Viewing 40 posts - 1 through 40 (of 41 total)
  • do 'supreme' or super fuels actually make a difference?
  • Pook
    Full Member

    I’ve filled up with supreme diesel today, and apart from the eye watering cost per litre, do they actually make much difference? And if so, how? I can’t say I noticed any performance benefits

    mikewsmith
    Free Member

    Used to end up at the expensive pump on a Friday afternoon before heading back up the M6 some weeks. It was expenses so not as bothered but I reckoned I was getting the same p/mile so slightly higher MPG but a higher £/l price.

    There were a couple of times where it made hedges and stone walls see through so I could “make progress” on blind bends though 😉

    tall_martin
    Full Member

    I tried them

    They increased the mpg of my car slightly, not enough to pay for the higher price. No performance benefit that I noticed.

    remapped mk1 octavia vrs

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    cardo
    Full Member

    They contain better / more / some detergents that normal and certainly supermarket fuels do not have. All these do is help to clean the fuel system of gluey deposits from injectors and the internals of the injection system prolonging the life of the components… In theory a cleaner system will run more efficiently and is less likely to glue up especially if you run a variable vane turbo (VW) or a EGR exhaust gas recirc system… Most people don’t thrash their Turbo diesels and pootle around which causes most of the these sooting up and gluey problems… I run a tank of super through if we have a decent journey to do and everything is going to get a good work out…

    speed12
    Free Member

    Depends on the engine. The main feature of these fuels is that they have a higher RON (98 or 99 typically). What this means is that the fuel is less prone to uncontrolled combustion (knock) which is very bad for the engine. Modern engines will have a way to retard the ignition if it detects knock – this then pulls the spark away from the most efficient angle and so the combustion isn’t as efficient, but is stable. With higher RON fuel, the engine can run the spark angle nearer to the optimum angle and so combustion is more efficient.

    In ‘normal’ cars this isn’t going to make a massive amount if difference as they won’t be particularly prone to knocking anyway (although as engines get smaller and turbocharged the possibility of knock increases). If you have a reasonably old car, then it will make zero difference as it might not even have knock control. However a ‘performance’ engine could notice quite big gains, and indeed might HAVE to run on higher RON fuel in order to operate safely, especially when driven at high load.

    The other benefit of these fuels is that they have other additives which are good at cleaning out high pressure fuel lines and injectors – these are present in standard fuel but are sometimes a bit better in the higher RON fuel.

    So yes it does make a difference. Is it noticeable? Probably not massively for your family hatchback. Certainly is for your weekend Ferrari…

    speed12
    Free Member

    Oh, and to add – all that was for petrol engines. The Diesel ‘super’ fuels pretty much just have different additives, although will usually have a higher Cetane number as well – essentially the same as the RON, but you are a LOT less susceptible to auto-ignition issues in a diesels the thing basically runs on auto-ignition! (Although it is possible and pretty bad when it happens)

    cardo
    Full Member

    Didn’t think I had seen many diesel Ferraris…. 😉

    speed12
    Free Member

    Haha, not yet at least….

    speed12
    Free Member

    (Yeah missed the bit where Pook mentioned it was diesel he filled up with………)

    Jamie
    Free Member

    I can definitely taste the difference.

    treaclesponge
    Free Member

    Ive found that I get much fewer DPF regens using them than ‘regular’ or supermarket fuel. Performance wise nothing and MPG maybe 1 or 2, however anything that stops the DPF being a problem is worth its weight in gold!!

    oldnick
    Full Member

    Accidently put some in my 52 plate Focus Tddi and after a few miles the engine warning light that had been flickering on and off for the previous year or so went out and stayed out. The effect lasted for the next few tank-fulls of normal diseasel.

    When combined with fully synthetic oil in the MX bike it meant the piston crown and head could be wiped clean, no carbon deposits at all.

    trevron73
    Free Member

    My old swift sport ran on 97 to 99 RON fuel, if i used normal 95 RON fuel i lost mpg and about 10 bhp i reckon , i used the ggod stuff 75% of the time . I got more MPG and a touch more fun , i used to feel more torque for over taking and bends ect , it made me smile more so was worth It . 😛

    craigxxl
    Free Member

    When I first got my car I was treating it to he premium diesel. It made it run a bit smoother with a better MPG but not enough to cover the extra you paid for the fuel per litre.
    I use a heavy duty fuel system cleaner annually now such as BG244 or AR6400 and supermarket fuels. Car runs just as smooth and better MPG than using premium fuels. At £20 a year for the treatment much cheaper than using the more expensive fuel too.
    You can also use a fuel additives such as Miller Sport 4 which do the same as the premium fuels which increase the detergents and cetane rating.

    oliverd1981
    Free Member

    Is the amount of tax your pay on a litre of super the same as your pay on a litre of regular? In that case it’s actually not really such bad VFM – as the fuel price has come up the premium to go for super seems to be coming down – at least in % terms.

    molgrips
    Free Member

    Speed12 is right when it comes to petrol but like a true petrolhead he doesn’t seem to be familiar with the wonders of diesel 🙂

    The super expensive diesel does have a higher cetane number as well as better cleaners etc. This means smoother running, better starting, better MPG and more power, supposedly. Of those, I really noticed better starting and smoother running, and a slight improvement in mpg but as others said, it’s not that much.

