300bhp/ton

What fuel should these be run on?? And is it possible to run them without an additive?

I know in Japan they have 100 RON fuel, but I hear this hasn't always been the case.

Would really like to know as its bugging me and is crucial to my next purchase.

I've been looking at Toyota GT-four's and it seems even the JDM ones are fine on just 99 octane (T99 or V-Power). Is an STI IV really going to be more expensive to run and a pain needing additives?

Also how much per tank does a descent additive cost?

Thanks.

dazdavies

iTrader: (22)

You'll be fine on vpower and T99, I wouldnt use anything else though especially BP Ultimate.

myblackwrx

iTrader: (1)

imo ANY STI should be run on 99 although i believe the V and VI were actually mapped for 100 though.
The ecu should be able to cope with the small change in RON rating.
A different problem maybe HOW each petrol gets to it's RON rating though (via additives put in by the petrol companies)

300bhp/ton

Thanks.

So does anyone know what fuel an STI III or IV was mapped for from the factory?

[-(o)-]

iTrader: (1)

My (as far as I know) unmapped V has done over 100k, at least the last 40k on 99 RON with no problems.

myblackwrx

iTrader: (1)

I'm pretty sure Premium in Japan in 97/98 was 98RON

300bhp/ton

Thanks. Its a weight off my mind. I want the car as a daily driver and don't really want to faff about with extra bottles of additives, not too mention the additional cost.

myblackwrx

iTrader: (1)

It may be worthwhile looking to get it remapped (aftermarket ecu unfortunately) for UK fuel to give more piece of mind (plus the advantage of running a bit more power and ,believe it or not better mpg)
Always worth carying some octane booster especially if you're going somewhere that may not have 99 ron fuel

V4JDMSTi

iTrader: (2)

+1.

When i got my first import (95 wrx i run it on sainsbury's sul and NF Octane Booster. Then when Tesco 99 came out junked buying the booster for everyday use.

300bhp/ton

Good idea about always carrying some octane booster. Didn't think of that but makes sense really.

Which octane booster is a worthwhile one to go for? I know some aren't worth the money and don't do much.

Also, I've heard people say of a replacement ECU, but were can you get these from and which makes??

Ta

myblackwrx

iTrader: (1)

Millers Octane Plus is nice an simple it's one bottle to one full tank of petrol (about £3-£5a bottle)
Nitrous Formula you have to measure out and is about £10-£15 a bottle i think a 300ml bottle treats upto 300 litres of fuel

There are loads of mappers avaliable this guy has a very good reputation (not saying no one else does) www.jollygreenmonster.co.uk

As you can see the remap options are not cheap.

I cheated and my V4 type R came with the Simtek ecu (SimTek Performance Engine Management) but it's worth contacting the guy at the link above to see what ecu will fit your needs

Other subaru specialists
ZEN Performance - Performance upgrade solutions for Japanese cars - Subaru & Mitsubishi Specialists
Scooby Clinic | The UK's Largest Independent Subaru Specialists | 01246 590 807 - Chesterfield S42 6QX
< < < ENGINE TUNER > > >
Welcome to the API website
AndyForrestPerformance

not everybody but just a few to look at

300bhp/ton

Thanks

V4JDMSTi

iTrader: (2)

The NF one is about the best I found. Or I used the Sikolene one. Again you have to measure it out which is a pain tbh.

Other mappers that will be able to advise you:

Mocom Racing - Performance car and trackday products
Xtreme Scoobies - Tel: 01245 363623
Roger Clark Motorsport - Home

joz8968

iTrader: (13)

I had to do take a double take! lol

Just seen your new car in your "garage" - very nice! I didn't realise you were into tail-out shenanigans?

Did you get her from Miguel at Newera at all? (A lot of their imports seem to come fitted with the aftermarket 22B-style bumper).

myblackwrx

iTrader: (1)

Well i did mention that i was upgrading
No i got it via my local garage who knew i was looking and luckily there was someone selling.
Although i do know of Miguel as my 93wrx came from him via another garage.
Thought the bumper looked different just thought it was part of the facelft DOH (it's a whole new world this later model impreza malarkey).

Not really into tail out shenanigans but i just love the 2 door look,i feel more comfortable in them and tbh oversteer is a lot easier to control than understeer imo.

I've been following you posts about gaining a whole lot of power

joz8968

iTrader: (13)

You really think oversteer is more controllable then understeer!!!

Wish I thought that.

myblackwrx

iTrader: (1)

i may be wrong tbh ,a little driver school education may be in order

joz8968

iTrader: (13)

If you do find oversteer easy/enjoyable, you should do some kind of club level racing. Hillclimbing would be ideal...

joz8968

iTrader: (13)

Bloody Shell garage still shut in Groby Road, Leic. so was 'forced' to get BP Ultimate 97 (for fear of running out ) at next garage along.

Flipping heck!... Apexi PFC's knock CEL flickering away like the proverbial Xmas tree lights, when laying waste to a Golf GTI Mk.V, and then subsequently a new shape Renaultsport Megane lol.

So, yet another EJ20 engine that hates the dastardly BP Ultimate!!! Curses! lol

myblackwrx

iTrader: (1)

Cannot understand why BP Ultimate (slightly ironic name methinks) and imprezas don't get on?
I'm off to Egham at the end of the month and they have 1 of the garages that sells their 102 RON fuel ,you need to ask the cashier for the key to unlock the pump

Apologies to the OP for going slightly off topic.

joz8968

iTrader: (13)

Christ, that must be one of only a handful of 102 RON BP outlets in the country! Is it very near you, then?

lol at the key for the pump! Mind it is about £2.40 per litre, isn't it?!!!

myblackwrx

iTrader: (1)

no my mate lives up there.
Don't know the price but i'm sure as hell aren't paying whatever they want for it

joz8968

iTrader: (13)

What, are you just going there to... er, look at the pump, then?!

myblackwrx

iTrader: (1)

Funnily enough no it's on the way from my mates house to Egham and Staines.