WDB
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Post by WDB on Jan 24, 2024 10:23:55 GMT
Last mentioned here, as far as I can tell, way back in 2016. Well, I’m wearing fleece today (albeit Patagonia rather than Milletts) so here goes.
In December I was on my way to Hampshire with the Thule bike carriers to go on the Aygo. I’d set off a little later than ideal and then realised I’d need fuel. Stopping at the only vacant pump at the Shell near Reading Bridge, I had the cap off and was reaching for the nozzle when I noticed it offered only V-Power, for about a 20p premium. Being short of time, I just went for it.
Now, five weeks on and the long Gloucestershire weekend behind me, I needed more. Plain BP this time, and a fill-to-fill calculation. No discernible difference in consumption or engine behaviour; I’m just £12 down on the tankful. This has been the same with every premium tankful I’ve ever put in any of my diesel cars.
I think fleecy orthodoxy holds that I’d need several successive tankfuls to feel the benefit. So maybe £60 extra just to get to the starting line. Then a return of … how much? 10 percent? Seems unlikely — and still won’t cover the extra cost. And yet the fossil companies keep offering this stuff, so who’s buying it?
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Post by Alanović on Jan 24, 2024 11:25:30 GMT
Mugs.
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Post by Humph on Jan 24, 2024 12:40:39 GMT
My diesel cars have been run almost exclusively on supermarket standard issue diesel. At a rough guess that will equate to well over a million miles of motoring in all conceivable conditions across a variety of vehicles, most of which have been run to large mileages. Not one of them has suffered any mechanical problems as a result and I seem to consistently get more than acceptable fuel economy too.
Snake oil comes to mind.
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bpg
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Post by bpg on Jan 24, 2024 13:52:31 GMT
The real test would be to take the EGR valve off your car and see if it's sooted up or not.
I took the valve off my previous S60 D5 Euro 3 at around 70,000 miles. It was pretty full, roughly a 3" diameter pipe with only the centre about the diameter of a penny unclogged. I started using Miller's diesel additive a couple or three times per year, took it off again at around 90,000 miles there's was no build up.
I've never bothered with premium fuels preferring to do my own dosing if I'm feeling that way inclined.
My S60 D3 Euro 5 which is a more complex EGR setup has not, as far as I am aware, been off the car. I still use a dose or three of Miller's per year.
Now I've got a DI petrol they do soot up, I put a fuel additive through that once per year.
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WDB
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Post by WDB on Jan 24, 2024 14:13:36 GMT
Where does the diesel additive go? In through the fuel tank, presumably, but then? What’s left of it, post-combustion, to clean the EGR valve? Or is it that the heat of the exhaust gas does the cleaning, if it’s not bringing new soot to deposit?
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bpg
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Post by bpg on Jan 24, 2024 14:25:55 GMT
As a diesel engine is direct injection it cleans up the pre injection residue of the injectors leading to less crap coming out the other side. DI petrol engines build up carbon on the inlet side leading to a less efficient burn, keep the input side clean then you only have to deal with the result of the combustion rather than the build up being pushed through.
The injector sits in the combustion chamber with the heat baking crud onto it leading to a reduced mist for combustion. I have not stripped down the injectors as I've never had to replace them or the glow plugs. Neither has Humph, maybe his servicing place puts an additive in one or twice per year when they service it, maybe they don't. I don't know.
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bpg
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Post by bpg on Jan 24, 2024 15:30:47 GMT
An interesting test, hypothetical as it'll never happen, would be too get your car, Humph's and mine together and take the EGR valves off and compare.
None of us have knowingly paid for repair or replacement if the valves, that would prove snake oil or otherwise.
Next conversation, cheapo tyres, middle of the road or premium brand ? They are all round, mostly black and have to meet minimum standards.
Wiper blades: Valeo, Bosch or from the budget supermarket middle isle next to wet suits, flippers and golf clubs? They have to be C€ or whatever the UK standard will be to sell and use.
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Post by Humph on Jan 24, 2024 16:39:44 GMT
Decent tyres are like good shoes. You don’t actually have to buy them, but it is the right thing to do.
😉
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bpg
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Post by bpg on Jan 24, 2024 17:07:29 GMT
Back to WDB's question of who is buying the premium fuel. I have maps on my car ECU. Standard, calibrated to run on E10 95RON petrol and a race map which can give me an extra 85PS but needs 98 or 99RON E5. I don't know if diesel maps require a similar upgrade in the fuel cetane rating.
Not everyone will be buying it because of the claimed cleaning properties would be my answer. You can buy petrol here with 102RON, vital to those looking for the last 1/1000th of a second off their lap of the Nordschleife I suppose.
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Rob
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Post by Rob on Jan 24, 2024 18:22:02 GMT
I've only used premium fuel a few times... can't remember the exact difference but one of the diesels certainly did more MPG but it did not save any money - still more costly. Most cars up until recently were company cars so I would just use supermarket fuel.
Most cars we might run can probably do so fine on standard E10 95RON petrol for example. Some more exotics need 98RON. If you were to run an RS6 on bog standard petrol in the USA you'd blow the engine (91RON?).
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Post by EspadaIII on Jan 24, 2024 19:45:32 GMT
I occasionally used premium fuel and the only difference I noticed was a slightly smoother running of the engine. But then the use was usually accompanied by a long motorway run which probably got rid of a load of gunge anyway.
Wipers - always try to buy a decent brand - they certainly last longer.
Tyres - for Espadrille I buy premium brands. For me I buy either top middle of the road or premium. I suspect I can only get premium for the I5. Have about 5.5mm left on each corner after 19,000 miles, so will look to replace next Autumn. The Punto has new cheapos on as it does less than 2,500 miles a year. The boys' cars get middle of the road.
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bpg
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Post by bpg on Jan 25, 2024 9:32:01 GMT
It's not just the preserve of remapping to take advantage of the higher grade fuel.
A few manufacturers of performance cars, thinking Subaru, and Nissan Skyline in addition to the German überwagons used knock sensors and varied the engine timing when higher grade fuel was detected giving a bit more performance.
Conclusion: it's not just bought by mugs or sold by snake oil salesman, some cars, bought by car enthusiasts, do benefit from the higher specification. There must be enough of them to make it worth the fuel companies while to make and sell it. Putting it in a car not setup to take advantage does seem a bit pointless though.
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WDB
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Post by WDB on Jan 25, 2024 9:40:37 GMT
I occasionally used premium fuel and the only difference I noticed was a slightly smoother running of the engine. Really? Or just confirmation bias? The Sprinter V6 diesel sounds a bit lumpy at town speeds (by BMW inline standards anyway) and is barely audible above that. |
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Post by EspadaIII on Jan 25, 2024 11:58:23 GMT
Given that the majority of my time in the lowered Sprinter was around town, I did notice something but in reality it wasn't enough to justify regular purchases, hence the use mainly before long trips which may have benefitted the engine anyway.
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