Shell Optimax/V-Power 99... has anyone else noticed ....

[pilchardthecat]

.... that they've changed it somehow?

Been using it for a while in the Z4M and whenever i put BP or supermarket super-unleaded in i get about 1-2 mpg less than with Shell (23/24 vs 25/26). This has been consistently true since August last year. Top end fizz is noticeably better with V power too.

The current tank of V power is giving me really stty mileage, much like the supermarket stuff does. Has anyone else noticed this?

[johnathanc]

I USE V POWER IN MY EVO, IF I ADD OCTANE BOOST WITH IT IT GOES MUCH BETTER.

[Garlick]

johnathanc said:

I USE V POWER IN MY EVO, IF I ADD OCTANE BOOST WITH IT IT GOES MUCH BETTER.

GOOD TO HEAR

[Prof Prolapse]

1-2 mpg less?

How the hell can you actually notice that much of a difference?

Have you changed you shoes perhaps?

[Evil.soup]

Prof Prolapse said:

1-2 mpg less?

How the hell can you actually notice that much of a difference?

Have you changed you shoes perhaps?

[pilchardthecat]

Prof Prolapse said:

1-2 mpg less?

How the hell can you actually notice that much of a difference?

Have you changed you shoes perhaps?

My commute is such that I use a tankfull every 4 days, and normally i get to the Shell garage near my house with the "miles remaining" thing at about 20-30 miles left.

The last 2 tanks it's been at "--" ie bugger all, so it's quite obvious. 2mpg over a tank is 20-30 miles range so very noticeable if you have a regular pattern like that.

[Fun Bus]

I'm glad it's not just me. I've justed started running my car on V-Power and am not getting the same mpg / range - about 3mpg less. I've only just put the 3rd tank in though so may need to give it more miles.

[Rude-boy]

Garlick said:

johnathanc said:

I USE V POWER IN MY EVO, IF I ADD OCTANE BOOST WITH IT IT GOES MUCH BETTER.

GOOD TO HEAR

PARDON?

I did have a little wonder about this myself as i tend to maily use V Power and noted that the Av. MPG on the Boxster was a digit or two lower than it had been the last time i checked.

Sorry I can't help for the mo though as I have no idea what I'm getting from the CS which i am bout to start moitoring and trying to remember how to change MPL into MPG

[Prof Prolapse]

pilchardthecat said:

Prof Prolapse said:

1-2 mpg less?

How the hell can you actually notice that much of a difference?

Have you changed you shoes perhaps?

My commute is such that I use a tankfull every 4 days, and normally i get to the Shell garage near my house with the "miles remaining" thing at about 20-30 miles left.

The last 2 tanks it's been at "--" ie bugger all, so it's quite obvious. 2mpg over a tank is 20-30 miles range so very noticeable if you have a regular pattern like that.

I'm just trying to make the point that 1-2 mpg is a very small amount to measure. So much so that you couldn't possibly know unless you've got an incredibly elaborate method that you've not eluded to.

You could run a million tanks of fuel, however because the squidgey life form behind the wheel can unconsciously make a good few MPG difference just by driving style you won't be able to work out which it is.

If you want to know you'll have to set up some sort of benchmark that is less subjective to human error.

That's why so much marketing is aimed at, "increasing MPG". It's almost certainly the Placebo effect in all but a very tightly controlled environment.

Anyway, I was just making a point.

[fido]

Other factors may be involved .. Cold weather? Heating on all the time? Psychological effects of increasing fuel prices?

[pilchardthecat]

Prof Prolapse said:

pilchardthecat said:

Prof Prolapse said:

1-2 mpg less?

How the hell can you actually notice that much of a difference?

Have you changed you shoes perhaps?

My commute is such that I use a tankfull every 4 days, and normally i get to the Shell garage near my house with the "miles remaining" thing at about 20-30 miles left.

The last 2 tanks it's been at "--" ie bugger all, so it's quite obvious. 2mpg over a tank is 20-30 miles range so very noticeable if you have a regular pattern like that.

I'm just trying to make the point that 1-2 mpg is a very small amount to measure. So much so that you couldn't possibly know unless you've got an incredibly elaborate method that you've not eluded to.

You could run a million tanks of fuel, however because the squidgey life form behind the wheel can unconsciously make a good few MPG difference just by driving style you won't be able to work out which it is.

If you want to know you'll have to set up some sort of benchmark that is less subjective to human error.

That's why so much marketing is aimed at, "increasing MPG". It's almost certainly the Placebo effect in all but a very tightly controlled environment.

Anyway, I was just making a point.

I get your point, but I've been driving the same commute in the same traffic conditions in the same car using the same fuel for the last 8 months. For the last 30-odd tanks i've gone there-and-back 4 times and then filled up with 20 or 30 miles range left. The last 2 tanks i've been clenching my butt cheeks wondering if i'm going to run out of fuel on the trip home on day 4.

I have quite a few data points (i'm such a boring habitual creature and my life is bursting with routine) so when somehting changes it's pretty obvious to me... call it OCD if you like.

[alfabadass]

I've noticed my current tank full hasn' given my car the usual urge in 1st 2nd and 3rd....in fact I suspect i've been sold normal unleaded not V-power!

[Prof Prolapse]

pilchardthecat said:

I get your point, but I've been driving the same commute in the same traffic conditions in the same car using the same fuel for the last 8 months. For the last 30-odd tanks i've gone there-and-back 4 times and then filled up with 20 or 30 miles range left. The last 2 tanks i've been clenching my butt cheeks wondering if i'm going to run out of fuel on the trip home on day 4.

I have quite a few data points (i'm such a boring habitual creature and my life is bursting with routine) so when somehting changes it's pretty obvious to me... call it OCD if you like.

