit smoother.

I should add that for the most part, prior to using V-Power, I was using ordinary Shell diesel with an occasional supermarket re-fill when there was 5p off.

To sum up then, the jury's still out :confused:

Surely they can't make it less powerful and less MPG?

What would be the justification of its existance?

Never underestimate the placebo effect (it costs more, so it must be better). Also, as noted, it soots less, which may be desirable in certain applications (the very ones who are most likely to know why it doesn't work in any other way however).

I used V power for a few months and found that the car was less sooty and was a few miles per gallon more economical. The car didn't feel any more responsive though and when the cost of Derv went through the roof, I switched to normal but branded Diesel anhave stuck to it. I guess you have to try it and see if it works for you but don;t expect miracles from just one tankful of the stuff.

It's a waste of time and a great money maker for the garages. V. Power got me a lower MPG and no noticeable increase in power.

Feel free to buy it if you so desire as it's your money.

Well I'd run for 12 miles with my gauge saying I had 0 miles left so I pulled into a Shell Garage and put £30 of V-Power Derv in on the way home, purely as this pump was for V-Power Derv only and didn't have a queue!

Let's see how it goes!

I'm not expecting any difference TBH but as I've owned the car from new it might be worth using at least branded diesel as opposed to supermarket? Or do you think thats a waste too?

Use which ever fuel supplier makes the car run well and gives you good MPG.

Every engine has different needs and preferences.

I'd always use branded fuel; comes from knowing an Esso manager, who knew a lot of tanker drivers, who knew that whilst the base stock was the same, Esso got a different additive pack to BP, to Shell, to Texaco... when the tanker was loaded, and supermarket fuel is base stock with no additives!

Just use whatever is cheapest.

Some of the people who are saying supermarket derv is bad, should try some of the fuels used in other countries in europe and then see what they think of the supermarket fuel.

I tend to run shell derv extra, but that is currently the cheapest around for me.

I'm not saying it's actually bad; I'm saying you can buy better fuel for 1% more.

I normally use Tescos Satan Juice for mine. Filled it up today after 8 days on the same tank, with 25 miles left in it

Only 25? :eek:

Bring back BP Ultimate

Forget super derv... just buy some of this instead..

I can do you a really good deal on some..

As if snakes didn't slide easily enough without special oils!

I Just use normal Bp diesel with Millers addertive.

Only 25? :eek:

Oh go on then, suprise us........