Senior_AP

If you have an Impreza (or any other decent car) use decent fuel.

Trial and error between Optimax, 97 and 98 RON. Whatever your particular car works best with; use.

It costs more for a reason - you get what you pay for.

OH YEAH - - - - "CORNER"...

....OR WHATEVER ITS CALLED. ERR, YEAH.

[Edited by Senior_AP - 6/4/2002 3:43:13 PM]

planky

Devils refugee,i dont think in europe they have high octane fuel(except france etc etc etc etc),im sure they have only low octane fuel(95ron)dont quote me on that one!!!!
we are lucky we have optimax(98.5ron)thanks Shell.
Disclaimer-- what i say might not be fact!!!!!!

[Edited by planky - 6/4/2002 6:09:47 PM]

IanA

Totally unscientific but just started using SUL. On the second tankfull my regular trip to London cost just over £11. With NUL it was always over £13. Obviously that's all motorway, around 75-80. Pick up seems to have improved too. I'll be sticking to SUL or Optimax from here on. BTW I refuse to buy petrol (except for very small amounts in extremis) from motorway services. What a ******* rip-off.

PS My girlfriend says I am an anorak for even noticing/knowing about these things.

[Edited by IanA - 6/5/2002 10:59:45 AM]

robb virgo

as above ,
is any one stupid enough to do this over in england ???.
people tune their cars and dont realise that extra safety and power can be got from running the correct fuel.
also a myth that octane boosters work exists, i spoke to several tuners and they all dismiss these products.they wont stop detonation..... goodby piston tops !!!

a lot of scooby / cossie drivers over here are using 95 u/l as super is v hard to get ( i have only found one garage in the whole of cork county) and i think we should campain to get the suppliers to provide more outlets.
what does everyone else think ???

Devil's Refugee

Shell should be pumping out Optimax fuel in England. Much better than 97Ron SUL apparently (read EVO on the test results)

We're still waiting for the miracle fuel here in Scotland but it's supposed to be on it's way soon.

But I use SUL as a rule of thumb.

davyboy

I use normal unleaded at times.

UK Spec MY01.

Do be honest I cant tell the difference.

clubby

Same as Davyboy, MY01 UK model, cant tell the difference in performance. You cant always get SUL round here.

robb virgo

davy ,

i think that the computer detects 95 u/l and knocks back the timing.you will be running less power now even wuth 97 u/l until you reset the computer.

i think this is right ...any experts to correct me ???

Senior_AP

Decent cars should really have decent petrol in them.

Imprezas should really have super or Optimax in them. If you change from Crappy unleaded to Optimax and back again all the time the car has to adjust constantly. This probably isn't good.

If you can afford a Scooby you should be able to afford decent fuel. (unless it isn't available).

Scooby Dooby Blue

Robb Virgo

I'm not an expert but AFAIK, the MY01/02 scoobs learn the knocking point at every ignition without taking into account previous levels.
The classic scoobs run on an average whereby it'd take an infinite number of ignitions to re-learn the point using 97ron after a tank of 95, which is why you'd reset the ECU.

This is just what i've heard

Paul

JackClark

I had to put a tank full of Normal Unleaded the other day, ran like a pig. Now back on Optimax and she seems to have survived the ordeal.

chrisp

I think you are wasting your breath I keep telling people to run decent fuel but give up now as they always know best and its the easiest modification I know .

Boost II

iTrader: (1)

I have recently become an Optimax convert - everything feels so much smoother - its not just to do with higher octane rating but its cleaning properties too. Never rated 97 RON super over 95 RON normal unleaded in my UK Impreza - if anything I could feel some slight hesitations and things I could not detect with the 95, no noticable difference in performance or fuel economy either. Optimax however definately feel faster.

STi wanna Subaru

iTrader: (1)

I had to put some NUL in the other day as the Shell garage had run out of Optimax. The car (MY99 Uk Turbo) didn't run anywhere nearly as smooth as it does on Optimax.

Haggistrap

I always try to run optimax or SUL, but the last tank full I put in was normal UL, due to being the only fuel there and I did not want to push her home!

The big question is does normal UL really damage your car? If so how?

My car is an MY98

Scotsman

iTrader: (3)

I always now run SUL in UK MY99. Can't say I have noticed anything major/minor with regards to performance but I do get better mpg - which actually makes it cheaper to run.

Richard.

chrisp

On a Uk turbo you can use 95 NUL as the ECU is designed to react to 95 RON fuel. The ECU retards the ignition until its safe for use with the fuel. This means that if you run better fuel the ignition can run in a more advanced state. So running SUL or Optimax in a UK will at worst make the car run smoother through the rev range and pull better and at best give you a few extra horses . Well thats the theory

On a grey import the ECU was not designed to retard to use 95 RON fuel and this is when problems occur and engines sometimes go bang.

