Lee

Does anyone know of the best brand ? I've heard that supermarket fuels are to be avoided at all costs and I use BP/Shell/Esso in that order of preference. Anyone read any horror stories (I seem to remember an internal paper from Shell that one of their fuels knackered engines quickly)...

Rob French

All turbo subs 89 on that run anything less than 96 octane fuel will self destruct in a matter of time. Trust me I own a shop and have seen it happen, the octane rating is the rating given to the ability to resist dotonation. Detonation will put holes the size of a twenty cent coin in your left front piston, destrouing your subbie donk. From experiance I know insurance companies wont pay out a cent. In Japan the average octane rating at the servos is 100. I order 105 octane race fuel in a 210 liter drum. It works out about 20 cents a liter dearer than pump gas, but I mix half/half race and pump gas, I haven't heard a ping yet in a year of owning the car, plus the smell of the race fuel out the exhaust turns me on. The cheap option is to always run no less than 96 octane and add a product 108 octane boost (black bottle not red) every third tank before refuelling. Hope this helped you and dont say you weren't warned
Regards Rob

AnthonyJ

I always try and use Esso myself. It always seems to provide the smoothest drive and the best acceleration although this is entirely subjective. I've also heard rumours that Esso petrol does quote conservative RON ratings (see other posts on this BBS). I must say though that I noticed the differences in fuel types much more on my old V6 Mondeo. Anyone else got a favourite fuel?

vanya gant

My favourite fuel is one that doesn't blow the car up. I hear much about premature death of cars through piston blowouts - possibly especially late STIs. But Intec tell me that this is nonsense!
From now on I'm using super unleaded - but then I can't always get hold of it. Does anybody know whether detonation is less likely if you don't thrash the engine to the red line? Sometimes i have no choice but to put ordinary unleaded in because many garages don't have super. Comments anybody? Should I really keep some super unleaded in the boot?

Rob

Rob F,

Correct me if I'm wrong, but you're telling us that a standard UK spec Subaru Impreza Turbo 2000 AWD should not be run on UK spec Premium Unleaded (95 RON)?

I assume, therefore, that Subaru's warranty department has very deep pockets, since they recommend that we use 95RON or above?

More details please.

Rob.

RobAnderson

I reckon it's a bit optimistic to be able to talk about favoured brands of petrol when it comes to Super U/L. More like grabbing whatever you can get. In Harrogate,(nearest large town- no chance of S/U/L in rural garages-),for Super U/L it's a choice between one Esso garage and two Shell garages out of 20+ garages in the area and half the time you find that they've sold out so that you have the ridiculous situation of chasing half-way round North Yorkshire from town to town-which isn't cheap in an Impreza- looking for the holy grail that is Super Unleaded(usually with similar futility).None of the supermarkets sell it anymore and each time a new garage opens or existing one has a 'makeover' invariably they fail to sell S/U/L.
It's a pain in the **** basically and the time is fast approaching when I'm going to have to start carrying a bottle of the above mentioned octane booster around with me so I can safely fill up with the standard ****-water.

Now I've had my rant, I'll get back to the original question.Received wisdom appears to be that supermarket/budget fuel in general is of significantly inferior quality to the mainstream brands and whatever money may be saved in the initial 'fill-up' is soon offset by the lesser mpg and sometimes poorer engine running/performance that you get running on the cheaper fuel.

Bob Rawle

With my previous car, a Vauxhall turbo, I found that Esso unleaded was the best of the normal stuff. I noticed a significant improvement over all other brands. As far as SUL I can't say I've seen any real difference. My local garage has just stopped selling 4 star and all the pumps that were four star are now sul. Its BP at 81.3p per litre. Location malmesbury North Wilts. I'm still relatively new to Scubies so haven't tried many different brands yet.

Bob

MY95 5 door Sti, K&N panel + Fujitsubo Legalis Ti exhaust.

Pavlos

here in Cyprus we cannot get SUL. Regular unleaded is only 92 RON, and it seems like driving a snail with that petrol. However I will take the catalyst off and change to normal Super petrol 96 RON, since there are no MOT inspections.

Lee

Firstly,,I'll be changing to Esso for a while since that's 2 recommendations !

Secondly, I'll agree that you can only be doing a good thing by running SUL, but engines destructing running on 95RON ? As Rob says..subaru warranties must be sitting on a time bomb..

since mine is a company car I'll be knocking up around 40K a year, I'll let you know how long my motor lasts !

Thirdly, I've spoken to many tuning "gurus" - they agree that "Octane Booster" is a gimmick. The RON rating is a "purity" of fuel..unless you have a refinery you can't make 95RON purer. What you can do is add more bang...

StewartW

I use Esso SUL in my MY95 WRX. I have found that it tends to have a smoother response and is less lumpy at tickover. Also, it is only 81.9p/l compared with the other brands at 83.9p/l

RobAnderson

A couple of points:
Pavlos, I'm assuming that 'Super 96 RON' is leaded- in which case you are likely to run into long term problems with the Lambda sensor. Over time the sensor becomes coated with lead and is consequently unable to read CO levels accurately and thus causing your engine to run very badly.
If no unleaded petrol of a higher octane rating than 92 is available then you are also likely to have to use an octane booster to prevent detonation.

I need Super U/L because of the car operating at a higher than normal boost level and were I to use 95RON I would have to drive with extreme circumspection- unless I use an Octane booster to raise the Octane level and prevent detonation.
True,it doesn't improve the purity of the base petrol but for that reason I would stick with Shell or Esso (as I mentioned earlier, with S/U/L, I don't have much choice) because the quality is superior.

I do prefer Esso S/U/L -when I can get hold of it.

