Lots of viewpoints, little agreement.

My own opinion (I run a 2013 BMW 325 diesel) is that if it keeps the fuel system cleaner and possibly prevents an EGR failure, then it's worth the extra cost.

It costs me roughly £3 per week for Shell VPower diesel over the standard diesel, £150-£160 per year. The cost of an EGR change on my car is about £400.

For some cars (the VW 1.6 diesel, for example) changing an EGR valve costs £600+.

You roll the dice as you see fit. Some people reckon it's a waste of money.

I doubt you'd notice a difference with just one tank. You'd probably have to fill it up several times to really notice anything. My Accord i-CDTi doesn't seem to gain anything from performance fuel but it sure doesn't like supermarket fuel.

You pay your money and make your choice I guess. If you're a low-mileage driver then paying a premium may not be such a big deal.

When Fifth Gear was still on telly, they did a back-to-back test on the dyno of supermarket ordinary unleaded, compared with Shell and BP premium fuels. All they did was drain the tank of one fuel, fill with the next, and tested the power & torque outputs.

See for yourself: www.youtube.com/watch?v=gQghB4asSnI

Basically, a non-turbo car will show little if any benefit. However, a turbocharged higher-performance car that is capable of adjusting its timing, boost and fuelling according to the grade of fuel will get significant gains, over 10bhp in some cases.

I have just emptied my tank on the car and decided for the first time in my life, I filled her up with the high octane unleaded premium fuel. Only costing me £6 more for a full tank! I was just wondering if all the rumours are true? Better economy? Better performance? Does anyone know the facts and whether it's best for me to continue using the premium expensive fuel? Thanks in advance!

Like Craig, I too saw the 5th Gear report/test (its available on You Tube BTW) on the difference between standard 95Ron unleaded petrol (from both supermarkets and branded filling stations) and super 97/98Ron unleaded petrol from the branded stations.

My analysis of their results:

• The used a (at the time of the show) a brand new Golf GTi as the sole car for the test, which in my eyes skewed it a lot. Yes, the super fuels did achieve a noticeable, but not huge increase, and a lot less in percentage terms than the extra money they cost. What seemed to be more noticeable was that the car 'felt' better when driving with the super UL fuels, with greater responsiveness throughout the rev range.
• What they didn't do was test the other two types of car that would be worthwhile, namely 1) an 'ordinary' (not performance) car, and in particular one that didn't have a knock sensor and ECU that can adjust the engine to take advantage of the higher octane fuel (which the Golf could), and 2) an older car (perhaps 10 years old or more) or two (one performance, one standard) that was in less good condition than brand new ones, with possible issues such as clogged fuel injectors, carbon deposits on the pistons etc.
• They did do another similar test video (why) that essentially confirmed the results of the first.
• 5th Gear's other test of which things boosts performance of older cars (in that case, a 90s VW Corrado) showed that specialist fuel additives (in that case, Redex injector cleaner additive) made the best difference (still only about 4-5bhp out of about 165-170 to start with) in terms of value for money (about £4-5 for a 4-tank treatment bottle) compared to remapping, new tyres, ete etc.

I would say generally that if you have:

