U WOT!

I've got a 94 wrx sti import which i've filled with optimax since i got it in November. I'm stuck for filling it up at the mo and was wondering if it would be safe to fill it with Tesco SUL as a one off. Just one tank while i wait to get optimax again.

beamer

Shouldn't you use octane booster as well as optimax ?

Spoon

Sul is 97ron and Optimax is 98ron so there isn't a huge difference. Your car will be mapped for 102ron though so it's your choice. Many run 98ron+booster to get as close to 102ron as possible.

Maybe put in enough Sul to reach an Optimax supplier then consider booster too.

I'm sure if you aren't hooning the car around 97ron will suffice but only that, don't expect things to not melt if you drive on wot most of the time.

Elmer Fudpucker

I'll fill my car with pond water before I use supermarket fuel

greatwhite

Errr, it the same stuff as the the big oil companys???????????

Fasterbaby

Yeah, it all comes from the same place, i live near one of the biggest refineries in the country and know a lot of their drivers, believe me there is no differance...

Nick

Yes, the fuel is exactly the same stuff. However the brand names put in various additives to clean the injectors, make it burn better etc.

greatwhite

The brand name use exactly the same additives as the supermarkets do.......

It is exactly the same stuff!!!.................far from pond water!

pslewis

My cars tell me that it is FAR from the same stuff!!

And I do what my cars tell me - they know best!

Pete

wez_sti

going back to the old booster point, my 95 Sti has been run on SUL only since import in 99 and has had no problems, vn spoke to services at power engineering and they said booster is not necercary unless driving prolonged periods like a maniac or for track days. now i'm not going against what GM and such suggest but surely they must have some clue being a spcialst performance garage??????

btw i know little about cars and i'm by no way suggesting everyone stops using booster, more a query than anything....

Chris_

When I first got my Scooby (a wrx my94 jap import) I never knew it had to run on any special fuels or boosters, so in the 5 years that I have had it, its been run on Tesco's 95 ron with no problems whatsoever.

FYI. I have just cut and pasted this from the SIDC website.

Many questions are often raised regarding the type of fuel needed for the Impreza. The sticker inside the petrol cap says use Super unleaded only, but this has different meanings in different countries. In the UK, the standard (or premium) unleaded fuel is rated at 95 RON, the same as the Super available in other countries such as Australia and the US. In the UK, Super Unleaded is rated at 97 RON (was 98 until 1999). In Japan, it is 100. Generally, in the UK, normal unleaded is fine. In countries where lower quality fuel is available, then the best advise would be to run on the Super (or Premium) Unleaded fuel. Beware of octane boosters, as many contain lead or lead-like substances which will damage the catalytic convertor and oxygen (Lambda) sensor..

From the knowledge we have so far, it seems that the Engine Management System will react to a lower quality fuel by detecting the onset of knocking. In this case, it will retard the engine timing and reduce the maximum boost available from the turbo. It will then run on these lower settings until such time that the system is reset, though the system should eventually re-adapt to the higher quality fuel. Resetting the ECU simply speeds up this process.

Some owners report gradual improvements by simply running on the higher spec fuel, but most will find that although it is not any faster: the engine will be slightly smoother and the economy increased marginally (by about 5%). This subjective improvement can be hard to justify against the premium in fuel price.

Ray_li

How much for octane booster and how much do you get?

wez_sti

can get for £4/5, soon adds up everytime you wanna fill up though. chaper than a re-build though if the stories are true. unno what to think anymore.

think its 'megabusa' that can get millers

good price, will get mine soon prob

greasemonkey

Just what exactly do you think I've said? My attitude (and that of many others) in these cases is always that you should use octane booster on an import until/unless a knock measuring device tells you you don't need to.

This is nothing more than simple good sense, and it's infinitely preferable to a knackered engine. If Power Engineering tell you you don't need it, and your engine subsequently fails as a result of damage caused by detonation, do you think they'll rebuild your engine for free?

StickyMicky

better safe then sorry

Leslie

My '94 STi has a better exhaust and up-pipe with ported manifolds and is controlled to run just under the fuel cut at about 16 psi. I use Optimax straight and never got more than two green lights on the Knocklink. I think you would be safe on a tank of Esso SUL but don't rag it too hard just in case it does detonate on it at the higher boost levels.

Les