supermarket fuel

[Dan n Nic]

Why then do some car manufacturers including VW will state not to use supermarket fuel?

Who do you think they develop the car with?

They aren't going to nip down tesco and buy 500 litres of unleaded to test the engines on are they.

I would it's cheaper 

Are there not different "grades" of fuel though?

[Adam]

I know for a fact the fuel coming into Avonmouth, Bristol get distributed to BP, Shell and Tesco in the south west. All contain the same fuel but you will pay 15-20ppl over Tesco prices at some forecourts.

[The Mighty Elvi]

All fuels must conform to British Standards. Hence the BS 95 RON on the pump. Petrol is the same but individual retailers may add their own "additives".

[Luke1981]

Thanks for the info lads

[Agreeable Slick]

Why then do some car manufacturers including VW will state not to use supermarket fuel?

Who do you think they develop the car with?

They aren't going to nip down tesco and buy 500 litres of unleaded to test the engines on are they.

I would it's cheaper 

Are there not different "grades" of fuel though?

Yes 95 98 & 100.

Don't believe the hype, additives do not make it a different grade.

[Agreeable Slick]

It comes out as 95 through fractional distillation and cracking. Ethanol or Methanol make it stronger normally.

Additives are usually a % of antifreeze, or in diesels case a non emulsifying agent.

Good enough for you?

[The Mighty Elvi]

FYI Tesco gets its fuel from Greenergy.

[DOA]

It comes out as 95 through fractional distillation and cracking. Ethanol or Methanol make it stronger normally.

Additives are usually a % of antifreeze, or in diesels case a non emulsifying agent.

Good enough for you?

I wasnt having ago mate, just curious is all 

So if i put methanol in my tank it would increase the octane?

Yes but its aggressive stuff and can you remember the last time you saw methanol to buy in your local garage. If your engines not optimised well enough or adaptable enough though, theres not much power gain and the economy goes down as there isnt as much energy in alchohols as there is in petroleum, A lot of countries use weak ethanol blends, Thailand, USA etc etc and their cars need to be optimised because of the aggresive nature of the fuel. Wierdly its not as aggressive and doesnt affect rubbers and metals in much higher doses so not such a problem with E85  . Guess who's been looking into E20 fuel and its effetts on fuel pumps and rubber hoses all week at work  .

[Agreeable Slick]

@ wolf boy: Not quite, they are blended together before being sent out.

Methanol is actually quite agressive towards metals. Acetone is blended in as well to help it mix.

Basically, don't do it. You will break stuff.

[Organisys]

Not again!!

A Higher octane rating in petrol is a measure of the fuels ability to resist pre-ignition due to compression.
I.e pinking, The fuel partially exploding on the compression stroke before the spark Plug has been able to fire.

An engine can obtain more power from the fuel if it can compress the mixture more before it ignites it.
Hence higher Ron fuels mean the engine can retard the ignition timing and develop more power as a result.