Petrol star rating

[russ p]

Some people still do, I know folk who won't use supermarket petrol because they believe it's inferior to branded makes.

Thats becouse it is. I used to work into the refinery at Parkeston and I asked if supermarket fuel is different to branded and they told me supermarket fuel does not get the additives that branded does.

Running old cars i always use branded as i need the anti Knock additives to protect my engines

[Welchester]

Of course those were the days when people used to believe that one brand of petrol was better than another, remember "put a tiger in,your tank"?

 

For reasons that I never understood, my father's first railway car, a Ford Cortina (actually it was his second, because at 6' 1" he couldn't fit into the Mini Minor he was originally allocated), had a sticker in the rear windscreen which read "Ich habe ein (picture of a tiger) im Tank".

[Oldddudders]

ISTR when Jaguar launched the E-Type, its ability to run on 2-star was much vaunted. As a very fast and pricey car of its era, this counted for what? If you could afford to buy it the running costs were probably irrelevant!

 

Having today taken delivery of my first petrol car in nearly 20 years, 95 octane is my near future. 

[Titan]

Thats becouse it is. I used to work into the refinery at Parkeston and I asked if supermarket fuel is different to branded and they told me supermarket fuel does not get the additives that branded does.

Running old cars i always use branded as i need the anti Knock additives to protect my engines

 

Indeed. There was someone on a Land Rover forum who was intent on getting the best mpg possible. He could not understand why people did not check the mpg they were getting, especially as it highlighted the difference in mpg different fuels gave. I decided to see for myself, and compared several tank fulls of supermarket diesel with several tanks of Shell diesel - can't remember the exact name but it was the one they were promoting as giving better fuel economy. I measured as accurately as I could, brim full to brim full covering the same journey, which was quite long - using about 3/4 of a tank. The Shell diesel gave me 10% improvement in fuel economy overall, and was less than 10% more expensive so ended up in fact being cheaper to use than the apparently "cheaper" supermarket fuel. This was pretty much in line with what the guy on the forum was saying too. I never use supermarket fuel now unless I am desperate as I have proven to myself it is false economy.

[Horsetan]

ISTR when Jaguar launched the E-Type, its ability to run on 2-star was much vaunted. As a very fast and pricey car of its era, this counted for what? If you could afford to buy it the running costs were probably irrelevant!....

Thing is, the E-Type was noticeably cheaper than other sportscars in its category so, if you did buy one, you were in a sense on a budget.

 

Rotary engines can usually run on fuel with a very low octane rating

 

.....I never use supermarket fuel now unless I am desperate as I have proven to myself it is false economy.

Locally, BP seem to be waking up to this, as they are now selling unleaded at 117.9p / ltr, and diesel at 118.9, undercutting Sainsbury's by a noticeable margin.

[chris p bacon]

1978 and 16 years old I roll into the Texaco garage at the end of the road (A1) on my Fizzy (Yamaha FS1E)

 

"Gallon of 20:1 with 2 star please"

 

"Have you enough money" came the reply..........

[nick_bastable]

1978 and 16 years old I roll into the Texaco garage at the end of the road (A1) on my Fizzy (Yamaha FS1E)

 

"Gallon of 20:1 with 2 star please"

 

"Have you enough money" came the reply..........

about 45p from memory

[chris p bacon]

about 45p from memory

I actually thought it was nearer 80/90p but can't remember exactly.   20:1 was 2 shots of 2 stroke oil which must have accounted for 15-20p

[60159]

I worked part time in a garage from '67 to about '72 which sold Esso. The names pre-dated the star ratings. Esso was 2 star, Esso Plus was 3 star, Esso Extra (of which I still have the ceramic pump top) was 4 star and Esso Golden was 5 star. I recall the Shell ranking as Shellmex 2 star, Shell 4 star and SuperShell 5 star

[Kickstart]

I once accidentally filled my first minor up with 5*. Man did that make a difference, she flew on that tankful!

It shouldn't have done. If the fuel is a high enough octane rating (and presume what you normally filled it with was) then anything higher is of no benefit.

 

Think of it a bit like a fuse in a plug. Too low and it will pop, sufficient and it won't pop but no benefit.

 

Running old cars i always use branded as i need the anti Knock additives to protect my engines

 

You get them anyway. The anti knock additives are what gives you engine its octane rating.

 

I decided to see for myself, and compared several tank fulls of supermarket diesel with several tanks of Shell diesel - can't remember the exact name but it was the one they were promoting as giving better fuel economy.

