Petrol - supermarket vs Vpower

[Jamesf1]

Ive had my GS250 for a few months now and covered 5000 miles. I've only ever filled up with Shell Vpower. I usually have the "after refill" MPG in the 28-29 range by the time I've used a full tank. This is with motorway driving accounting for 10% or so of the mileage.

A few days ago I filed up with a tank of tesco standard unleaded and straight away struggled to get the after refill mpg into the 26's mpg and just managed 27.1 mpg after 15 miles of relaxed motorway driving (65-70 mph). I'll see how it goes but so far the extra expense of Vpower pays for itself with better mpg. Ive never seen such  difference between vpower and standard unleaded before including on my IS250.

[AmbroseJohn]

V power is for high performance engines, which the GS250 doesn't have. Expensive fuels are slower burning, like the old leaded petrol, to cope with the higher compression ratios of performance cars. Ignition timing has to be advanced so the slower burn takes place in the correct position in the cycle. If you search the net you will find many studies on the subject and all come to the same conclusion. There is no advantage using performance fuels in cars that don't require it.

Lexus are designed to run on regular fuels.

 

[Jamesf1]

yes I agree, except I'm not using vpower for performance, I use mostly for the cleaning detergent  s the 250 engine has had carbon build up issues reported in the past. However, having switched to normal unleaded, due to circumstance at the time I needed to fill up, I've suffered the drop in MPG that I wasn't expecting.

Modern cars are designed to run on either, but my understanding is as you've stated ;The more powerful the engine the bigger difference high octane fuel makes. With the GS I haven't noticed any perceivable difference in performance.

[steveledzep]

Maybe the mpg difference is due to you filling up with supermarket fuel and not a normal brand like Shell or Texaco ?

 

There are many factors that affect mpg and your limited sample of low mpg is too small to be conclusive.  A month on one fuel followed by a month on another fuel would be more indicative of true mpg (assuming similar temperatures).

[Jamesf1]

 

54 minutes ago, AmbroseJohn said:

V power is for high performance engines, which the GS250 doesn't have. Expensive fuels are slower burning, like the old leaded petrol, to cope with the higher compression ratios of performance cars. Ignition timing has to be advanced so the slower burn takes place in the correct position in the cycle. If you search the net you will find many studies on the subject and all come to the same conclusion. There is no advantage using performance fuels in cars that don't require it.

Lexus are designed to run on regular fuels.

 

True it is early days but seeing my MPG drop by 2.5-3 straight away and still not showing much improvement over a few days - when I'm driving same route in the same way - still a bit suprising.

[AmbroseJohn]

As someone has already mentioned, temperature also makes a difference. Summer mileage will always be better than winter.

[royoftherovers]

29 minutes ago, AmbroseJohn said:

As someone has already mentioned, temperature also makes a difference. Summer mileage will always be better than winter.

So we have;

Quality of fuel

External temperature,

and if we add

Anticipatory skills, thus reducing effects of braking and accelerating

Type of Terrain covered

Speed at which travellled,

Vehicle body coefficient

Type of propulsion eg, electic, hybrid, solar etc

Nose or Tail wind

anybody add anything else ?

 

Regards

John

[NemesisUK]

Barometric pressure

Humidity

Tyre pressure

Tyre Tread

Vehicle loading

[AmbroseJohn]

There's an infinite number of variants but most can be ignored because because the same car is being used for the test. However because of relevant variables, the test period must be over a much greater time, than one tank of different fuel.

[AmbroseJohn]

BTW I never bother checking, I just put the fuel in and enjoy it. Speaking as someone who has been used to gas guzzlers most of my life, getting over 15mpg is a dream. :)

[royoftherovers]

1 minute ago, AmbroseJohn said:

BTW I never bother checking, I just put the fuel in and enjoy it. Speaking as someone who has been used to gas guzzlers most of my life, getting over 15mpg is a dream. :)

I always do brim to brim checks John.Something I have done since owning my first car in 1966--a Morris Minor which always gave 33.3 mpg. I do it because I have trained my self to do it and the knowledge gained can sometimes be symptomatic of a potential problem.