ColmanC

Just to clear up what seems to be a little bit of confusion...

There have been reports of STI's imported into the UK which have had severe engine problems probably caused by running on 95RON normal unleaded petrol. For STI owners, using Super Unleaded is recommended.

There have been no (as far as I'm aware) problems for UK-spec turbo owners (215BHP) running on 95RON, so Rob, your car should be OK

Colman

P.S. It's a bit confusing that this thread has posts from THREE Robs and a Bob !!!

RobAnderson

Sorry Coleman I neglected to mention, mine maybe a u.k. spec but it's running at 17psi(standard is 12psi),and thus is in a fragile state of tune as regards sub-standard fuel. I use S/U/L out of necessity.
You're quite right though- standard u.k.spec=95RON minimum (although, as pointed out on previous threads,S/U/L is certainly of benefit-especially if the engine is re-initialised- or just a tankful every so often to keep the engine sweet.) and Pete Croney recently pointed out that a few STi's have holed pistons after having been run on 95RON(designed to run on 100RON for maximum power- and minimum 98RON for survival)

RobAnderson

Doh! You're right about the confusion Colman,I've just realised you were referring to other Rob as being okay to run on 95RON fuel, not this Rob. Sorry,ignore first part of my previous contribution.

Nick

Even though the filler cap on the UK car says Super UL only - normal UL is fine as UL is called Super in many Euro countries. If you have an STi, or prodrive car, you should be using SUL.
I use SUL in my standard UK car as I feel it gives me a little extra performance.
Only one garage in my local town seels SUL - so I use that (BP). I am usually happy to use any major brand - Esso, Shell, BP & maybe Texico.

Mike Tuckwood

1) Not a detraction from the thread but what octane rating is normal 4 star?

2) If I remove the cat's which I would like to, do I run my MY93 WRX on SUL (as I do now) or 4 star, or either?

Rob (Anderson).
Had you been on a heavy drinking session prior to posting yesterday?

Mike.

Steve Wilson

Questions for Pavlos -

How do STis get on in Cyprus using 92RON ? I understand that STis are available officially ?

RobAnderson

Mike, The problem was that I was just starting to sober-up when I wrote first part of previous entry.My reasoning was clouded and it took a couple of slugs of meths to make me realise my foolish error and dawn on me which Rob I, in fact, was.

As regards your query re. 4star,I believe that is similarly 98RON (though I might be wrong) and while it is tempting to use this ,sans catalytic converter, on the basis that it's a bloody sight cheaper than S/U/L and ,for the time being at least, more widely available, it will,in the long term, **** your lambda sensor,'cos it gradually coats it with lead.

Pavlos

Steve, I've had my Impreza for just two weeks now, so I'm fairly new to this quest for higher octane fuel, however it seems that most of the Japanese imported Imprezas have the catalyst taken off and just run on premium leaded which I think is either 96 or 98RON. I don't know of any long term effects they might come across though Rob Anderson pointed out there would be a problem with the lambda sensor. The official Subaru dealer, says "use what's available and the car will adjust"...which I think is a joke!!!

RobAnderson...any recommendations on what octane booster I can use???

yee_har

Hmmm...S/U/L freely (you know what I mean!) available up here in the land of the turbo-haggis.

Lambda Schlambda - kinda makes one pine for the good old days of twin Webers, "points" and a pull out choke ****.
Then again...

Webmaster - maybe an "Old Timers" section to widen this to "What happened when 5* was phased out?"

RobAnderson

Pavlos,
There aren't that many octane-boosters currently available and I actually haven't had the need to use one yet- though there are quite a few 'gimmicky' fuel additives that might mislead you, and beware of ones containing lead.
The one that springs immediately to mind though is 'Silkolene Pro-Boost'.This has been developed and used in competition (Will Gollop used it in his Peugeot306 Rallycross car to enable it to safely produce 635BHP using an ex- BMW F1 Turbocharger that can run in excess of 5 bar boost- a standard Impreza runs at just over 0.8 bar-,so you get the idea- it's the real stuff).It's also completely lead-free.
I don't know what sort of access you have to motorsport accessories, but you can get the stuff from Demon Tweeks(export tel.no +44 1978 664461 or e-mail- sales@demon-tweeks.co.uk) who, I understand, will deliver anywhere in Europe. It costs £7.26 for a 1 litre bottle(though I don't know what the ratio is of Octane Booster to fuel is.) +postage and packing charges.

Daniaxeman

iTrader: (1)

i have a uk spec turbo 2000 wagon and top up on 97 + octane fuels. im getting a little tired of my bother telling me im wasting my money and it would be fine on 95, can i confirm that he is wrong so i can finally put this argument to bed

i did top her up on 95 for the first couple of months until i was told id ruin her in the future and since then ive noticed an improvement in mpg - can anyone else confirm this? i had a 'grandad driving month' last month and managed 36.7 mpg! this is compared to the 20-25 i was averaging before on 95 oct

marcevs72

iTrader: (5)

i use tesco momentum in my 93 jdm wrx and runs spot on.i was recentely told by a subaru specialist that the first imprezas in japan were run on 95-97 ron fuel as 100 ron wasnt available at the pumps and was bought in cans as race fuel so early cars can run british unleaded at 95 ron....
but as we all have tweaked our cars the added protection of higher octane fuel from det is worth the few pence a litre extra(i can get 99 ron momentum for £1.35 a litre where i live.my last 97 uk impreza was running loads of mods and ran fine on 95 or 97 ron fuel.

P1Drifter

iTrader: (7)

Daniaxeman

iTrader: (1)

Atm I'm running a standard system due to financial ties but still prefer to use 97 RON incase of det.

Does anyone know if mpg improves with grade?