Super unleaded
Discussion
Well, your engine can make use of it, as it has knock sensors, but anything abobe 98 octane has no extra effect, as your engine would only be rated for 91-98 octane.
I felt a small difference at first, just a wee bit more responsive.
It's been proven to give you extra power (only about 1-2BHP
)
I felt a small difference at first, just a wee bit more responsive.
It's been proven to give you extra power (only about 1-2BHP
)bimmer_87 said:
anything abobe 98 octane has no extra effect, as your engine would only be rated for 91-98 octane.
Really ? Over 98 has *no* effect ?Anecdotal evidence only, but I normally run my E39 530 on
100 or 101 Oktane whenever I am in Germany.
The pull from third gear 100 mph to top gear 140 mph is *so* much
smoother *and* I get more mph too.
Almost no real need for it elsewhere, I find.
I merely put in supermarket cooking 95 Oktane almost everywhere else.
dcb said:
bimmer_87 said:
anything abobe 98 octane has no extra effect, as your engine would only be rated for 91-98 octane.
Really ? Over 98 has *no* effect ?Anecdotal evidence only, but I normally run my E39 530 on
100 or 101 Oktane whenever I am in Germany.
The pull from third gear 100 mph to top gear 140 mph is *so* much
smoother *and* I get more mph too.
Almost no real need for it elsewhere, I find.
I merely put in supermarket cooking 95 Oktane almost everywhere else.
Its not the petrol mate, its that fact you have an M54 engine underneath
But yeh, it says on the back of the fuel filler cap 91-98 and in the manual.
I've always used super unleaded in My BMW's until last weekend.
Trying to economise, I decided to use ordinary unleaded for the first time. Boy what a difference!.
Halfway down the M1 My fuel guage packed up because of a fault with the fuel sender in the tank. That never happened with super unleaded! (Okay, some will say it was a coincidence but I'm convinced the car knew I'd used cheaper fuel and made Me pay for it!).
Everybody here seems to think that the only benefit to using super unleaded is a performance one. Whilst there may be some performance advantage (of which most owners will not even notice), the biggest benefit is with the additional additives in the fuel. Over a period of time, these additives will clean the fuel system of your car, thus improving the the combustion process and make it more efficient.
You pays your money, you make your choices, just don't expect the results to be instant.
Trying to economise, I decided to use ordinary unleaded for the first time. Boy what a difference!.
Halfway down the M1 My fuel guage packed up because of a fault with the fuel sender in the tank. That never happened with super unleaded! (Okay, some will say it was a coincidence but I'm convinced the car knew I'd used cheaper fuel and made Me pay for it!).
Everybody here seems to think that the only benefit to using super unleaded is a performance one. Whilst there may be some performance advantage (of which most owners will not even notice), the biggest benefit is with the additional additives in the fuel. Over a period of time, these additives will clean the fuel system of your car, thus improving the the combustion process and make it more efficient.
You pays your money, you make your choices, just don't expect the results to be instant.
Evo did a huge fuel test and with a number of performance cars, super made a difference in economy and dyno results. Not sure how much effect it would have on an older leggy car though.
I do notice a difference between v power and tesco 99 octane in my (supercharged) 2.8 Z3. On my bike, I can never tell any difference.
I do notice a difference between v power and tesco 99 octane in my (supercharged) 2.8 Z3. On my bike, I can never tell any difference.
StuB said:
Evo did a huge fuel test and with a number of performance cars, super made a difference in economy and dyno results. Not sure how much effect it would have on an older leggy car though.
I do notice a difference between v power and tesco 99 octane in my (supercharged) 2.8 Z3. On my bike, I can never tell any difference.
I remember fifth Gear did something similar a few years back, looking for any power increases with super unleaded,(it'll be back on Dave tv soon no doubt).They tried supermarket unleaded Vs BP ultimate and Shell Optimax (the original version of what became Vpower). I do notice a difference between v power and tesco 99 octane in my (supercharged) 2.8 Z3. On my bike, I can never tell any difference.
I seem to recall that with an average family runabout the difference was negligable and that it was not worth the extra expense but with an Imprezza turbo, the difference was quite noticeable, especially on the Shell fuel.
I'm not sure if they mentioned the extra cleaning ability of the super unleaded as they were concentrating on performance gains.
4rephill said:
the biggest benefit is with the additional additives in the fuel. Over a period of time, these additives will clean the fuel system of your car, thus improving the the combustion process and make it more efficient.