With my scientist hat on, the problem is not your number of data points, it's the lack of controlling and/or measuring the other variables such as those mentioned above.

I know that sounds a little overkill but it's honestly the only way you could say that the change of fuel made any difference.

Given that fuel standards are pretty high nowadays and the fuel produced is consistent, I'm afraid it's more likely to be you and/or your vehicle (or driving conditions) than the fuel (unless of course there have been some dodgey batches floating around).

That isn't to say there aren't other advantages to running on premium fuel of course. It's just almost impossible to demonstrate better fuel economy out of the lab.

Anyway I'm sure there are vast numbers of people desperate to insist that they gain 2mpg regularly and have done thousands of miles to demonstrate this.

Edited by Prof Prolapse on Thursday 3rd March 14:36

[Crusoe]

Last week was mostly above 4 deg so your air conditioning will be kicking in giving you a small drop in mpg?

[pilchardthecat]

Prof Prolapse said:

pilchardthecat said:

I get your point, but I've been driving the same commute in the same traffic conditions in the same car using the same fuel for the last 8 months. For the last 30-odd tanks i've gone there-and-back 4 times and then filled up with 20 or 30 miles range left. The last 2 tanks i've been clenching my butt cheeks wondering if i'm going to run out of fuel on the trip home on day 4.

I have quite a few data points (i'm such a boring habitual creature and my life is bursting with routine) so when somehting changes it's pretty obvious to me... call it OCD if you like.

With my scientist hat on, the problem is not your number of data points, it's the lack of controlling and/or measuring the other variables such as those mentioned above.

I know that sounds a little overkill but it's honestly the only way you could say that the change of fuel made any difference.

Given that fuel standards are pretty high nowadays and the fuel produced is consistent, I'm afraid it's more likely to be you and/or your vehicle than the fuel (unless of course their have been some dodgey batches floating around).

That isn't to say there aren't other advantages to running on premium fuel of course. It's just almost impossible to demonstrate better fuel economy out of the lab.

Anyway I'm sure there are vast numbers of people desperate to insist that they gain 2mpg regularly and have done thousands of miles to demonstrate this.

The net effect of those variables is defined by the variance, which I feel is quite low as shown by high levels of consistency and low levels of variation between those 30-40 previous data points. Of course it's possible that something else has changed, but i don't think so. I suppose that's why i posted this - if lots of other people have noticed a change in the fuel then perhaps there has been one, if not, then perhaps i'm imagining things.

I think it's entirely possible that due to the recent fuel price issues they have changed the composition of the fuel (the supermarkets tend to use more ethanol, less petroleum = same octane rating but lower calorific value and hence lower mpg.... and higher margins)

[Balmoral Green]

fido said:

Cold weather? Heating on all the time?

But both of those would improve fuel consumption. Or would they? perhaps having to punch through colder denser air offsets any performance advantage in burning colder denser air?

[Prof Prolapse]

pilchardthecat said:

The net effect of those variables is defined by the variance, which I feel is quite low as shown by high levels of consistency and low levels of variation between those 30-40 previous data points. Of course it's possible that something else has changed, but i don't think so. I suppose that's why i posted this - if lots of other people have noticed a change in the fuel then perhaps there has been one, if not, then perhaps i'm imagining things.

I think it's entirely possible that due to the recent fuel price issues they have changed the composition of the fuel (the supermarkets tend to use more ethanol, less petroleum = same octane rating but lower calorific value and hence lower mpg.... and higher margins)

It's been a long time since I've done any stats but even with fag packet maths I really don't think 30-40 data points would be enough to calculate such a variance given the other factors like ambient temperature, tyre wear, vehicle maintenance. Which would all need to closely monitored.

That and unless you're blinded to the fuel you're using such a method is still subject to human... Well... Subjectivity.

I'm up for designing a study if you are.

[Welshbeef]

Tyre pressure
it's been wetter recently so more friction
car getting closer to need a service
condensation in your fuel tank
clogged injectors
coil pack on it's way out

[Greg_D]

Prof Prolapse said:

pilchardthecat said:

I get your point, but I've been driving the same commute in the same traffic conditions in the same car using the same fuel for the last 8 months. For the last 30-odd tanks i've gone there-and-back 4 times and then filled up with 20 or 30 miles range left. The last 2 tanks i've been clenching my butt cheeks wondering if i'm going to run out of fuel on the trip home on day 4.

I have quite a few data points (i'm such a boring habitual creature and my life is bursting with routine) so when somehting changes it's pretty obvious to me... call it OCD if you like.

With my scientist hat on, the problem is not your number of data points, it's the lack of controlling and/or measuring the other variables such as those mentioned above.

I know that sounds a little overkill but it's honestly the only way you could say that the change of fuel made any difference.

Given that fuel standards are pretty high nowadays and the fuel produced is consistent, I'm afraid it's more likely to be you and/or your vehicle (or driving conditions) than the fuel (unless of course there have been some dodgey batches floating around).

That isn't to say there aren't other advantages to running on premium fuel of course. It's just almost impossible to demonstrate better fuel economy out of the lab.

Anyway I'm sure there are vast numbers of people desperate to insist that they gain 2mpg regularly and have done thousands of miles to demonstrate this.

Edited by Prof Prolapse on Thursday 3rd March 14:36

I can't hlp but think that you are being a little difficult PP, the bloke has a clockwork routine that hasn't varied at all in 8 months and overnight is getting in excess of a 10% reduction in fuel economy. That is not background noise imo.

Sometimes, you don't need laboratory conditions to spot the bleeding obvious...

Assuming of course your llambda sensor isn't on the fritz or something, that could easily account for that variation

[jon-]

My track car was missing on the last tank of vpower. Seems to have cleared up this tank though.