Fuel Grades

[rizla603104]

Hi guys. Have been a proud S4 owner for all of a month. Does anyone have a preference (or avoidance) of fuel and fuel stations? I fill up at Tesco's and find the fuel grade variable and noticably so.

[J400GED]

Morning Paul,

I would definitely avoid the supermarkets unless you had absolutely no choice - their fuel is cheaper for a reason, you say yourself it is noticeably variable.

I use either ESSO or Shell Super Unleaded.

Hope this helps,

Ged

[slewthy]

Paul, I was looking at this in reference to another post. Unfortunately, Shell has at least 5% ethanol added. Esso, it seems atm does not, at least in its 'super' unleaded.

[rizla603104]

I have the choice of BP, Shell or Tesco locally.

the ethanol - is that good or bad? Please excuse my naivety!

[slewthy]

Ethanol is a potential problem with engines built before 1996 (dont know why that watershed).

It causes excessive corrosion of certain metals and plastics.

Also, since the main source of ethanol is bioethanol, as the fuel evaporates, an unpleasant residue is left behind with the production of acetic acid amongst other things. Also, since drying ethanol is very expensive, fuels with ethanol have higher water content than those without - not good.

Companies are effectively committed to using this stuff because of recent regulations, added to the fact that there is a relative 'mountain' of bioethanol currently.

Solutions go from only using fuel with no ethanol; low ethanol or adding protectants to the fuel.

The protectant route will cost between £3 and £8 per every 50L and have to be added at fill up. I imagine the various car mags have been reviewing these products extensively over the last few years but since my car has been laid up, I havnt paid that much attention. I am about to get it back on the road, hence my interest.

I'm sure there is another thread on this somewhere here too.

Re your question, Shell adds 5% ethanol, Some BP ultimate may not; Tesco - at least 5%.

It seems that in the South West, Ethanol is in most fuels!

Edited September 18, 2012 by slewthy

[arbell9]

I use what ever is going and cheapest in mine. Have tried the expensive rocket fuels and noticed bog all difference. The car runs good on cheap stuff.

Older classics though should be wary.

http://www.fhmcsa.org.au/Assets/Modern%20Fuels%20(2).pdf

This lotus drivers club thread is informative on th subject of E5 and E10 supply in the uk.

http://lotusdriversclubonline.org.uk/index.php?/topic/943-ethanol-in-petrol/

[Chris Southam]

I could be wrong (like Simon I haven't paid that much attention in recent times) - I thought 5% was ok, it was the move to 10% that would cause us pre-1996 car owners a problem?

[slewthy]

Well, that would seem to make sense given the info on the LDC site. ALso, 5% seems to be the max in any of the super grades.

Anyone using additives?

[oneshot]

I use Tesco "Momentum" - 99 RON which I believe is the highest RON rating of the premium fuels.

Apparently has a max of 5% ethanol.

Full specification

[dodge1979]

I normally use shell v power, failing that bp ultimate. I have, out of.no other.choice, filled up with the Tesco premium once. It is known, from various rolling road runs on peoples Esprits that they do tend to run better with the higher octain fuels. You may not necessarily feel any great improvement in performance, but if set up correctly a smooth running engine performing efficiently is worth the extra and probably not noticed quid or.so per full tank of.fuel...

[rizla603104]

OK - so really the higher octane / premium fuels. I must admit - I filled up with Shell premium and it did make a difference to the running of the engine.

[Guest surferphil]

Shell Premium is not the good stuff, V Power is the better on the shell forecourt but not as high octane as Tesco Momentum.

I think all petrol contains 5% Ethanol by law.

Petrol is supplied by the nearest refinery; regardless of who owns the refinery or who owns the forecourt.

Petrol is supplied to the forecourts via tankers as a base fuel, where additives are mixed in to make each brand fuel (Shell, Tesco, Texaco etc) for the different pumps on the forecourt (premium, V-Power, momentum etc).