Urban legend, surely ?All UK saleable petrols are required by law to contain fuel
system cleaning additives.
I suspect that a car that is set up by the manufacturer to run
anything over 91 oktane in a large range of conditions from
Arctic Norway to desert Saudi Arabia won't have too much trouble
with any of 95, 98 or 101 in the UK's somewhat temperate climate.
Of course, higher octane petrol will burn at a slightly higher
temperature, but that's something different.
I use shell V Power where ever possible in my V8 Alpina, at times when no "super" is available I have used Reg unleaded the difference I see is drop in economy, not by much though , I'd say 2 mpg on normal driving, performance wise not a lot of difference so I advise to stay with normal forecourt fuel BUT avoid the Supermarkets as mostly their supplies are of lower Quality
dcb said:
4rephill said:
the biggest benefit is with the additional additives in the fuel. Over a period of time, these additives will clean the fuel system of your car, thus improving the the combustion process and make it more efficient.
Urban legend, surely ? This is going to start WW 3 but the octane rating is unimportant as a petrochemical engineer can "brew" a fuel that has no relation to life in the real world, if in doubt add toluene! F1 turbo cars ran 80% toluene 20% chemicals so it tested as petrol but was in reality rocket fuel capable of withstanding effective compression ratios of 24:1
dcb said:
4rephill said:
the biggest benefit is with the additional additives in the fuel. Over a period of time, these additives will clean the fuel system of your car, thus improving the the combustion process and make it more efficient.
Urban legend, surely ?All UK saleable petrols are required by law to contain fuel
system cleaning additives.
I suspect that a car that is set up by the manufacturer to run
anything over 91 oktane in a large range of conditions from
Arctic Norway to desert Saudi Arabia won't have too much trouble
with any of 95, 98 or 101 in the UK's somewhat temperate climate.
Of course, higher octane petrol will burn at a slightly higher
temperature, but that's something different.
Fuels such as BP Ultimate and Shell VPower go well beyond this minimum level, offering much superior cleaning ability and this in part is the reason for their extra expense.
This has been covered before in another thread. Whilst the base fuel will be identical, the blends of additives will not be.
If you do a chemical breakdown of the same octane rated fuels from Tesco's, Sainsbury's, Esso, Shell, BP etc, you will find that they are not identical. If they were identical, why would they give different power output results in independant fuel tests, using the exact same car for each fuel sample?.
I believe on the fifth gear test, the imprezza turbo showed an increase of something like 18 BHP running on the Shell fuel in comparison to the supermarket fuel. So where did this increase come from if the fuels are identical?.
If you do a chemical breakdown of the same octane rated fuels from Tesco's, Sainsbury's, Esso, Shell, BP etc, you will find that they are not identical. If they were identical, why would they give different power output results in independant fuel tests, using the exact same car for each fuel sample?.
I believe on the fifth gear test, the imprezza turbo showed an increase of something like 18 BHP running on the Shell fuel in comparison to the supermarket fuel. So where did this increase come from if the fuels are identical?.
I am convinced that my old 330ci ran smoother and had better consumption with 98 petrol and it preferred V power.
Having said that, Tesco 99 was ok as well but....
If I occasionally ran my TVR Chimaera on Tesco 99 (through necessity rather than desire) it ran like a bag of nails every time.
KTM recommend Super on my 950SM as did Triumph on my Sprint a few years ago.
BMW's handbook recommended Super fro prolonged motorway use IIRC.
As said above, there must some proper reason for all this other than lining BP/Esso/Shell's pockets.
Having said that, Tesco 99 was ok as well but....
If I occasionally ran my TVR Chimaera on Tesco 99 (through necessity rather than desire) it ran like a bag of nails every time.
KTM recommend Super on my 950SM as did Triumph on my Sprint a few years ago.
BMW's handbook recommended Super fro prolonged motorway use IIRC.
As said above, there must some proper reason for all this other than lining BP/Esso/Shell's pockets.
DavidLScott said:
I am convinced that my old 330ci ran smoother and had better consumption with 98 petrol and it preferred V power.
I thought that about my 330Ci too. Then I slowly realised after some experimentation that it preferred BP ultimate (97), but liked BP102 even better (but the price of that was just obscene, far more than you could justify through the extra 1-2mpg). Main thing about the 102 was the more smooth effortless delivery of performance. It seemed to make the engine sound more bassy too. I couldn't make a habit of it though. It would be cheaper to have a coke habit.
Edited by a_bread on Wednesday 2nd December 17:33
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