 

I tried the same for my last MX5. Switched to Shell V Power (or whatever they were calling it that month) for a month (so 4~5 tanks of fuel) out of interest. It made no positive difference to fuel consumption (it actually used a tad more fuel, but within a reasonable margin for error) and didn't improve performance. I would say it felt slightly smoother at low revs, but nothing I could measure and possibly a placebo effect.

 

All the best

 

Katy

[SGP]

 

 

Some people still do, I know folk who won't use supermarket petrol because they believe it's inferior to branded makes.

My old man used to drive tankers for Mobil and the additives were added to the tank if delivering to a Mobil forecourt but there were no additives added if delivering to Asda.

[SGP]

At the Kingsbury fuel depot, Shell, BP, Esso, Mobil, National, came via pipeline from Milford Haven. Fina, Conoco, Jet, Amoco, and the like came by tank train from Immingham (Lindsey or Humber). 

The pipeline would deliver petrol and diesel sometimes with a pig separating the two, sometimes not. Diesel and petrol have different densities so much of the slop could be salvaged in the settling tanks. Trouble is, you can't get your product delivered this end without ordering more at the other end. 

Petrol is petrol to a point, the additives are added to make each brand unique .... Jet petrol I found, ran hot and mpg was never as good. There was an instance back in the mid 80's where Shell petrol with a certain additive had to be withdrawn because it was ruining engines (I was running an '83 Cavalier at the time which I bought two years old and sold after 18 months which gives me a rule of thumb on the timeframe).

[duncan]

The benefit of the E type and other cars running on 2 star was that many countries did not have 5 star, or even 4 star petrol.  Even if they did, it was usually only in the urban areas.  Not much use if you needed to fill up & the car couldn't run on what was locally available.  There are many parts of the UK (particularly the country) which currently do not stock 98 octane ( nearest equivalent to 5 star), and if they do, I would check how old the petrol is before buying it, as it can degrade with age.  

 

My TR6 runs quite happily on ordinary 95 octane petrol, though when towing the heavy trailer a distance, I often use 98 octane.  it does run better, smoother & accelerates better.

 

edit - agree completely that different makes of petrol have differing qualities.

[jjb1970]

Supermarket petrol is the same petrol as used by the branded oil company filling stations, it is the same quality, produced in the same refineries from the same feedstock. The branded fuel may have additives but may not and those additives may or may not be beneficial for engine durability but they're not intended to boost performance or efficiency. The additives tend to be more for the premium (97RON+ grades) than the standard 95RON anyway. Ditto with diesel, whatever scare stories there are out there diesel is refined to a common standard by refineries supplying all customers. The premium diesel fuels may have a higher cetane rating but as with the octane rating there is nothing wrong of "bad" about regular diesel. Engines are set up to run on standard grade fuels, whether there is any benefit from the premium grades is quite a contentious question. I sometimes run our Golf on Shell Nitro and to be honest don't see any noticeable difference in fuel consumption relative to 95RON fuel.

[Titan]

Supermarket petrol is the same petrol as used by the branded oil company filling stations, it is the same quality, produced in the same refineries from the same feedstock. The branded fuel may have additives but may not and those additives may or may not be beneficial for engine durability but they're not intended to boost performance or efficiency. The additives tend to be more for the premium (97RON+ grades) than the standard 95RON anyway. Ditto with diesel, whatever scare stories there are out there diesel is refined to a common standard by refineries supplying all customers. The premium diesel fuels may have a higher cetane rating but as with the octane rating there is nothing wrong of "bad" about regular diesel. Engines are set up to run on standard grade fuels, whether there is any benefit from the premium grades is quite a contentious question. I sometimes run our Golf on Shell Nitro and to be honest don't see any noticeable difference in fuel consumption relative to 95RON fuel.

 

 

I am sorry but I did a back to back test on supermarket diesel verses Shell diesel. I did not rely on 'noticing' any difference, I actually measured it. no ifs, no buts, or maybes, the shell diesel produced a measured 10% improvement in performance and economy compared to supermarket fuel. Did you actually measure the change or were you relying on 'noticing' it? It has to be said though that performance difference on diesel is likely to be more marked than petrol, as unless the petrol car is a high performance model that can take advantage of the better fuel it won't make much difference, whereas better diesel will make an improvement in every diesel car.