1. A new, but standard car (not high performance [Golf GTi or better]), then 95Ron from any petrol station (other than if they have a bad rep - presumably storage problems/contamination) is fine, as long as you keep the car well maintained, drive on a reasonable range of roads, variable speeds and revs in each gear and not just on short (particularly urban) journeys. This gives the car the chance to burn off any nasties that may gunk up the injectors and engine, and decent maintenance generally more than aids this. Super UL may, with its extra cleaning additives, give an extra measure of cleaning, but won't make that much of a difference to performance or mpg when new, as even if does have a knock sensor, the car isn't powerful enough to make that much of a difference, as the clip showed, but certainly won't do any harm (except to your wallet if you do a lot of mileage per year);
2. A new performance car would benefit more, not markedly, though some (and the higher the performance the more it does) do more than others, especially those that state they recommend superfuels in the manufacturer's handbook. Again, if you have to choose between using them and decent maintenance (with 95Ron), then I'd go for the latter.
3. An older non-performance car may benefit once in a while, especially coming up to MOT time, from the extra cleaning additives of the superfuels or external products like the Redex I mentioned. I myself am going to test this out over the next few weeks when I go on one decent length journey and a much longer 1000 mile holiday trip (including whilst there) to the South West by using both superunleaeded and Redex on my 11yo Mazda3 1.6 petrol - its well-maintained, but I want to see if either/both together make any difference at all. I'll probably keep some of the Redex leftover for the end of the year to use prior to the MOT, though its always easily passed the emissions test up 'till now and never had (touch wood) a failure yet.
4. An older performance car almost certainly would benefit from superfuels, especially if it did have a knock sensor and it had been not kept in prime order - many such cars are far less hardy than the bog standard ones and react really well, as the Corrado did, to a bit of TLC. Again, a well-maintained car won't benefit as much as it would've lost less performance as a result of the better care. Not worth using it on a right banger though, whether performance or not.

A lot is really both trial and error to see which fuels react well (or not) with your car (including actual driving, not just looking 'rolling road' test figures), as the clips show, sometimes the super fuels or additives help to smooth out flat spots in the power/torque curve by the cleaning effect, which can make the driving experience better, even if the mpg or max. acceleration doesn't improve a great deal. Similarly for long term reliability - some cars, and more likely the higher performance ones, will benefit more in this respect than bog standard cars. Most people seem to think using 3 to 4 complete fill ups (say 1000 - 1500 miles) of a different fuel (whether make and/or type) will normally be enough to tell if there any difference.

From what others here have said, it seems that the super diesel fuels CAN make far more of a difference than the super unleade petrol ones, probably because of the extra contaminents (soot etc) that is produced as a by-product of the combustion process, and especially if the car if often drive on short journeys where the car doesn't get the chance to warm up and burn those nasties off. The super fuels seems to help do that as, presumably through their own cleaning additives, help clean off any contaiminents before a regen is done, which when it is works better than with odrinary diesel.

I think it would be rare on a well kept car to get both better mpg and performance to the same percentage degree as the difference in fuel price between standard and super fuels, but sometimes thes evary quite a lot - I've seen Shell sell their V-Power SuperUL more than 10p a litre more than their standard, which itself is mostly 2-5p more than at the supermarkets (even before any store discount vouchers are applied), but I've seen the likes of my local Sainsbury's offer 97Ron petrol at a premium of only 5-6p more than the 95Ron standard price (which at the time was within 0.2p of the cheapest elsewhere [Asda]).

It should be noted that the supermarkets and, often even many brands get their fuel from eactly the same sources (and tankers), but they individually add their own 'special' additives at the filling station (a bit like pubs do by adding the branded cola syrup to bog standard carbonated water at the bar hose), thus a Shell, BP and Morrisons filling station might have the same basic 95Ron or 97Ron fuel, but use different/more additives before it reaches the pump.

Quite a timely question!

When I was at Goodwood this year, there was a Shell Fuels stand and they gave me 2 x £5 off vouchers for Shell V Power.

I am proper anal about mpgs as my commute (A roads and B roads) is the same every day with close to the same amount of traffic every day. I check the mpg every time I fillup on my 20 year old petrol car.

So the last two tankfuls have been V Power unleaded........ a slight dip in mpg for both tankfuls. Car felt the same with no increase in perkiness or power.

I have in the past used V Power diesel in my wife's 59 plate diesel. Again a slight dip in mpgs compared to normal.

I always use brand name garages for fuel as there's some really competitively priced ones around these here parts.

I know every squeak, clatter and bang in my car as I've been driving it for 15 years. It's still a perky old beast but it didn't feel perkier using V power compared to brand name unleaded.

So for the extra £6 per fill up, personally it's not for me.

I do have two motorbikes, however, and always use V Power or similar in these as there's less water-attracting-ethanol in these and I don't want rotten petrol tanks.

Edited by V4 Heaven on 11/08/2017 at 09:31