I use V Power but it's the octane rating you should watch out for as; the higher octane rating the more stable the fuel will ignite and burn in the engine, giving more power and less able to detonate.

[Bibs]

Have you noticed that Shell don't put an octane rating on v-power? The additives aren't very stable and octane decreases rapidly when under the forecourt in the stations tank.

[steve930]

A friend of mine who owns a well regarded audi tuning company carried out back to back datalogging on a audi s4 using all the main fuels here in the uk (looking for maximum turbo boost before detonation etc) He did this over a period of 6 - 8 months iirc.

His findings were that tesco and bp were delivering the highest performance, whilst also being the most consistant from different batches, One of the worst was shell !

This testing was carried out around 6-7 years ago, so things may have changed by now.

Thinking outside of the box, I wonder if supermarket fuel is less contaminated, seeing as most of their forecourts are quite new (new fuel storage tanks) compared to the traditional branded fuel stations. I do realise these tanks have a service life of 20 - 25 yrs but still just imagine how contaminated they could be in the latter years of their service life

[rizla603104]

All very interesting stuff. Our Tesco does have one Momentum pump. Thinking back, my TVR Chimaera had a preference for this - so I guess it makes sense. Mind you - it did also have a preference for being in the garage a lot too!

[B1 RMA]

There have been a number of tests carried out over the years some have been discredited as being sponsored by the fuel companies etc. As someone who has bought exotic Jap imports for many years I can confirm that things like the Pajero Evo and Isuzu Vehicross both real high performance SUV's ran like pigs on anything other than V-Power or Optimax as it was then. One other thing I like about V-Power is that it supposedly has good cleaning agents so I use it in all my cars just for that. One other thing I have been running my 'chipped' (remapped) Renault Trafic van for two years now and I know it has a deadly accurate fuel computer, I buy a tank of V-Power diesel after every four fills of Morrisons diesel and I record 43.7 mpg instead of the usual 42 mpg so you do get a very small improvement on mpg with the Shell fuel.

[slewthy]

One would think therefore that perhaps, as Bibs points out, one of the main factors needs to be the busy-ness of the forecourt - ie a high fuel turnover. Seems that high octane will soon degrade if left in their tanks. Mine you, same will be true for your car. ie only fill up when you are going to use it!

[B1 RMA]

Yes I read somewhere that it does degrade, I'm lucky our local Shell garage is quite cheap and used by a lot of the Jap import guys so imagine the V-Power must be fresh. I once said that I must have been a taxi driver in a previous life as I only put 25 litres in my cars so it always stays fresh but I did get caught out on the fuel shortages a while back.

[dodge1979]

V power is 98 if I remember right....it always used to say so on the pumps ive used around here..

[Bibs]

Are you sure?

Go and double check...

[SteveSmith]

Bibs - are you saying/suggesting that V-Power isn't all its cracked up to be and should be avoided ?? (I've just put £50 worth in my car...)

Back in the Optimax days, it was always the fuel of choice for performance car drivers so I'm just wondering what's changed ??

[Bibs]

It's fine, one of the best in fact as a premium fuel but Shell can't guarantee the Octane rating enough to print it on the pump.

The added detergents these premium fuels carry over supermarket fuels are worth it alone and they don't degrade, Octane rating is purely an indication of enhanced resistance to detonation so more boost! Run a few tanks of any high Octane fuel (I used to love Tesco 99, big flames!) and the ECU will increase boost as it has a knock sensor and knows how high it can go.

[SteveSmith]

So alternating V-Power and Tesco Momentum 99 should give you the best of both worlds - quality detergents from Shell and flame thrower fun from Tesco. Every little helps

[Bibs]

[arbell9]

http://en.wikipedia.org/wiki/Shell_V-Power

http://en.wikipedia.org/wiki/Octane_rating#Research_Octane_Number_.28RON.29

Lists quite a lot of petrols with their Ron rating