Snagger Posted May 18, 2013 Share Posted May 18, 2013 Unfortunately James Tesco can't just shop around. They are the biggest fuel retailer in the UK, probably selling in excess of 100 million litres per week!!!It all a very closely scheduled business so they and the majors need to plans to refine, store and land the product into the UK to an expected level of demand. With each tanker carrying 35000 litres or so they cannot shop around... Really guys, its all the same stuff. The regular diesel is, but the premium diesel is modified. I've never seen it at supermarkets, though, and if I have a Tesco discount voucher, then I'll use it. I use Tesco fairly often anyway, as we have a clubcard and get a lot of points on it, which has paid for a few Channel crossings, a fair few Legoland and Alton Towers tickets, and iPod and god knows what else, which can be included in the "economy" calculations. Quote Link to comment Share on other sites More sharing options...
Aragorn Posted May 18, 2013 Share Posted May 18, 2013 It's simpler than that - the lower grade fuel burns less well, so you have to throw more in to get the same energy. Acceleration is reduced, so you spend more time in lower gears, and more unburnt fuel goes out the exhaust when cruising, which is why lower grade fuels create more smoke. With petrol engines i'm not sure thats entirely true. Standard 95 octane fuel ignites and burns easier than the "super" 98/99 octane stuff. Thats the whole point of using the high octane stuff in a turbocharged engine. When the cylinder charge is cranked up (ie lots of boost), the 95 has a tendancy to explode in an uncontrolled fashion, or at least combust very quickly. The high octane stuff burns slower and in more controlled fashion, and thus more energy can be extracted from it. As a result, putting high octane petrol in an engine thats NOT mapped for it, usually sees a reduction in economy, because the management system doesnt advance the ignition timing enough to offset the fact the fuel is harder to ignite. High performance engines are mapped to take advantage of the additional octane rating, and use knock sensors to figure out how much advance they can get away with on the fuel that happens to be in the tank. Interestingly, this article suggests diesel is actually almost the complete opposite, which i guess agrees with your comment: http://en.wikipedia.org/wiki/Shell_V-Power#V-Power_Diesel The fancy diesel has a higher cetane rating, meaning it ignites easier, but given how diesels work, thats a good thing. Quote Link to comment Share on other sites More sharing options...
Quagmire Posted May 18, 2013 Share Posted May 18, 2013 Is anyone registered on fuelly.com? Some of the stats on there make for interesting reading and having the phone app makes it easy to record fill ups... I have both our cars registered although haven't filled up the 90 and tracked it yet, only the VW... Quote Link to comment Share on other sites More sharing options...
Snagger Posted May 18, 2013 Share Posted May 18, 2013 With petrol engines i'm not sure thats entirely true...The fancy diesel has a higher cetane rating, meaning it ignites easier, but given how diesels work, thats a good thing. Fair enough, but given the title of the thread it's diesel that I thought we were talking about! Quote Link to comment Share on other sites More sharing options...
Aragorn Posted May 18, 2013 Share Posted May 18, 2013 Is anyone registered on fuelly.com? Some of the stats on there make for interesting reading and having the phone app makes it easy to record fill ups... I have both our cars registered although haven't filled up the 90 and tracked it yet, only the VW... I use fuelly but i find my mileage fluctuates constantly due to the different types of driving i do. Makes it sort of difficult to see anything like a trend from different fuels. http://www.fuelly.com/driver/aragorn/a4-quattro-2/fuelchart Quote Link to comment Share on other sites More sharing options...
V8 Freak Posted May 18, 2013 Share Posted May 18, 2013 The regular diesel is, but the premium diesel is modified. I've never seen it at supermarkets, though Sorry, for clarity.... Standard diesel will be the same in Supermarkets & Majors... Premium diesel derivatives will be different. Quote Link to comment Share on other sites More sharing options...
Lorrick Posted May 18, 2013 Share Posted May 18, 2013 It might be a daft thing, but the 10k, might actually be the reason all the smoke and Cr%p comes out of the exhaust, if it doesn't combust properly or is designed to make smoke when heated, giving the illusion it is all the rubbish coming from the engine, I can not see that a squirt from an aerosol would instantly clean a carboned up engine ? only an Idea Quote Link to comment Share on other sites More sharing options...
