Shell Super unleaded

subjecttocontract

I'm probably one of those people who doesn't bother much about the price of fuel. I drive around 3000 miles a year, I usually get over 50mpg so I only buy approx' 60 gallons a year. If I pay another £1 to top up my car it really doesn't bother me at all.

What does annoy me is the price of a weekend FT......over £5.....now that's taking liberties.

Nobbie1967

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.

pseudodox

Car_54 said:

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

My regular garage, motoring organisation and a friend who is a lecturer in Mechanical Engineering all advised me to use E5 in my 22 year old car.  I don't do a lot of mileage and I do get slightly more mpg than I used to before E10 replaced standard petrol.  It is annoying to have to pay so much more per litre, but the extra mileage compared to the reduced mileage a friend who uses E10 now experiences just about evens out.  Not worth saving a few pennies on fuel to run up a repair bill on the car.  My local fuel is Texaco - tends to be pricey - but if I drove a few miles I could get it cheaper at the Tesco superstore.  However the saving would be eaten up by driving those miles which are not my usual route to anywhere.

motorguy

njkmr said:

I use Costco for fuel. 
Think it was £1:40 for the super unleaded equivalent.
They have two octane levels.
Used to be 90 or 97. Not sure if it dropped to 95 for the super unleaded stuff, but I put it in my cars and they run well.

Theres a difference between premium fuel and superunleaded fuel.

Super unleaded will always be 97 RON and E5.

LightFlare

My previous car got ~10% extra mpg, was def more responsive and ran smoother with super

I used to fill up with it about 1 in 4 or prior to a long journey. The difference was noticeable (as was the cost)

(edit). Pretty sure there was a segment on 5th Gear (when it was good) about premium fuels and their benefit (or not) many years ago

XzavierWalnut

Very interesting YouTube video by Conquer Driving called E5 or E10.

oldagetraveller1

I buy E5 for my 60+ years old Classic. Saves removing the Ethanol from E10, plus it runs better on the higher Octane Rating.

The cheapest E10 for my daily car though.

Mildly_Miffed

motorguy said:

Car_54 said:

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

My car requires it to run optimally.

As do many cars.

Its sensible to use the fuel the manufacturer advises.

I very much doubt there's anything been sold on the UK market since the early 80s that REQUIRES the extra octane.

There have been cars sold that can make more power on it, especially turbocharged ones, but that's a different question. A base engine management map that sets boost and ignition for the higher octane, but will set them safely if knock/pinking/pre-ignition is detected. So the difference is only one of whether you need/use/will notice that extra power. If so, I suspect you are not driving in an appropriate manner for the road...
The manufacturer almost certainly gives a lowest-recommended octane value, quite likely 91RON, so everything above that is just fine.

Then there's the ethanol content.
Yes, there's a VERY slightly lower calorific value (energy content) for E10 than E5.
E100 has roughly 70% of the content of E0, so E5 (the standard since the launch of unleaded nearly 40 years ago) would be around 98.5% of E0 and E10 about 97%. Again, such a small difference as to be irrelevant to fuel consumption. Certainly nowhere near as big a difference (1.52%) as the difference in cost per litre (rarely under 10%, often nearer 15-20%) of premium and super.

The difference is a vanishingly small proportion of the overall efficiency of the average petrol car in turning the fuel's energy into motion - typically about 30% at absolute best.

The UK was really, really slow to E10 - most other European markets had it as the default a decade before us.
All cars sold in UNECE markets since 2009 must be compatible with E10, and quite a few older are, especially where they've also been sold in the US, since E10 has been the standard there since the 70s.

pseudodox

The advice I received re E10 v E5 has nothing to do with the efficiency of the fuel.  Ethanol can corrode rubber, metal, and plastic parts in the fuel system, which can lead to increased maintenance costs.  I was advised that if I want to use E10 I should only put a limited quantity in the tank that I was likely to use quickly as if it sits there (as my car does often these days not go out much) the moisture absorption properties of E10 would be potentially detrimental.

I would rather take advice from the professionals I consulted than random strangers on a website who don't drive old or classic cars.

After using E5 long enough for residue of previous fuel to have been cleared I also found my aged motor felt like it had a new lease of life as it seems to run smoother - like when I have taken a dose of cod liver oil.

born_again

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...