I have a neighbour however, who religiously keeps a check of his consumption to 4 decimal places and compares his figures annually.My idea of O.C.D !!

 

rEGARDS

jOHN

 

[NemesisUK]

The only reason I monitor mpg is to check for any downward trend, hopefully to be forewarned of any potential problems.

[AmbroseJohn]

I used to run an A class modified at the drags. It had a 2 gallon fuel tank and often ran out of Petrol/Methanol mix, on the way back to the paddock after the quarter mile race. :)  

We ran it on 5 star and the tank size was adequate. When 5 star was discontinued in the late 70s, the class rules were changed to allow 4 star plus 20% methanol, which was required to cope with our 13/1 compression ratio. The mixture had to be increased so consumption went up, making the tank size border line.

This is how I gained much of my, now useless, knowledge. :)

[Jamesf1]

2 minutes ago, AmbroseJohn said:

I used to run an A class modified at the drags. It had a 2 gallon fuel tank and often ran out of Petrol/Methanol mix, on the way back to the paddock after the quarter mile race. :)  

We ran it on 5 star and the tank size was adequate. When 5 star was discontinued in the late 70s, the class rules were changed to allow 4 star plus 20% methanol, which was required to cope with our 13/1 compression ratio. The mixture had to be increased so consumption went up, making the tank size border line.

This is how I gained much of my, now useless, knowledge. :)

At first I thought you meant an A class Merc lol

[royoftherovers]

2 minutes ago, Jamesf1 said:

At first I thought you meant an A class Merc lol

So did I James !!

 

Regards

John

[Jamesf1]

1 hour ago, royoftherovers said:

So we have;

Quality of fuel

External temperature,

and if we add

Anticipatory skills, thus reducing effects of braking and accelerating

Type of Terrain covered

Speed at which travellled,

Vehicle body coefficient

Type of propulsion eg, electic, hybrid, solar etc

Nose or Tail wind

anybody add anything else ?

 

Regards

John

pretty sure most of this didnt change significantly in Chorley in my GS between Monday and Wednesday

[rayaans]

Ive always found Tesco Standard Unleaded and Diesel to be poor quality

This is from my own observations but my wife's C220 CDI was mainly run on BP diesel (Purely out of convenience as our area is predominantly a BP area). Anyway, it was fine. 

We put one tank of tesco diesel in as the local BP was being refurbished and noticed a drop in MPG, response and the RPMs would shiver around 3k. I thought heck, this must just be a bad batch of fuel so run the car on BP again for the next 2 fills at which point it was fine and went to Tesco again to test it out. Exact same issue - the Merc just didnt like it.

At this point I was filling up with Tesco standard unleaded in my RX300 and it ran fine (or what I presumed to be fine). Thats until I had this issue with the Merc that I started using BP standard unleaded in the RX to see if there was a difference. Turned out that the RPMs dropped by 0.5-1k and economy was also improved. I swear the RX300 made a nicer purr as well running on BP

[AmbroseJohn]

1 hour ago, Jamesf1 said:

At first I thought you meant an A class Merc lol

No, it was a Mkiii Cortina body shell, with 327ci (5300cc) small block Chevrolet V8. Highly modified, producing over 600 bhp and covering the quarter mile in 10.73 seconds @ 138 mph.

Happy days, then I got married to that awful woman and the cars had to go. (Race car, '71 Corvette & '69 396 Chevelle SS)

[AmbroseJohn]

Contrary to popular belief most fuels are refined in the same refineries. Oil companies deliver to refineries pay to have it refined then collect it for distribution. So it's pretty much the same stuff. Shell and Tesco stuff all comes out of the same storage tank. Some companies add things afterwards but I think it's just to legalise sale gimmicks.

