SourceJersey Tom wrote:
The whole vid is just a PR thing. Shouldn't get too wrapped up in it, IMO.
Surprising but true, despite the vast amounts of technical effort spent developing a Formula One car, the fuel it runs on is surprisingly close to the composition of ordinary, commercially available petrol.
None - most cars will run less efficiently on 98/99 octane than on lower octanes, as they contain less energy, and most cars don't run high enough compression to get any benefit from an octane rating that high.SiLo wrote:Imagine how much fuel the US could save by using the what we use over here in the UK (98/99 Octane).
it the "T" that makes the differenceGeorge-Jung wrote:I know that the 2.0T engine from Audi and VW runs better on high octane fuel..
Especially on the Aral 102..
They might ask for that in the USA, but in Europe there are cars that are sold that specifically state a requirement for higher octane fuel. Higher octane fuel is quite widely available in western Europe these days.beelsebob wrote:None - most cars will run less efficiently on 98/99 octane than on lower octanes, as they contain less energy, and most cars don't run high enough compression to get any benefit from an octane rating that high.SiLo wrote:Imagine how much fuel the US could save by using the what we use over here in the UK (98/99 Octane).
In fact, even most road going turbos specifically ask for fuel in the 90-94ish range, 98-99 is complete overkill.
Please include US or EU in any "octane" number quotedbeelsebob wrote:in fact, even most road going turbos specifically ask for fuel in the 90-94ish range, 98-99 is complete overkill.
most BMW and Audi engines for example specify 95 to 102 as the operating-range in EU numbers, which I think is 90 to 95 in US numbers? So you might be taking about the same range, just different method of measurement.Well let's look at some recent qualifying results here, eh?George-Jung wrote:I was under the impression that "basically the same" was different to just "same"..
But probably I am incorrect..
For example:
Those two types of colors are basically the same, one is just slightly darker..
vs.
Those two types of fuel are basically the same, one is just slightly faster..
Ah indeed I am quoting US numbers, I had not realized that they were different, and indeed I'm quoting from my car's manual which has a US 1.8T engine, so indeed we're talking about 95-102 in UK numbers.NTS wrote:Please include US or EU in any "octane" number quotedbeelsebob wrote:in fact, even most road going turbos specifically ask for fuel in the 90-94ish range, 98-99 is complete overkill.
I wish I understood fuel more. So as a real world example, my car, which is not a turbo, but a 1.6L recent model, has a 40L tank. We track milage. A fill from one fuel supplier nets around 480km a tank. A fill from another fuel supplier gets about 520km. We use the same octane (91) at both and drive the same (relatively) amount each week (a week between fills). That's a big difference. So is it performance or economy making the difference here? And is the different fuel from each supplier really that different?beelsebob wrote:Note though, the general point still applies, you will not get better fuel efficiency from a higher octane rating, unless your engine is operating at reasonably high compression ratios (read, has a turbo charger). Again, higher octane fuel has less energy density than lower octane fuel, it can just be burned more efficiently, because it resists auto-ignition (and hence knocking) when compressed highly (again, because it's less volatile).
The difference is likely to be simply in the amount of sitting in traffic jams/having to stop at junctions that you did. That and/or your mood on particular days, and hence your driving style.Cam wrote:I wish I understood fuel more. So as a real world example, my car, which is not a turbo, but a 1.6L recent model, has a 40L tank. We track milage. A fill from one fuel supplier nets around 480km a tank. A fill from another fuel supplier gets about 520km. We use the same octane (91) at both and drive the same (relatively) amount each week (a week between fills). That's a big difference. So is it performance or economy making the difference here? And is the different fuel from each supplier really that different?beelsebob wrote:Note though, the general point still applies, you will not get better fuel efficiency from a higher octane rating, unless your engine is operating at reasonably high compression ratios (read, has a turbo charger). Again, higher octane fuel has less energy density than lower octane fuel, it can just be burned more efficiently, because it resists auto-ignition (and hence knocking) when compressed highly (again, because it's less volatile).
Well, it's entirely possible that the two garages do indeed give you slightly different proportions of fuel (as opposed to the other stabilisers/cleaning agents etc added to the fuel). But the majority of the difference is almost certainly in your driving.Cam wrote:I would have always thought fuel quality made a difference - never thought about all the small differences adding up, but I suppose they can. I guess the saying is true "Fuel efficiency cannot be bought in a bottle, it is something that must have come with your vehicle in the first place."
I drive a BMW with a M52 2.8 engine, with a compression ratio of 10.2:1... Now I have to be honest that I don't know if that is high or not.. But when I am in Germany an use the ARAL 102 fuel, it runs better.. is more economic and (at least it feels like this) it has more power..beelsebob wrote:
Note though, the general point still applies, you will not get better fuel efficiency from a higher octane rating, unless your engine is operating at reasonably high compression ratios (read, has a turbo charger). Again, higher octane fuel has less energy density than lower octane fuel, it can just be burned more efficiently, because it resists auto-ignition (and hence knocking) when compressed highly (again, because it's less volatile).
