This is a bit like one of those "If you have to ask the price, you can't afford it!" questions. If the cost of better petrol is a consideration for you, you should probably have bought another car, as all Imprezas have a thirst, turbocharged cars especially so.

At end of day it's difficult to give ballpark annual fuel costs with these cars, as economy varies wildly according to where and how you drive. It also seems to be the case that SUL gives slightly better fuel economy, reducing the overall difference in cost.

Running on Super Unleaded is primarily a performance issue - your car will feel and drive better on the higher octane petrol. You bought a high performance car, so why skimp on what goes in the tank?

Edited to say: Is this WRX a UK spec, new age car, or a classic shape Japanese import? The above was written on the assumption you have a UK car. If not, using normal 95 RON unleaded could be very bad for the health of your engine. Super plus octane booster is necessary for these cars, unless they've been remapped for UK fuel.

[Edited by greasemonkey - 9/4/2003 4:53:16 PM]

 

Franko: If your car is intended to run on Japanese market, 100 RON fuel, you should really be running booster on top of SUL/Opti to bring it up further.

The fact that the car runs "rougher" should be enough to tell you it isn't entirely happy. If you don't have a KnockLink, you should fit one ASAP, and go back to running booster until you know the car isn't detting.

[Edited by greasemonkey - 9/4/2003 5:26:30 PM]

 

just got my first WRX, and the sales guy recommended using 98 ron (optimax type) to get the best from it. But it is a lot more than 95ron.

Anyone done the sums to see the difference in cost over a year doing say, 10k miles?

 

apparantly if you use 95 ron instead of 98, you get less MPG so the saving may not be as much as you think.

 

Not sure of the cost's over a year but putting 97 in is a lot cheaper than a new engine .

Alec

 

DONT UNDER ANY CIRCUMSTANCES PUT 95 STUFF IN - UNLESS YOU HAVE THE CAR RE-MAPPED FOR IT. DONT BE A TIGHT-WADD - PUT OPTIMAX IN. HAVE A SCOOBYECU REMAP DONE TOO (£75-90)

 

Steady on chap. For all we know the "WRX" he's referring to could be an MY01 onwards UK car. No need to go scaring the sh*t out of him unnecessarily

 

Fairy snuff

 

Completly agree with you greasemonkey...

Mines a classic import i ALWAYS use optimax... is this ok or should i be using octane boost too???

I used to uses octane booster but havnt done for a while... engine sounds slightly louder and rougher without it than it does with it..

 

its a MY03 WRX, UK one - just picked it up today

you can see pics here

http://www.scoobynet.co.uk/bbs/threa...hreadid=246898

 

Thanks for the advice greesemonkey...
I dont have a knocklink... fully deecated.. and i don't even know if its been remaped or not.. i'll go onto octane booster... have it remaped then i have peace of mind...

Thanks

p.s sorry if i hijacked the thread

 

Too many things you don't know there chap! Even with booster, the decat could still put things out of kilter so you need the KL as a matter of urgency. £130 or so is a darn sight cheaper than a new engine!

 

my first performance car... i didn't even know what optimax or ron meant at first haha

KL.. where from? how to fit HELP please?

Driving from dewsbury to birmingham this weekend... saturday there and back and then sunday there and back... kinda worried now

 

KnockLink and sensor can be bought here. You can get the Bosch knock sensors a little cheaper elsewhere if you want to shop around, but bearing in mind the extra hassle it may not be worth it for you.

Fitting is simple job of bolting sensor to block, routing wires through bulkhead and connecting to display and power source on the other side. Boost gauge and AFR meter also well worthwhile adding if you don't have them.

"Normal" motorway and town driving shouldn't cause you any undue worry, just try and avoid burying the throttle until you know what it's doing.

 

Thank you for the help Greasemonkey..

Much Apreciated