[AmbroseJohn]

UK refineries from Wikipedia. No BP, Shell, Esso, Texaco or Tesco, just petrol and stuff.

 

United Kingdom[edit]

England

• Coryton Refinery (Petroplus), 175,000 bbl/d (27,800 m³/d) shutdown;converted to terminal in 2012
• Fawley Refinery (ExxonMobil), 330,000 bbl/d (52,000 m³/d)
• Humber Refinery (Phillips 66), 221,000 bbl/d (35,100 m³/d)
• Lindsey Oil Refinery (Total), 223,000 bbl/d (35,500 m³/d)
• Teesside Refinery (Petroplus), 117,000 bbl/d (18,600 m³/d) Closed 2009
• Stanlow Refinery (Essar Oil), 272,000 bbl/d (43,200 m³/d)

Scotland

• Grangemouth Refinery (Petroineos, a joint venture of Ineos and PetroChina), 205,000 bbl/d (32,600 m³/d)

Wales

• Milford Haven Refinery (Murco),135,000 bbl/d (21,500 m³/d) Closed in November 2014
• Pembroke Refinery (Valero), 215,000 bbl/d (34,200 m³/d), Nelson Complexity Index 10.1^[25]

[Britprius]

My brother inlaw used to be a fuel delivery driver for BP. His normal bulk filling depot was at Kingsbury off the A5 near Tamworth.

At this depot you can see just about every fuel tanker of whatever brand filling up from the same lines. This includes all the well known companies, and super markets.

The only additive that was added to his fuel loads was a red dye to turn ordinary diesel to red diesel for heating and farm use. After filling with diesel the next call was always customs, and excise. They checked the quantity of fuel and it's colour to ascertain what duty would be charged on that load.

Many people do not understand that the higher the grade of petrol you buy the lower it's calorific value (the amount of energy it contains). 

John.  

[soramad]

In my GS430 I use Sainsburys 98 ron un-leaded, I used it in my Soarer which actually according to Toyota required 100 ron being a 4ltr with a 10-1 compression ratio by the same token being the same engine but up rated I thought it would be prudent to use the same grade petrol.

[dutchie01]

i have something else.....  Perception

mate of mine worked in tossa de mar, spain in the old days, behind the bar in an "english pub"

they had 3 different beers on tap, san miguel, heineken and carlsberg. Thing is all pipes went into one can, the cheapest they could buy on the black market..

he frequently told me about ( inabriated ) customers that did not like the san miguel then tried heineken and were convinced it was way better.

could it be that one thinks tesco is not as good as it is tesco and not shell?

 

[AmbroseJohn]

8 minutes ago, dutchie01 said:

i have something else.....  Perception

mate of mine worked in tossa de mar, spain in the old days, behind the bar in an "english pub"

they had 3 different beers on tap, san miguel, heineken and carlsberg. Thing is all pipes went into one can, the cheapest they could buy on the black market..

he frequently told me about ( inabriated ) customers that did not like the san miguel then tried heineken and were convinced it was way better.

could it be that one thinks tesco is not as good as it is tesco and not shell?

 

We tend to believe what people tell us without any evidence if they have any qualifications giving them a right to an valid opinion.

Some people even believe politicians, owners of multi national companies, bankers and the BBC. I do believe some people even think Bob Geldoff and Eddie Izzard know what they're talking about. :)

[royoftherovers]

14 hours ago, dutchie01 said:

i have something else.....  Perception

mate of mine worked in tossa de mar, spain in the old days, behind the bar in an "english pub"

they had 3 different beers on tap, san miguel, heineken and carlsberg. Thing is all pipes went into one can, the cheapest they could buy on the black market..

he frequently told me about ( inabriated ) customers that did not like the san miguel then tried heineken and were convinced it was way better.

could it be that one thinks tesco is not as good as it is tesco and not shell?

 

INEBRIATED, are you "sozzled", John ?    :):):)

 

Regards

John