Ok, I have had a look and search through the forum about what is the better (not Best) fuel to use in a MY99. And there are some pretty mixed views. Some people say "DONT" use Optimax, where as most people I know run Optimax, is this a biased view, or just that those people must have had a bad experience?

I have always run on Optimax, but after a recent move (Home) I now live between 2 BP garages, so have been putting BP Ultimate in.

Also after reading about Reseting ECU's, its it wise to mix Optimax and BP Ultimate, or should you stick to 1 fuel type?

And lastly, what is the better fuel to use in a Impreza Turbo 99 (UK)? I never knew Tesco's did a super, is that any good?

Thanks for your time.

Paul.

 

I use optimax and Tesco 99. Both good fuels, but obviously with optimax you get the added benifit of the engine detergants.

 

Optimax! NOT BP ultimate.

Who on earth told you not to use Optimax???

NS04

 

Tesco 99 in MY00 UK Turbo.

I found BP Ultimate expensive, and the car didnt seem to run as well as it does on Tesco 99 - could have been a bad couple of tanks, could have been my perception. But since I have started using Tesco 99 I see no reason to go back to BP Ultimate.

I try and not mix fuels in the tank.

 

Most mappers seem to be of the opinion that running the car on coal would be preferable to BP ultimate ; scoobies do not seem to like it at all - frequent reports of increased det with BP and subjective reports of owners suggest the cars does not "feel" happy on BP.

Optimax seems to be the most highly regarded for Scoobies, but Tesco 99 is also getting good reviews.

IIRC MY99s periodically try and advance ignition to account for improved fuel quality, but take longer to adapt than new age cars. It will also most likely take more than one tankful of a fuel to start appreciating the benefits.

Ns04

 

I only use Optimax in my classic sub, a mapper near me said he would not take my car out hooked up to his laptop unless it was running on Optimax.

 

New_scooby_04, I read it on a post on here I think.

So Optimax is probably the better between BP, and Tesco 99. Purely for having the engine detergants?

 

Well, to the best of my knowledge telling someone they shouldn't run a scooby on optimax is bollox!!

I wouldn't use BP ultimate, nothing to do with detergents; scoobies don't seem to run as well on it if most owners reports are to be believed. More tellingly, if you speak to engine mappers, they don't like it all generally, cars start to DET on it a lot sooner than other SULs by all accounts. People who have scoobies with knocklinks also report more activity on BP ultimate than other SULs.

Optimax is 1RON down on Tesco's 99, but has proven detergents that help keep the internals clean and many peole (including me) report that their cars are very happy on it. It would be my choice. Tesco 99 is also highly regarded and Esso SUl also seems well liked.

My MY99 was recently mapped for Optimax and acheived 319bhp on a day with 30 degree ambient temp, no DET whatsoever! I've never had any KL activity on it, even when I was driving the car prior to being mapped on a hot evening, with a sports cat exhaust, ported headers and new turbo!

I use Optimax every time!

Ns04

 

They all have detergent packages. Ultimate and Optimax make a big thing about it as part of their marketing strategy. It's all down to which feels best in YOUR car.
JohnD

 

Tesco's unleaded. It works fine for me so why pay more?
dave

 

oh god! here we go again!

 

Agreed, the website from the people who supply Tesco with their '99' clearly states that additives are put in the petrol to clean the engine, etc. Whether those additives are as good as those in Optimax is another matter and not something we can objectively know the answer to ......

 

Base stock of optimax is a different blend and it only comes from optimax silos.
To my knowledge all the other fuels are just NUL plus additive package mixed in at refinery before being tankered off.

 

All the way for me!!!
Its all the same petrol as there is only a small number of refineries in the UK. Which all the major brand leaders buy from certain refineries depending on where you are in the country. So for example, Tescos in Nottingham may buy the same fuel as say Shell in Derby. It all depends on the additives and detergents which are added aftermarket which makes the difference in performance.
Just to confuse things further, sorry. But you may have been going to Tescos or another garage to fill up with your chosen fuel and the car runs like sh!te. Thats because the buyers are always on the lookout for cheaper fuel to sell and also it may not be the same batch. (flamesuit on!)

 

Optimax always comes out best when I map, its 98.6 minimum, but its not just about the ron value, Tesco 99 always seems to be as good but to me there are differences, I don't have any qualms about telling people they can use either if Optimax mapped. My experience .... Essso 97 next up with Total Exelium (spelling), avoid Texaco 97 and BP Ultimate, both induce det.

Bear in mind I am talking about remapped engines here where things are custom mapped to start with, Ultimate tends to knock ignition back which can make things "feel" different, not helping performance though.

based on my experience when mapping.

cheers

bob

 

That's true for all the fuels except the Tesco 99, which is an entirely different formulation due to the bio-ethanol. This has been covered at length, and repeatedly...

The ethanol is a pretty good engine cleaner by the way - in the US there are lots of cases where the introduction of ethanol to the fuel causes poor running when the 'varnish' coating the various fuel system components is dissolved by the ethanol all at once. This can overload the fuel filtration. Once the 'varnish' is all out of the system the fuel lines and other components are likely to be squeaky-clean with an ethanol blend like the Tesco one.