gubby

I have a 55 WRX Wagon.

I have been advised by the Subaru specialist that looks after my car that it is unnescessary to use fuels like Optimax and that using Premium unleaded is fine.

Which is obviously good considering the price of fuel. But, does Optimax have any other advantages to offset its higher price. i.e. does it give the car a better performance or economy?

Bubba po

I don't think the increase in economy is sufficient to completely offset the extra cost. You might get a bit closer with Sainsbury's unleaded as it's about 5p/litre cheaper. Optimax claims to have additives that clean and protect the engine, but I'm getting a bit sceptical myself.

Scooby.Newbie

Otimax being 98 ron is meant to be better on performance because of the compression before ignition rating but im not sure that it actually improves the economy of the vehical, my closest Shell garage is 15 miles away and although it seems to pull a little better when ive been there ive not notice more mpg, but if im driving it harder that is no real suprise, my local garage does a 97 ron and im happy to use that, although when passing will use Optimax where possible, maybe just a subliminal thing i dont know.

COLZO

EVO magazine and 5TH GEAR done tests a while back on different grades of fuel and both agreed that high performance cars ie Subarus ran better on Optimax etc. As for better economy and a cleaner engine, you will have to take Shells etc word for that. I personally use Optimax in my STI PPP as advised by the dealer, but economy...........

bigman

I dont notice any diference in using Sainsburys Super Unleaded or Optimax.
My car is a 2004 WRX, I now use Sainsburys Super all the time because it is much cheaper than optimax.

The filler cap does say min 98 ron on it; however I dont notice any diference if I use 97 ron. As for normal unleaded 95ron, the car runs like crap on it.

I get better economy on super over normal unleaded as well

swifty.....!

iTrader: (4)

i was told by my subaru dealers to just use unleaded on my 05 sti ppp as they said it would run fine which i ignored and use super or ultimate i found it does make car more responsive but thats about it.

your best just to try it and see what you think as i tried shell and i thought it was rubbish run better on normal unleaded i think sainsbury's super is very good for the price also bp ultimate is good but a bit more expensive not tried tesco 99 yet but a friend has and he thinks its as good as bp etc.

not sure if this is right but i'm sure i read it somewhere that sainsbury's etc buy there fuel off bp so it arrives in sainsbury's tankers but it really bp ultimate but can't remember where read it so for a penny or 2 more than normal unleaded you can't go wrong. as anyone on here read same thing as me or am i losing it?

timuk1

I have run sainsbury's super unleaded (ron97) in my my04 and it runs fine, i have also tried the tesco's (ron99) and made my engine feel lumpy, I think that shells (ron98) works the best in my car give it a nice smooth exceleration.

Jamesemt

I use BP Ultimate as its the only local decent fuel - the car runs fine, but I don't like the way the tickover drops right off, like its almost going to stall, before rising again. It only happens when I freewheel to a stop, like pulling up to traffic lights in neutral...

Shell seems better in this respect, but none local to me

Stainy

Just made sure mine had been running on Sainsbury's for a while when I had it remapped. It's now mapped for the stuff I put in

I don't notice a difference if I put Optimax in tbh.

comic cuts

I'm on my 5th tank of Optimax now and have noticed a power increase, I need to lift off the accelerator (honestly!) more than I did, and am using less fuel than with 95 RON.

CC

bluto22b

Tesco's finest 99RON SUL. 97.9p/litre. Good for Scooby, Good for Blutes

AlloyUK

Is it an import ? My 94 WRX Wagon has the 98RON chip and I only use Shell OPtimax, oh unless I'm on the LPG Shell Optimax for me.

bluto22b

Everyone who uses this sh1te only does so because they have been brainwashed by other numpties on this forum who will pay over the odds for a placebo I have seen little or no gain over supermarket SUL

AlloyUK

I don't know about others my friend, but I've had the car much longer than I've been on these forums. I've have used reviews from so called independant sources.

Fancy calling them Numpties..

bluto22b

This was not a generalised statment aimed at everyone on this BBS but the **** anoraks who think they can notice the difference in performance when changing from Mobil 1 5w/40 to shell helix 5w/40 The same applies to fuel

rossi_classicwrx

I use optimax and octane boosters on mine but its a jap import. This may not be fully needed but it gives me piece of mind that i have got the best fuel in there that i can. I'm not sure if the lower ron fuels can cause damage to engines but after i recently have had to rebuild a new engine and seeing how much it costs, im definatly not taking any risks!!

gubby

OK, so it would seem that unless you drive a STi with PPP or a Jap import, you may be just wasting your money paying the significant premium on 95 RON fuel if you just drive a cooking WRX.

Awd Chaddy

Wow! Not so quick cowboy!

I drive an 03 WRX which until recently only received unleaded petrol as per the manual instructions. However, I decided to use SUL when my local Tesco's brought 99RON petrol to York. I immediately achieved a 2-3mpg improvement in performance (not sure if this outweighs the price premium?) but also felt the car accelerate more freely (Which is definitely worth the extra cost!) Then a month ago I tried Shell Optimax and still maintained the fuel efficiency but the car did feel smoother under acceleration.

Not a scientific test but it does seem to show a real advantage for using SUL.

New_scooby_04

iTrader: (4)

Bubba,

I think Evo did a test on this not too long after Optimax was released. They went as far as stripping engines down to examine this property of Optimax relative to several SULs etc... IIRC this supported the claims made by Shell. I also think that in the recent test to determine how well performance cars ran on supermarket SUL, Optimax etc, they pointed out right from the start that Optimax was proven to "clean" your engine.

Mine seems very happy on Optimax - It's smooth, punchy has a decent top end and I never see any more than one flashing green on the K(c)ocklink. I'll continue to use it.

To the poster: No, you don't need to use Optimax; SUL would be fine, but many owners report their cars running the best on Optimax.

Ns04

New_scooby_04

iTrader: (4)

Any car with active knock control will benefit from higher RON petrol.

The UK WRX will run ok on regular, but will run better on super.

You get out what you put in basically.

Ns04

speedking

Don't forget that Pluspoints reduce the real cost of Optimax by 1-2p per litre depending on how many miles you do

Abdabz

I use tesco 99 - tis spiffing and i get free stuff 4 schools voucher thingies, clubcard points and ad-hoc shopping produce when required
Every little helps

gubby

Posted by New_Scooby_04Thanks m8.

Concise and to the point

Now the next question is can you fill up with Regular 95 RON one time and switch to Optimax next time and back again and so on, or does the engine not like this?

New_scooby_04

iTrader: (4)

You're welcome

New age WRXs have ECUs that adapt very quickly mate, so you can, but I'd run on min 97RON all the time TBH.

Unless you run the tank completely dry (which you shouldn't), the remains of the previous tank will "contaminate" for want of a better word the RON of the current tank; it'll take a couple of full tanks to get the fuel fully up or down to the RON you're purchasing.

Ns04