Scooby_Snax

Just reading the thread about optimax vs. esso 97 etc.

I run an MY00 classic turbo with no engine mods. I feed it normal 95 unleaded. I'm happy with performance. Damn site better than the old Clio

Can I assume that most people here run tuned engines/PPP/STi which require the extra RON 97-98 or am I risking damage using plain 95?

SIDC FAQ suggests using 95 for the classic. Are perceived performance benefits worth the extra cost if potential engine damage is unlikely?

This has probably been asked before I guess but just a simple 'OK' or 'Must be Mad' will suffice.

Regards

Bubba po

Go for it. There's no reason why you shouldn't. I like to use Sainsbury's 97 because it's the cheapest higher octane fuel near to where I live... 81.9p/L at last fill up.

GREEN SCOOBY

YOU MUST BE MAD!

The right petrol is a must on these cars.
Your car is actually mapped for 97/98 ron petrol (see your manual, or maybe inside your fuel filler lid there may be a sticker) so it is best to use that type of fuel. The uk cars are not as bad as the jdm motors as they have a different map so there for can run on 95 ron better than a jdm (jap cars are mapped for 100-102 ron) but using 95 ron I suppose will be ok as long as your not giving it some speed but seen as though its a scooby you will be doing just that so its no good really. A couple of other points as well is You will also find that by using the 97/98 ron you will gain extra power and people with the knock links can tell you on this bbs if they are getting det by using optimax or other sul so if you are using nul you will almost deffinately be getting det when pushing hard. I briefly worked out before that filling up with nu compared to sul for a whole tank was maybe around £3-£4 more so its worth it mate.

hope this helps and some of it sounds alright and I remember anything in the morning after a heavy sesh

Iwan

If yours is a UK turbo and doesn't have PPP, then running on 95 won't do it any harm. However if you run it on 97 or 98 (Optimax) then you might find it runs better/smoother, or you get marginally better MPG.

Quite a few people have reported that they get a few extra MPG running on Optimax, which means the extra price doesn't make much difference.

Optimax is supposed to make your engine run cleaner (according to Shell), so there could be long term benefits to using it (other than more power or MPG).

wide

Now then when it was released here it was designed to run on the petrol we get and nothings changed, normal unleaded is fine

Scoob99

iTrader: (1)

When I bought MY98 UK Turbo I was told by the Dealer that I did not have to run it on Optimax, That was 4 years ago and mine runs beatiful
Cheers
Colin

Iwan

Exactly, unless it's PPP'd you don't have to run it on 97/Optimax. But quite a few people on here have done their own little experiments monitoring average MPGs over a few weeks, several have posted that they get slightly better MPG over 95 unleaded.

Using Optimax or BP Ultimate should allow the ECU to use more ignition advance (it's adaptive within a certain range) so in theory you should get a tiny bit more power. Again in theory, the above two fuels contain detergents so should prevent your injectors/valves/plugs getting blocked/coked over the life of the engine.

GREEN SCOOBY

Mmmm! you learn some thing new everyday. Sorry scoobysnax if I posted the wrong info, its just that my car has a subaru sticker on the inside of the fuel filler cap telling me to use 98 ron petrol only!

GC8

Does it say 'Use 98 RON Unleaded Gasoline Only'; or dies it say: 'Use Premium Unleaded Gasoline Only'? The reason that I ask is becasue 'Premium Gasoline' doesnt mean the same thing in every market.....

Simon

chrisp

Back in 1998 when I picked up my first scoob I was strongly advised, by my dealer, to run on superunleaded fuel, as the ecu can take advantage of it and the car will run better on it. That was a standard MY98 uk turbo btw. If you can get hold it, run it on optimax.

DEEDEE

I have a standard MY99 UK Scoob and run it on Sainsburys Super unleaded. It runs better/smoother than if I put normal 95Ron in. Put some JET in last week it was S**t lumpy and no go.

ozzy

A MY99/00 UK car will run fine on 95 NUL. It's advised to run it on SUL to gain the most performance out of the car.

My manual states 95 RON or better. Super Unleaded Gasoline is for non-UK markets where Unleaded and Superunleaded equate to lower RON values than here in the UK. IIRC Unleaded is 90 RON and Super Unleaded is 95 RON in some countries.

Edmondo

When I picked up my MY99 Turbo the guy at the garage was most insistant I ran it on SUL /Optimax.....Mine has no mods done by me but not sure about previous owner....

Scooby_Snax

Thanks for the advice. I'll give some SUL a go. Likely to be ESSO as no Shell station within several miles. However - without the fabled ECU reset how many tanks do you think it would take before I could draw any conclusions?

BTW Edmondo - your insurers may wish to know if the previous owner made any engine mods!

GC8

A Ph1 Classic ECU only retards it doesnt learn, so no reset, no improvement

New_scooby_04

iTrader: (4)

If it's an MY00 wouldn't it be a Phase two boxer ECU which does learn if I recall correctly?

NS04

GC8

I believe that it would; Id lost track of who started the thread by post #14 though.....

Simon

GREEN SCOOBY

GC8!

just had a quick look on the inside of the filler flap and it says

Use unleaded super gasoline only in around 4 different languages, maybe I have the PPP fitted and dont know

Scooby_Snax

Mine too - but US 'Super' Gasoline is 95RON.

GREEN SCOOBY

Mmm! then that means their petrol is even worse than ours it could well be a us sticker then! but I always thought of it as super unleaded was to be used in this country, Oh well as i said in the earlier post, you learn something new etc.

VWscooby

Always wondered about this. Everyone harps on about using SUL only but to be honest these cars are fitted with knock sensors for a reason. Yes you will lose power but it isn't QUITE as critical as everyone seems to believe.

Doesn't stop me from running on SUL with octane boost though!!

ozzy

It clearly states in the Impreza Turbo MY99/00 manual that you should use at least 95 RON fuel.

In some countries Unleaded is 90 RON and Super Unleaded is 95 RON.

In 1999 Subaru introduced the Phase 2 engine (can be found in some late '98 models) and the ECU will re-learn if reset in "safe map mode". You can force the ECU into fine-learning mode by following these instructions - http://www.stefanostadal.homedns.org...etting_the_ecu

Stefan