Boost II

iTrader: (1)

UK cars are perfectly safe to run on 95 RON, but not Jap imports (they are designed for 100 RON fuel) - it all depends on how the ECU is programmed.

STi wanna Subaru

iTrader: (1)

How quickly will MY99 ECU adjust to the NUL from running on Optimax. If for example you drove for a few miles and then booted it, could this cause any damage?

skiddusmarkus

Basic rule,if your car is et up to runon 100octane and you HAVR to put ul in it then don't drive as hard and keep the car at lower boost levels.I've heard loads of people reckon it's ok to use ul in their import cars to save a few quid-they're miossing out on performance and risking their engine.
As for octane boosters,I can only speak from my own experience of using them for about 2 years-my car DEFINITELTY runs better with them.It revs more freely and there's more torque.The boost guage confirms this as it will actually boost less(a couple of psi so 10-20bhp) on the very few times I've not been able to use sul or optimax.

skiddusmarkus

Must type slower or use spullchacker

wacky.banana

Always run my MY00 on 95UL on the recommendation of the dealership. Never had any problems. There again mine is a UK spec car so the ECU takes care of things.

To gain any advantages using 97RON you need to get the ECU reset at a dealership, fill her up with 97RON beforehand, find an empty road and boot the life out of your car. What that does is to get the ECU to reset itself so it knows where the new knocking point is. Problem is if you go back to 95RON then the ECU will retard itself (to protect the engine) and you may experience some problems, eg hesitation.

Anyone using an import has to be careful because the ECU's are set for 100 RON.

My view is that a sensible remap is the best way forward on these motors but each to his or her own.

HTH

WB

BlueTrap

Apologies for the sidestep..... and the silly question but here goes...

A PUG 96 xsi 306 8v running unleaded.... Optimax is that an alternative to straight 95 green???

I would like to obtain a cleaner engine but am a little concerned about the push home problem?

Please any help would be appreciated!

Wurzel

iTrader: (1)

I run 98 ron in mine all the time as it is cheep out here, when I come to the UK I try to run 98 aswell , I found if I run on 95 for more than 1 tank my car sounds like a VW beatle and is sluggish.

I don't know if mine is setup differently to the UK Cars but most people in the UK seem happy to run on 95.

Devil's Refugee

Blue Trap

In the recent EVO test on fuels (last months issue I think) they tested different cars running on a variety of mixes throughout the cars life (ie Civic Type R, Jag, Beemer M Z-Coupe, all either running on SUL, NUL)
They checked the internals for crap and inlet conditions, then ran them exclusively on Optimax.
For once, it would seem, there is a fuel which lives up to it's name. The cars all responded better to the fuel in terms of performance and the internals were all checked again after a 2k run with the fuel. The parts inspected were visibly cleaner.

I've yet to use the stuff (still on SUL. I'm in Scotland, so still waiting for Shell to get the finger out) but rest assured my Scoob will be treated from Day 1 onwards to Optimax.

I shouldn't envisage problems with your Pug mate. It's a higher rating of fuel (98 Ron) so should give better detonation and performance, and will clean it up along the way.

Oh, and avoid Supermarket fuels. They're crap.

Hope this helps.

AndyC_772

iTrader: (2)

Did that Evo test on Optimax read like an advert to anyone else besides me?

Robb: I've just come back from Ireland after taking the Scooby (MY00, UK spec with PPP) over there for a couple of weeks. I made a point of filling up with Optimax, my usual fuel, at Swansea before boarding the ferry.

After a few days I ran out, and had to fill up with 95 RON fuel, for the first time since having the PPP fitted. My engine immediately became rougher and felt asthmatic, and was definitely lacking in top-end power. The spec for the MY00 PPP does say that 95 RON fuel is safe to use but results in a power reduction, and I'm inclined to agree.

Needless to say, I'll be heading straight for an Optimax pump as soon as my tank's empty.

Before fitting the PPP, I did have to use 95 RON petrol once before, during the fuel crisis. At that time, I didn't feel anything like the same difference - it was maybe a bit rougher at very low revs, but really not that bad. Seems like the Prodrive ECU really does need SUL to give its best.

Andy.

Devil's Refugee

I got a bung from Shell !
;o)

BlueTrap

Devil - Do I need to have any extra's or conversions performed on my pug to run the Optimax or can I just fill from empty and race away.....

Devil's Refugee

B-T,

I wouldn't think so.
If you're in Europe (Netherlands?) then you could be running with a higher rated fuel than us here in UK (97Ron as standard ????)

I'd run with SUL (97Ron) for a couple of tanks first to see how you get on. Then try a full tank of Optimax. If you get no probs, keep using it.
It should clean up your engine like you wanted.

(it's at this point I post a disclaimer.....!)

p

Devil's Refugee

How the 'eck did that smiley appear ?!

I can never get the hang of them.

Can anyone shed any light on 'em ?