    The additive that increases the cetane number btw is called 2-EHN which you can buy on ebay for cheap – sold for people who want to use veg oil in their old diesels. You can add petrol to thin the veg oil out but this lowers the cetane number, so you add this to bring it back up.

    Ive found that I get much fewer DPF regens using them than ‘regular’ or supermarket fuel.

    Oh yeah.. good point – less smoke is another benefit.

    grenosteve
    Free Member

    It’s all I put in the bike. The engine runs much smoother and nicer on super. I’m not sure you’d notice the effect in a car though.

    unklehomered
    Free Member

    My 10yrs old mondeo does less MPG than normal fuel station diesel on super fuels, but more than on supermarket diesel. It hasn’t had exhaustive testing, as soon as it became clear they weren’t actually super I went back to the standard

    tinybits
    Free Member

    I filled up with BP super diesel stuff this morning. MK7 golf with the 2l tdi. In my mind, there’s no doubt you get an increase in power, coupled with the smoother running means you’re more likely to let the revs build a bit which adds to the effect.
    Not too sure about better economy, mine tends to vary a lot more based on traffic conditions than fuel type (60miles a day on B-roads)
    I don’t however do it in my A6 family tank as I actually pay for the fuel in that (other is a company car) so not enough of a difference for me to pay for I guess!

    thisisnotaspoon
    Free Member

    I’ve tried it (petrol) in the MG and in the focus.

    My tuppence, seems to make a difference, whether that’s placebo or the engine cleaning out is another matter. I suspect the MG actualy benefits more as the cylinders are generaly filthy compared to the almost surgicaly clean internals of the focus.

    Also, Esso premium is about 6p/litre more than standard, others are more like 15p, so the focus usaly gets ESSO premium once a month, the MG gets the fandabidozey Optimax all the time because it doesn’t do many miles so it’s not a big expense.

    TurnerGuy
    Free Member

    Shell V+ made a difference in the petrol Alfas I have had – more torque at low revs and maybe a little smoother, but my normal miles per tank would go from about 330 to 380 – unless I offset that by driving a little harder to make use of the increased torque…

    The other premium petrols didn’t seem to make much difference.

    Tom83
    Full Member

    Used to run my high spec classic mini engine on premium unleaded, ran a lot better. This was a few years back when it was under a quid, however! Don’t think I could afford to now.

    Northwind
    Full Member

    I get the common “better fuel economy but not as much as the cost increase” in my remapped 2.2 mondeo. No other obvious benefits or downsides though.

    I used to be convinced I got better throttle response in the motorbike but considering it was carbed, fixed ignition map etc I suspect I just imagined that.

    DenDennis
    Free Member

    question about the cleaning benefits of the higher grade fuels:

    if I put some of that ‘REDEX’ stuff in with a normal fuel, would this have equivalent cleaning benefits?
    and any other benefits?

    klumpy
    Free Member

    Depends on the engine. The main feature of these fuels is that they have a higher RON (98 or 99 typically).

    [quote]Oh, and to add – all that was for petrol engines.[/quote]
    True dat. High octance diesel never really caught on.

    cbmotorsport
    Free Member

    My last 4 cars have been reasonably powerful turbocharged petrol ones. They all seemed to run better on Super+/Supreme. I’ve never really considered the MPG, but from a smoothness and perceived power point of view, they’ve run better.

    breadcrumb
    Full Member

    I had an import Honda Prelude, it definitely ran better on SUL, and got more miles too, was worth the extra.

    It was mapped for Japanese fuel though, 100ron iirc.

    molgrips
    Free Member

    With petrol, if your car is designed to use it*, then higher octane fuel will work better as sure as physics is physics. No maybes about it, it’s not snake oil.

    With diesel, all cars will benefit from higher cetane fuel, but the extent seems to vary.

    The cleaning additives – well, they may work, but a modern engine shouldn’t get that dirty to begin with so who knows.

