Shell Super unleaded

MEM62

Car_54 said:

Some might say ... they probably think anyone buying "Super" petrol has more money than sense.

Or they have older motorcycles where, due to occasional use, the tank is not emptied / refilled regularly and the fuel lines are degraded by ethanol.  

Goudy

Diesel fuel is rated by cetane.
This is a measure of combustion speed.

Lower cetane diesel tends to burn slower than higher cetane diesel.

Generally higher speed diesel engines like the ones found in cars run more effectively on higher cetane fuel, but your average diesel car, van or lorry will be designed and programmed to run on the fuel available in the markets it's sold in.
Typically 40 upwards, though our EN 590 should be around 46 to 51.

But saying that, I tend to notice less engine clatter with higher cetane diesel.
Never noticed any more mpg though.

It's easy to improve the cetane number of diesel, they just add 2-ethylhexyl nitrate.
Most diesel fuel additives some owners feel compounded to add to their fuel will be made up of various levels of this 2-EHN.

Unlike "Super or Premium" petrol which have a higher octane ratings than standard unleaded, Super or Premium diesel doesn't always mean it has a higher cetane rating than regular diesel.
Some do, some don't.

kingstreet

My 1999 Saab 9-5 (3.0 V6 Turbo - B308E engine) is designed to run on 98 RON super unleaded. I've used that for pretty much the 17 years I've owned it. I've occasionally used 95 only where I couldn't get 98. It has 227k on the clock and the mechanic who cares for it says it should be good for at least another 100k, parts availability permitting.

Stateofart

Nobbie1967 said:

Many cars are recommended super unleaded, but run fine on regular as they can adjust timing if they detect any issues. My old Boxster was one such car. Ran it on super for the first few fills, but then couldn’t get it for the next fill and used normal. Noticed no difference in performance or MPG. Put 25k hard miles on it and it never missed a beat.

On some cars it is critical, but they are few and far between. My manual says use super for optimum performance, but regular can be used safely. I’ve heard some say they get better MPG with super and that this makes up for the extra cost, but I didn’t find this.

Correct.  Japanese performance cars often need 99 Ron.

kimwp

It's not enough to reverse the damage to the climate.

Bigwheels1111

Goudy said:

Diesel fuel is rated by cetane.
This is a measure of combustion speed.

Lower cetane diesel tends to burn slower than higher cetane diesel.

Generally higher speed diesel engines like the ones found in cars run more effectively on higher cetane fuel, but your average diesel car, van or lorry will be designed and programmed to run on the fuel available in the markets it's sold in.
Typically 40 upwards, though our EN 590 should be around 46 to 51.

But saying that, I tend to notice less engine clatter with higher cetane diesel.
Never noticed any more mpg though.

It's easy to improve the cetane number of diesel, they just add 2-ethylhexyl nitrate.
Most diesel fuel additives some owners feel compounded to add to their fuel will be made up of various levels of this 2-EHN.

Unlike "Super or Premium" petrol which have a higher octane ratings than standard unleaded, Super or Premium diesel doesn't always mean it has a higher cetane rating than regular diesel.
Some do, some don't.

I have to agree with you on how much quieter and smoother my diesel is on start up.
After I started using Mannol 9955.

Goudy

That's because Mannol 9955 is around 30% 2-EHN.
Some hydrocarbons as a "carrier" to stretch it out.
And some perfume (usually naphthalene which is also used in moth balls).

When I was making my own diesel from used cooking oil, that tended to be quite a bit lower in cetane are regular pump diesel,  I used to buy 2-EHN in litre or 5 litre containers.

It should work out far cheaper than proprietary diesel "enhancers" that tend to cost more for less.

You only need around 1ml per litre, so one litre of 2-EHN should enhance the cetane of 1000 litres of diesel by around 4 points, so will turn 46 cetane fuel into 50.

Back then it cost around £10 a litre, so a penny a litre.
Today I think you're looking at £15 to £18 a litre or 1.5p to 1.8p a litre.

As your Mannol is only around 30% 2-EHN, you need over three times as much to treat the same amount of fuel to the same effect (3333ml for 1000 litres) and it costs more, around £20 a litre.


There are other, cheap off the shelf ways to improve cetane that have been used and tested, but they are no longer considered viable for modern common rail diesels due to things like zinc in them, which can accelerate wear of modern, high pressure injector nozzles.
They were perhaps a better option for older diesels so best left on the shelf these days.

Attican

born_again said:

chess_010 said:

I have found that the price of super unleaded varies widely but is largely too high and does not come down when normal petrol does
i found usually in Cheshire 164.9 today for shell super unleaded but in fife scotland I paid 154.9 last weekend for shell super unleaded with unleaded I think 144.9 in cheshire
why the vast difference ? And why does not come down when normal unleaded does?

E10 was cleared for use on cars in 2000. So not really many cars that will not run on E10.

As to why costs vary.
Because they can. Often price are a game of cat & mouse between local supermarket stations.

But shell & BP round here are at least 10p ltr dearer than supermarkets...

To be sure “All new cars manufactured since 2011 are compatible with E10 petrol, and most cars and motorcycles manufactured since the late 1990s are also approved by manufacturers to use E10”

From here.

https://www.gov.uk/guidance/e10-petrol-explained#compatibility

My 2007 car requires E05.