I've run my 2010 vRS TSI on super since the day I got it - 77k miles so far..

Unfortunately I've had a bi tof a disagreement with my boss who would prefer that I used regular unleaded as its cheaper.

My view is that the car is designed for super (it says "super" on the fuel flap after all!) so will run better and give higher mpg on super given its higher octane rating. Some tank vs. tank comparisons using the mfd shows there is a mpg benefit but as you can imagine it's not entirely scientific.

Does anyone know of any proper empirical research done to compare the two?

I think they did a test like this on 5th gear from what i remember. They did conclude that a higher MPG was achieved but i cant rememebr if it offet the extra cost. TBH i have used super unleaded in preveious cas and could honestly not tell the difference. Its mainly phycological. Some cars are designed for it however and highly tuned cars respond better to the higher octane but a standard car would hardly feel any different. I had my scooby mapped for the higher octane fuel and therefore needed to use it but if a car can run on both i would defy anyone to be honest and say they could feel the extra power.

IMHO if you've access to good quality regular (95RON) from Shell et al then I'd use that.

If you've only got access to supermarkets then stick with super.

My non-empirical experience is that there is little difference in MPG between super and quality regular.

There is a little bit of degradation in mpg when using supermarket regular but a significant degradation in the driving experience. Supermarket regular makes my TFSI feel heavier and much less responsive. There is a little bit of that with quality regular but it's much less pronounced.

The main problem is that not all engines seem to respond to different fuels in the same way, something that is bound to happen since the engine management systems learn to a small degree and also there is going to be a certain amount of psychological input.

Yep, don't disagree with anything there. I *think* I can tell the difference in terms of the performance of the car but without a scientific/back to back test its impossible to know if this is real or just placebo, and I can remember that EVO did a test a few years ago on a Golf GTI (TFSI engine) that gave increased power with shell optimax (vpower) but I can't find anything around the mpg improvements.

In theory there should be a benefit, after all, higher octane = more bang hence less fuel required for the same performance but I can't find any research that backs this up.

I've pinged an email to Skoda customers services to see what they say - I'll post the answer here.

For some reason the 'super' referred to on the flap of the TSi also states 95 RON. I can only assume the label is printed for countries where 91 RON is standard and 95 RON is super.

There have been a few posts on here regarding this topic. I beleive that the TSI engine is happy with 95 RON but the TFSI prefers 98 RON. My manual states using fuel higher than 95 RON won't improve engine performance (2008 1.8 TSI). Not sure if this applies to the 2 litre engine though.

TFSI does fuel stratification (lean burn?) if you're running on super so any gains from using super might be much more pronounced on the TFSI than the TSI.

http://en.wikipedia.org/wiki/Turbo_fuel_stratified_injection

No idea if this right or not.

For some reason the 'super' referred to on the flap of the TSi also states 95 RON. I can only assume the label is printed for countries where 91 RON is standard and 95 RON is super.

It says 95 MINIMUM, but also says SUPER.

I take that to mean that the car is designed to be run on (recommended) Super, but can run on any fuel that has min 95 ron. Am i right?

95 with reduced performance IIRC

I find my 1.8T a little bit more drivable ?? Is that a word that applies, less pedal needed for slow manuvoures .... I think !!

The book says 95 RON should be used but petrol with higher RON can increase power and reduce consumption. As peak power is probably never used for more than a few seconds, is it worth it. I would be surprised on a daily drive if more than 100bhp is used.

I would be surprised if you could tell the difference but then the internet is full of 'experts' who will say it transforms the car.

Yep, don't disagree with anything there. I *think* I can tell the difference in terms of the performance of the car but without a scientific/back to back test its impossible to know if this is real or just placebo, and I can remember that EVO did a test a few years ago on a Golf GTI (TFSI engine) that gave increased power with shell optimax (vpower) but I can't find anything around the mpg improvements.

In theory there should be a benefit, after all, higher octane = more bang hence less fuel required for the same performance but I can't find any research that backs this up.

I've pinged an email to Skoda customers services to see what they say - I'll post the answer here.

The Octane rating is not an indication of calorific value but a measure of resistance to pre-ignition (or knock). A vehicle with knock sensors can adjust the spark timing to minimise the combustion time and therefore develop the bigger bang you mentioned.

The theory is that with the bigger bang you need less rpm to achieve the same speed. In reality you are talking 10's of rpms saved which on an engine doing 2000 rpm at cruise is miniscule. However it is less and as such can be legally quoted by the petrol companies.

There seems to be quite a bit of good information here:-

http://www.fuelsaving.info/fuels.htm

But, I’m still not clear in my own mind if a litre of 98RON has a approx 5% more energy than 95RON, so could offset the cost by going 5% further. I’m sure it must be possible to calculate, but it’s beyond me!