    * this means a high enough compression ratio or a turbo and the ECU software to vary the timing appropriately (afaik) which is most sporty-ish cars. The handbook should tell you if higher octane is recommended.

    thisisnotaspoon
    Free Member

    if I put some of that ‘REDEX’ stuff in with a normal fuel, would this have equivalent cleaning benefits?
    and any other benefits?

    Probably, redex is just a concentrated mix of detergents in petrol. That and red* colouring and thickeners to make it look more expensive on the shelf. But redex generaly costs more per tank than premium petrol. And although it cleaned the engine out, I’m (subjectively) of the oppinion that the premium petrol works better.

    *science fact: a refinery processed a crude that produced green coloured kerosene (jet fuel), nothing wrong with it, but no airline would touch it. So they added a clay filter to the stream to bleach it. Don’t undestimate they psycology of the colour of somehting!

    tinybits
    Free Member

    IIRC, the test I’ve seen (think it was 5th gear, on a rolling road with readout), show that petrol additives added at best nothing, at worst degraded performance of an otherwise sound engine.
    The same test done on the premium fuels showed a 5-10% increase in performance, and a bit better economy. About the same as turning off the aircon in most cars (top tip for close overtakes there :wink:) achieves.
    Of course, having seen the tests, I’m convinced they work in my car, however a guy I used to work for who had a 500bhp M6 said he could really feel the difference which I guess you would, my car at the time didn’t have the additional 50bhp he gained to start with!

    molgrips
    Free Member

    tinybits, I think you need to mention that they tested three different types of car in that test.

    brassneck
    Full Member

    DPF regens- how do you know you’re getting them? I thoguht you forced your own with an Italian tuneup every so often, that’s what the manual infers anyway.

    My First Diesel 😀

    HoratioHufnagel
    Free Member

    Fifth gear test here..
    https://www.youtube.com/watch?v=gQghB4asSnI

    Impreza Turbo went from 235bhp to 250bhp. Renault – no difference.

    popstar
    Free Member

    I drove car(passat 2.0 cr tdi) with supermarket diesel, got 52mpg @70mph on motorway on some trip. On start up engine as usual was rattly and once warm sounded allright sure as diesel.

    Then experimented with Shell Nitro diesel and had 52-54mpg @70mph on some trip. On start up, engine sounded softer and once warm it worked softer and smoother.

    And ultimately filled up with supermarket fuel but this time added Millers Ecomax diesel additive. Got 55mpg @ at 70mph on 100mile round trip. On start up engine purrs like Cheshire cat, once warm you easily can mistake it for petrol engine sound.

    Sui
    Free Member

    the add packs are not just detergents, they are also their under other various performance guises.

    With Petrol, one of the bigger differences you can feel is from a Shell VPower as it has a higher olefin content which increases the flame burn speed, the octanes too are higher for ignition advance (antiknock), and the general burn characteristics will have distillation profile more matched to higher RPM engines.

    Diesle’s is more about Cetane as has been said, though detergents do play a big part in ensuring the nozzles do not coke up affecting spray pattern, which in turn will effect combustibility within the chamber.

    have a read of this as it will explain the dynamics behind it.

    http://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCAQFjAA&url=http%3A%2F%2Fwww.springer.com%2Fcda%2Fcontent%2Fdocument%2Fcda_downloaddocument%2F9783642029516-c1.pdf%3FSGWID%3D0-0-45-1201437-p173959960&ei=0oTrU8vkGcyS7AbwhoGIDA&usg=AFQjCNEZgGlvurVpxmhpvxl8xFnX6-iumQ&sig2=bWDT5D11E1kXPpVahTPLAg&bvm=bv.72938740,d.ZGU

    toby1
    Full Member

    better MPG

    More expensive fuel = less change in pocket = lighter right leg/foot = better fuel economy 😉

    molgrips
    Free Member

    DPF regens- how do you know you’re getting them?

    It does regens when you are driving, usually. You only get the light when you’ve not driven long enough for the cycle to complete and it then asks you to go for a longer drive – that’s the italian tuneup bit although it would probably prefer moderate revs and throttle as per the instructions I suspect.

    People have said that they can tell when it’s doing it as they drive, as the engine sound/response changes.

    TurnerGuy
    Free Member

    More expensive fuel = less change in pocket = lighter right leg/foot = better fuel economy

    or rather more expensive fuel, more torque, heavy right foot, same economy…

    tinybits
    Free Member

    I would have done if I’d remembers enough molgrips, but I couldn’t so didn’t!
    I’m still convinced the car does feel different though, even though at 20k miles, it really should not be in any way coked up meaning the detergents will have made sod all difference.

Viewing 40 posts - 1 through 40 (of 41 total)

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