Premiumfuel

[donc]

After sometime using supermarket fuel I recently changed to premium in an attempt to improve emissions and a smokey exhaust. Must report it has worked wonders . The car a 1.8t runs smoother and the exhaust is visibly cleaner. Has anyone else found this?

[macafee2]

Only when towing a caravan have a noticed an improvement, normally I'd just fill up with standard. Now I have a diesel I just used standard towing or solo

macafee2

[coolguy]

Never used supermarket fuel - my mechanic says they don't put as many additives in, which it why it is all of £2.00 per fill up cheaper. Not worth the risk.

[Gigagator]

Supermarket fuel is garbage, I tend to avoid at all costs unless its the works van.

The main benefit of premium fuels seems to be the added detergents they put in to keep the engine and fuel systems cleaner, though you are likely to see a benefit of this only through prolonged use, not just a single fill up of premium once or twice a year.

That being the case, I would think premium fuel would be of more benefit to diesel owners as it tends to be a dirtier fuel in the engine.

If you are after economy benefits, it's a bit of a grey area.

I'm not sure about diesel as I've never owned a diseasel, but with petrol, a higher RON fuel typical of premium unleaded allows you to more comfortably change up a gear at slightly lower revs due to an increase in low down torque.

I am adamant I can feel this in my 75 - running on supermarket fuel it just feels lazy so you have to give it an extra 200-300rpm before shifting up, particularly noticeable when on a slight incline.

This is where you can in theory save a few pennies on your cost of fuel as changing up earlier means you keep the revs down which in turn means you are using less fuel. Whether it outweighs the additional cost of putting the premium fuel in your tank is another argument altogether.

I don't believe there is any economy benefit to using a premium fuel if you are sitting at 70 on the motorway all the time - the benefit is to be had lower down in the rev range.

Personally, I only use premium because I like the idea that it keeps the fuel system and engine cleaner than a cheaper fuel, which I appreciate when running an older set of vehicles such as ours.

I have read many stories about people that struggled to get their older cars through the MOT due to failing the emissions tests, but a good use of premium fuel beforehand seems to get it through.

I previous had an Alfa Romeo MiTo with the TwinAir engine (900cc, 2-cylinder, turbocharged) and it ran like absolute shizz on supermarket fuel and sounded like a bag of spanners - it was notably better on premium.

[cantabro75]

I use allways premiun diesel ( optima is called here)
my car is Stage 1 to 175 cv.
Economy ? well i made 80 klm dayle 95% motorway and 5% 5 city
Driving 95-100klm /h i made 5.8 liters on 100klm
driving 120-130 i made 6.5 liters on same
i think not so bad for a 16 years old car whit 243.000 klm

[Arctic]

Mike Noc on here was reported to have some of the best injectors on the forum, he only ever uses supermarket diesel i think, his car is now 400,000 miles and counting if i am right.

[Parker]

https://blog.greenflag.com/2019/cheap-supermarket-fuel/

Worth a read keep the thread going

[Ched]

My last zt190 threw up on different occasions the eml light, plugging the code reader in threw up two fault codes, both banks were running lean, the car was running on asda fuel.
I then decided to try shell unleaded, the first tankful gave me 50 more miles out of it over the asda stuff, replicated on every tank fill afterwards, my journey to work was a 264 mile round trip, and never again did the eml light come on.

I now run a derv zt and I currently do a 202 mile round trip to work, I use either tesco or shell fuel, and I do get a better mpg from shell fuel.

I did run the car on asda fuel when I first had it, since I stopped using it the car seems more responsive and certainly doesn't smoke on acceleration and I get a better miles to tank range.

[Mike Trident]

Yesterday I decided to fill our Kia Venga 1.4 petrol with shell v max fuel to see if I could notice any difference.

Actually, after a few miles (probably needed to get the new fuel into the engine) the answer was a definite yes!

The engine is much more responsive on the shell v max. In terms of more max power, I dont know. It is the low down pick up where the difference is felt. Its not surprising really when you think about it. Years ago when your engines ignition timing was pretty much fixed, if you ran a lower octane fuel you would be able to hear the engine pinking under load. Pinking is really bad for an engine, if left unchecked would eventually cause the engine to self destruct. So you either filled up with an higher octane fuel or retarded the ignition timing. Retarded ignition will loose you power.

Modern engines have knock (or pinking) sensors fitted. As soon as one of these sensors picks up on any pinking, the ECU will automatically back off the ignition timing to the point where pinking stops, and magically moves it back when the engine has stopped trying to self destruct.
All this happens within a split second, and the driver will be totally unaware of it.

So, what does this mean exactly? Well if you fill up on a fuel with a lower octane, or a fuel that has a tendency to cause pinking, your engines ECU will be retarding the ignition quite a lot, which will make your car a little more sluggish. Fill up with an higher octane fuel, or one with less tendency to cause pinking and your ECU doesn't need to back off the ignition timing so your car should feel more responsive. You will feel it most on low revs pick up. The pick up in general should feel more responsive, which is exactly how my Kia feels running on the Shell V Max. This in turn should in theory give me more miles per gallon, simply because I don't need to be as heavy on the throttle to keep up with traffic.

However, is it worth the extra cost? Does it balance itself out? I don't know. Our Kia feels so much nicer to drive on the Shell V max, but can i justify the extra cost? Fortunately for me, the Kia is used for my work, so my fuel is a tax deductible expense.

Will supermarket fuel damage anyone's engine? A definite no! By law, all fuels must meet standards. So using supermarket fuel will not do any damage.

Someone compared premium brand cornflakes to supermarkets own label brand. Both are cornflakes, but i can tell the difference!

[johnnyb44]

I notice that using premium fuel over supermarket diesel the car engine sounds more refined. It somehow has a more mutted tone to it overall. The performance is slightly better (hardly noticeable in real road conditions)