[russ p]

I know one thing my metro turbo pinks on supermarket fuel but not on branded

[great central]

I am sorry but I did a back to back test on supermarket diesel verses Shell diesel. I did not rely on 'noticing' any difference, I actually measured it. no ifs, no buts, or maybes, the shell diesel produced a measured 10% improvement in performance and economy compared to supermarket fuel. Did you actually measure the change or were you relying on 'noticing' it? It has to be said though that performance difference on diesel is likely to be more marked than petrol, as unless the petrol car is a high performance model that can take advantage of the better fuel it won't make much difference, whereas better diesel will make an improvement in every diesel car.

 

Totally agree with that. I've had diesels for about 8 years now, the first was an old Rover with a Peugeot engine, cost me £120 with 125k on the clock. Ran it at first on Sainsburys diesel (nearest supermarket) It was OK but when my son suggested using Shell instead, he'd had several diesels mostly Peugeot, it made a serious difference. The engine ran quieter, had more power, less smoke and was noticably more economical. When the head gasket went at 175k I replaced it with my current PT cruiser which constantly turns in around 50 mpg.

To give another example my son did some chauferring work using a Mercedes diesel (horrible uncomfortable car IMO), pretty much the same engine as my Cruiser I think. He could do Heathrow and back at a steady 70 or so and get near on 60mpg with Shell, Supermarket stuff gave at best 50 and often mid 40s

[russ p]

Managed to get the pump home today and also picked up a forcourt oil dispenser

The pump is to be restored to national colours as in the picture earlier in the thread and maybe a globe later if I can find a blank one

[uax6]

Photos Russ?

 

Andy G

[Guest]

Russ, can you turn the photo right way up? I've just turned the laptop upside down to have a better look and I'm embarrassed at the amount of crumbs that fell out of the keyboard...

 

Edit: Mmmmm. Digestive. I think. Might be HobNob...

[uax6]

That's an interesting one, I don't recall seeing one like that before. Is it an Australian import.....?

 

Andy G

[Kickstart]

There was an instance back in the mid 80's where Shell petrol with a certain additive had to be withdrawn because it was ruining engines (I was running an '83 Cavalier at the time which I bought two years old and sold after 18 months which gives me a rule of thumb on the timeframe).

That was Formula Shell from memory.

 

All the best

 

Katy

[jjb1970]

Fuel clearly has an impact on engine performance. If talking about how adjusting fuel quality parameters such as cetane and octane could allow engine designers to improve efficiency that is an interesting debate. The problem is that engines are designed and optimised to operate on fuels as currently formulated.

 

The premium fuels tend to have proprietary additives to clean engines. Petrol tends to have a higher octane rating and diesel may have a higher cetane rating (although interestingly not all premium diesels do). The additives may be effective at cleaning gunk out of the fuel injectors, valves etc, which will improve peerformance of a dirty engine. These additives won't do much for a clean engine. That benefit however can be obtained by running the occasional tank of premium as you do not need to use these fuels continuously to get the benefit of cleaning. And it is worth remembering that unless the engine is fouling then you won't get much of a benefit from cleaning additives.

 

In terms of octane (petrol) or cetane (diesel) then depending on the engine design and management system you might get some improved performance. Petrol is more likely to be useful than diesel, especially for some of the very highly blown high performance engines. In neither case does the calorific value of the fuel or any other key performance parameters change because octane or cetane is boosted. And it is worth keeping in mind that boosting octane and cetane can have effects elsewhere which means it is not as simple as just pumping the octane rating up. You can do that relatively easily by cutting petrol with alcohol, you also cut the calorific value by doing that.

 

In terms of diesel, a higher cetane diesel will have a shorter ignition delay, however engines are set up to perform well with standard diesel formulations. Having read an awful lot of technical papers on this subject and been involved in a lot of test projects myself I'm afraid I'm more than sceptical about the ability of a slightly higher cetane number to transform engine performance.

[russ p]

That was Formula Shell from memory.All the bestKaty

Austin rover actually wrote to all MG metro owners telling them not to use it as it was incompatible with their engines. I remember getting one!

[kevinlms]

Russ, can you turn the photo right way up? I've just turned the laptop upside down to have a better look and I'm embarrassed at the amount of crumbs that fell out of the keyboard...

 

Edit: Mmmmm. Digestive. I think. Might be HobNob...

No need to do that. On Windows at least, try Ctrl + Alt + various arrow keys & see what happens.