Petrol thread lifted from general forum...........
Discussion
Interesting.......
www.pistonheads.com/gassing/topic.asp?t=151895&f=13&h=0
www.pistonheads.com/gassing/topic.asp?t=151895&f=13&h=0
Very interesting stuff.
Wonder why he seems to praise Optimax earlier on and then derides it at the end. Confusing. I always thought it was rather good.
Quite vociferous views opposing the original author!
I rarely use supermarket fuels, but anyone agree with what he was saying, or are all fuels derived from the same central sources?
JJ
Wonder why he seems to praise Optimax earlier on and then derides it at the end. Confusing. I always thought it was rather good.
Quite vociferous views opposing the original author!
I rarely use supermarket fuels, but anyone agree with what he was saying, or are all fuels derived from the same central sources?
JJ
Interesting but the comparison between your major oil companies and supermarkets is unfounded, as far as I am aware there is no difference between the fuel from either source as it originates from the same refinery, (One reason for high oil price is limited refinery capacity to meet demand).
As for using Eastern crude that too is unfounded as UK crude or Brent crude is mixed with Middle East Crude and others for the various outputs from the refinery. Bearing in mind that petrol is only a small percent of a refineries output (Plastic, Pharmaceuticals etc are the major outputs) it would be commercial suicide to segment the Tesco's and ESSO's fuel.
Price is down to basic business sense, the supermarkets buy in bulk, your BP, Shell etc petrol stations are usually independent/franchise so basic economy of scale, on top of this the supermarkets sell the fuel at either break even or a slight loss as it draws in the shoppers.
One point I do agree with and that is Optimax, in contrast to many threads on PH and IMHO and experience my Cerb and Griff ran so much better on basic unleaded so possibly it could be a hit or a miss.
As for using Eastern crude that too is unfounded as UK crude or Brent crude is mixed with Middle East Crude and others for the various outputs from the refinery. Bearing in mind that petrol is only a small percent of a refineries output (Plastic, Pharmaceuticals etc are the major outputs) it would be commercial suicide to segment the Tesco's and ESSO's fuel.
Price is down to basic business sense, the supermarkets buy in bulk, your BP, Shell etc petrol stations are usually independent/franchise so basic economy of scale, on top of this the supermarkets sell the fuel at either break even or a slight loss as it draws in the shoppers.
One point I do agree with and that is Optimax, in contrast to many threads on PH and IMHO and experience my Cerb and Griff ran so much better on basic unleaded so possibly it could be a hit or a miss.
I think there is some truth to both arguments. I believe the majority of retailers get their fuel from the same refineries and so the basic fuel is the same wherever you buy it (excluding differences in octane). Where the difference between the supermarket and the branded fuels comes in is the amount of detergent additives that are put in at the refinery. The branded (Esso, BP etc) allegedly put in more than the supermarkets. But this is difficult to investigate as the legislation for fuel quality in the UK does not define the amount of additives required. Consequently, I believe that 95 octane from Tesco will make your engine go as well as that from Shell. The difference may be long term, when the Tesco fuel may make your engine (mainly the inlet valves, combustion chamber, and injectors) dirtier.
As far as the difference between 95 and 97/98 octane is concerened, the fuel itself will only make the engine run better if it is tuned for it. Basically the octane rating is a measure of how far advanced the ignition can be without causing pinking. (Fuel is evaluated for octane using a single cylinder engine with a variable compression ratio. The octane rating is measured by assessing the compression ratio at which the tester hears pinking.)If you tune the engine for 95 octane and put 98 in, you will not see any difference. Tune it for 98 and put 98 in, and you may get some improvement, but it depends on the engine configuration, and I don't know enough about the TVR engine to comment. On the other hand, tune it for 98 and run it on 95 and you will probably get pinking.
Bearing in mind, the relative scarcity of the higher octane fuels, the small mileage range of the Wedge and the limited improvement to be gained from 98, I run mine on Tesco 95. If it begins to run roughly (and it hasn't yet after 15,000 miles in my ownership), I'll run it for a while with a supplemetary additive to clean it out.
As far as the difference between 95 and 97/98 octane is concerened, the fuel itself will only make the engine run better if it is tuned for it. Basically the octane rating is a measure of how far advanced the ignition can be without causing pinking. (Fuel is evaluated for octane using a single cylinder engine with a variable compression ratio. The octane rating is measured by assessing the compression ratio at which the tester hears pinking.)If you tune the engine for 95 octane and put 98 in, you will not see any difference. Tune it for 98 and put 98 in, and you may get some improvement, but it depends on the engine configuration, and I don't know enough about the TVR engine to comment. On the other hand, tune it for 98 and run it on 95 and you will probably get pinking.
Bearing in mind, the relative scarcity of the higher octane fuels, the small mileage range of the Wedge and the limited improvement to be gained from 98, I run mine on Tesco 95. If it begins to run roughly (and it hasn't yet after 15,000 miles in my ownership), I'll run it for a while with a supplemetary additive to clean it out.
jmorgan said:
So why dont ASDA (BP pumps) sell Ultimate????
Guessing here but I suppose some companies will have thier own particular version. Could these still be done at the refinery or are they dealt with off site?
I would suggest those marketeer people won't allow it to maintain branding and brand recognition.
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