Guys i understand many of you run Optimax 98ron in your cars. My local sainsbury's sells super unleaded. Apart from being 97 ron, is there really that much difference?

 

Optimax is by no means essential, if you have a UK car it will quite happily run on normal unleaded. However most people don't and opt for the extra 2 octanes in SUL.
To be honest I cannot tell any difference what so ever when I occasionaly use Optimax. I reckon it's a big marketing ploy by Shell to brainwash people into thinking their car will be faster if they use the stuff.
So in a nutshell, stick to SUL and you'll be fine.

 

THANKS M8

 

Im not using SUL, not when its between 5-10p a litre dearer than Optimax

 

If you only put in the odd tank of Optimax etc your engine management won't have time to adjust fully? Just a thought.

 

Depends on your model scoob the newer the scoob the faster they adapt.

 

ive always used optimax in my s2 for ages

but there has been so many posts regarding sul being better

 

Main reason to use Optimax is to prevent det especially on Japanese imports which are mapped for 100-102 octane.

 

I too generally find Optimax is a fair bit cheaper than SUL, and it's much easier to get than it used to be - even the small Shell stations around me seem to be getting it.

Regarding using normal unleaded though - the label on the filler flap of my MY01 WRX says only use SUL?

Deano

 

u need to be running it for a good few fill ups before u will notice a diff.
or perform an ecu reset.

I find i get better over performance and mpg from optimax than any other.

 

People on this net who have a lot of experience have said that Esso SUL gives the smoothest running but Optimax gives best protection against detonation. It you don't have a Knocklink you wont know about detonation until your engine runs a big end, melts a piston, or throws a rod. Just one RON point can make an enormous difference as far as anti-det is concerned. Supermarket petrol should never be trusted to be top quality, it is known for having a shortage of the good additives.

You might think its better to spend a bit more on petrol and save an immense repair bill for your engine.

Les

 

Optimax certainly gives better protection against detonation. I get more lights on my knocklink without Optimax

 

iam about totake delivery of an import MY95/96 WRX what would be the best fuel to use? and is this very important like if ijsut put normal unleaeded in it, it will cause some damage?

cheers fellas!

 

Personally I would get any Jap import re-mapped for 97SUL and not take the chance of maybe maybe not finding a Shell station and not having a continuous supply of octane booster.
Just my opinion...

 

You will be pushing your luck to use normal UL fuel Mickey, the money saved wont pay for the eventual rebuild. At least put SUL in it or consider Optimax.

Les

 

Turbo_Steve can you say whether you get similar results (fewer lights on the knocklink)with Esso SUL?

 

what is Octane booster, where can you get it and do you put in with your petrol and is it expensive?

 

Mickey,
Have a read of the FAQ http://www.sidc.co.uk/faq.htm it pretty much covers most things.

 

cheers for that link mate but it still leaves loads of gaps like at the start of the thread it says not to really use octane boosters, then later on says that you should use em on track days

well i think i will use either optimax or super unleaded for my import MY95 - any good?

is "premium unleaded) just normal unleaded like what you would put in a micra / vectra?

cheers for any info!

 

I presume worries about detonation apply mainly to imports rather than standard uk models (mines an STI7)???

 

Er Wideboy....... No

UK ones go bang too

And it ain't cheap.....

PS When mine went pop it was almost standard as well

Even for standard UK car.... a boost gauge and knocklink are recommended by those in the know. I followed John Bank's advice to try and save me another £3,567.85

 

Mickey I'd definately use Optimax, I used unleaded in my 1999 WRX import and melted 2 engines (the 2nd only did 40 miles....NUL was still in tank after re-fit )
THEN I was told to use optimax.
It may be a few pence more but it will save you £1000's

 

I've always used Optimax, MY00 and MY03 PPP, good MPG and smooth running. Tried SUL on a number of accassions, but noticed no performance difference and it was more expensive.

Dan