Aragorn Posted May 18, 2013 Share Posted May 18, 2013 I've never tried it, but folk say that it spews carp everywhere the first few times, but it then gets less and less on subsequent applications, suggesting some sort of "cleaning out" effect. However, simply spraying water (in suitably small amounts ofcourse!) into the intake would do exactly the same thing, essentially steam cleaning the cylinders. If you've ever looked at a cylinder head of an engine where the gaskets failed, you often find the cylinder with the leak is spotless, the steam having cleaned all the deposits off the cylinder walls, pistons, valves, head etc. I expect the 10k spray stuff, and other products of a similar nature work on a similar principle. Quote Link to comment Share on other sites More sharing options...
Gremlin Posted May 19, 2013 Share Posted May 19, 2013 This tread has come up right in time, on some real concerns on fuel quality here. We are getting such crappy diesel here that we need to seek some sort of cheap additive. Sadly we have no choice when it comes to fuels, just one company, which has no obligations from where to source the fuel we buy. So they buy any cheap carp. In my case (land rover series tdi 200) On normal diesel performance is pretty poor and smokes black under hard accelleration, i then went for a 40% bio diesel (also one company with very doubtful resources) and performance improved with little or no smoke......... but we often get a load of brown sludge in the filters, even with normal diesel. Many cars have been having trouble with injection systems with the current diesel, from failed injectors to pumps, and these are mainly on modern cars, the older ones tend to spring leaks from every where (very thin diesel) I have been doing some reading and i see the 2 stroke oil theory as an additive coming up often. Now does anybody know of a company willing to do fuel testing?? from overseas?? as i am real curious of what sort of carp we are getting! Test kits maybe?? prices??? Ideas?? G Quote Link to comment Share on other sites More sharing options...
Lorrick Posted May 19, 2013 Share Posted May 19, 2013 I think ocean liners have the right idea, buy solid Bitumen and heat it up till runny and then put it through your engine, 100's of thousands of trouble free travel at 100 yards a gallon ?. I have tried the new advanced diesel from Shell as i picked up the wrong pump by mistake, and it did not make a ha'penny's worth of difference, except for my wallet (Ouch). Quote Link to comment Share on other sites More sharing options...
V8 Freak Posted June 25, 2013 Share Posted June 25, 2013 As I said I would..... Recent MPG results.... Not doing anything out of the ordinary.. Some trips I get bored and push it around a bit and others I'm quite content to sit on cruise control at 60.... I'll continue now without additive and see how it goes... I "think" the engine was smoother a low rpm and revved a little better when pushed.. But now I have to figure if it was my imagination... Was it worth £1.50 per tank extra... Only the next few tanks will tell... Quote Link to comment Share on other sites More sharing options...
ajh Posted June 26, 2013 Share Posted June 26, 2013 Most diesel 'additive' is non-detergent oil thinned with naptha. For lubrication you get better results with a B5 bio blend than all the various additives. http://www.dieselplace.com/forum/76-gm-trucks/64-maintenance-fluids/177728-lubricity-additive-study-results.html Quote Link to comment Share on other sites More sharing options...
Aragorn Posted June 26, 2013 Share Posted June 26, 2013 V8Freak - Would be worth trying the same but using Shell VPower diesel or similar to see how that compares to normal-derv-plus-additive? Quote Link to comment Share on other sites More sharing options...
Dan110 Posted June 26, 2013 Share Posted June 26, 2013 For what it's worth, I got chatting to a fuel injector specialist recently who owns a pretty big company which does Warranty work for most of the major manufacturers and asked him about additives; he said that most manufacturers - bosch etc either don't recommend using additives or specifically recommend against it, citing the effect of glazing at the top of the system being broken down and falling lower down, causing damage to components. I'm sure there's someone here much better informed than me who could confirm or deny this? I'm not much more than a layman...... Quote Link to comment Share on other sites More sharing options...
V8 Freak Posted June 26, 2013 Share Posted June 26, 2013 Not many places selling the enhanced fuels around me.... And.. My recollection of the premiums per litre would make it more than the £1.50 per tank the additive cost... I'll do a few tanks without additive to make sure it's cleared through the system and maybe try a few V-power tanks..... If no immediate difference I'll be back to boggo Tesco..... Quote Link to comment Share on other sites More sharing options...
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