Anyway, subjectively my TSI seems to go better on 98RON (when ‘pressing on’).

But, I’m still not clear in my own mind if a litre of 98RON has a approx 5% more energy than 95RON, so could offset the cost by going 5% further.

The Octane rating is not an indication of calorific value but a measure of resistance to pre-ignition (or knock). A vehicle with knock sensors can adjust the spark timing to minimise the combustion time and therefore develop the bigger bang you mentioned..

That answers my question then!

Edited 11 September, 201213 yr by JBD1974

I don't know about in the UK, but here in Aus, the VW/Skoda/Audi petrol's are known for using the higher grade fuel.

Here we have: RON91-E10 (10% ethanol); RON91 (rare places); RON95; and RON98.

Every VWaG requires RON95 minimum.

Does anyone know why they can't run it on the RON91-E10? (About 20-40c/ltr cheaper, in most places)

Engine components need to be of the right materials to cope with the ethanol. I think plastic seals in particular can be damaged by biofuels if they're not of the right type.

Much like the change from leaded to unleaded not that long ago. Unleaded damaged valves unless you used additives.

There seems to be quite a bit of good information here:-

http://www.fuelsaving.info/fuels.htm

But, I’m still not clear in my own mind if a litre of 98RON has a approx 5% more energy than 95RON, so could offset the cost by going 5% further. I’m sure it must be possible to calculate, but it’s beyond me!

Anyway, subjectively my TSI seems to go better on 98RON (when ‘pressing on’).

Some interesting stuff there.

Links to this page on the BP web site: "BP Ultimate fuels help your engine to run at its most efficient, so as little precious energy as possible is wasted – helping you get more miles from your tank".

Shame they don't quote a % increase figure, but either way it's something I can share with my boss..

On previous cars I've played about with fuels over same journeys etc (commuting 120 mile a day at the time!)

Basically it worked out like for like as I got about 5 to 10 % more mpg so couple of pence per litre was offset. Fuel cards work out well too as you get cheaper than the price at the pump.

Standard Octavia 2 TSI runs fine ie 95 Octane but some fuels with additives can help clean the combustion chamber ie Shell petrols, Tesco Momentum.

1.8T engine, such as in Mark 1 Octavia VRS, Leon Cupra with that engine seemed to prefer 98 Octane when we had those.

Fabia 2 VRS petrol cap states it should run on 98 Octane and will have less power/economy on 95 Octane.

Tesco Momentum worth putting through occasional as it is only a bit more than standard petrol. Shell V-power seems good but a bit pricey, other higher octane fuels from other fuel stations are not even 98 octane sometimes ie only 97.

Ambrosia runs on Sainsbury's 97 Ron, as does Bert

Few weeks back had a 1000 mile journey down south stopping at a few places and the whole 1000 miles and even until now i used Shell 95 fuelsave and still easily get 430 miles to a tank of fuel.

I'm beginning to think it doesnt matter on the ron aslong as its decent fuel i.e shell bp etc.

Confirmation from Skoda UK customer services - my vRS is designed to run on super unleaded and as such that is their recommendation - as per the sticker on the fuel flap (above). It won't cause any damage to run on regular but it will not be generating the stated power and won't be as efficient.

Clears that up then!

Confirmation from Skoda UK customer services - my vRS is designed to run on super unleaded and as such that is their recommendation - as per the sticker on the fuel flap (above). It won't cause any damage to run on regular but it will not be generating the stated power and won't be as efficient.

Clears that up then!

Not really as the owners manual states different and that written by Skoda!.

It says 95 MINIMUM, but also says SUPER.

I take that to mean that the car is designed to be run on (recommended) Super, but can run on any fuel that has min 95 ron. Am i right?

Dirty boy! Looks like the flap of an old transit!

The wonderful thing is that if you do not want to follow the Manufacturers recommendation you just try what you want.

You know how you drive and what you want from your vehicle.

Maybe try Tesco Momentum 99 Ron, or Shell V Power, Sainsbury's Super Unleaded 97ron.

A few tanks of the same stuff on your regular run in that season,

because winter might well be different from summer.

If only that you might be going slower in winter but be warming up the car for longer and the alternator is working harder.

So test the fuel with a higher octane, then compare after doing your journeys with the lower octane or cheaper fuels

with a 95 ron minimum.

http://www.pertolprices.com

Then you will be in a position to tell us how your tests & comparisons went.

George

Not really as the owners manual states different and that written by Skoda!.

I looked at the manual and it said basically look at the sticker in the flap? Unless you're reading something different?