16vmarc

Am i right in thinking that 40ltr of Optimax + 1 bottle of Millers will give 101ron which is pretty near to Jap fuels 102ron.

Mixing 95ron with 2 bottles will make the mixture too rich wont it?

I have no intention of doing the latter by the way!

16vmarc

Anyone?

blot

20 litres optimax + millers CVL gives 101-102 ish allegedly, also gives rather spiffing flames

andyr

I think that there's a limit on how high the octane can be raised by OB so adding much more than the recommended amount might make very little difference to the octane level.

RS Grant

But running OB in a UK Impreza is a BAD thing isnt it??

A friend wanted to do this when he had the car on rollers as he was convinced it would give more BHP, I told him not to as I was sure I'd read on here somewhere that you shouldnt run a UK Engine on Optimax and OB. Is that right??


Cheers,
Grant

jjones

detrimental effect on spark plugs?

alanbell

iTrader: (6)

Mines a uk, running near to 400bhp , mapped by andt f, I use ob , N/F one bottle will do 5 tanks, cheers,

16vmarc

Incase anyone is interested, the car in question is a JDM spec Celica ST205 GTFour

jonny gav

iTrader: (1)

optimax should be enough but the cars original map is for 100ron fuel, to be honest millers only lifts the octane by 2 ron points.

there are 10 ron points in 1 ron.

TonyBurns

iTrader: (3)

Millers will increase by upto 2 ron (so running from 98 ron fuel you can get upto 100 ron from it).
It does no harm to my MY03 JDM STi, if anything i see some noise just running optimax, though nothing too serious, with the millers i dont go above the 2nd green

Tony

PS, i bottle of millers octane plus to every 50ltrs of fuel.

RS Grant

Check on the GT4OC.... But I'm sure that the ST205 can run normal Optimax.

IIRC then you fill the tank, take out the ECU fuse.. and then re-fit it.

My friend runs his this way after someone from the Owners Club telling him it would be fine, and he has had no problems at all.


Cheers,
Grant

andyr

I think that WRXs requirements for OB is down to the fact that the ECU in it (certainly in a classic WRX) is not capable of retarding ignition sufficiently when the engine is running UK fuel which is far more prone to det that home market (102 ) fuel ? If our fuel was closer to the Jap stuff then it would be ok but 95 ron or whatever it is we get is poorer by too much than Jap stuff for the ECU to be able to make sufficient change and hence the big risk of det unless we use Optimax + OB ?

jonny gav

iTrader: (1)

right on Andy, a lot of octane boosters are a rip off too, the best VFM OB i have found is NF.
it is messy to use but does work.

millers works too but £ for £ is alot more expensive to use due to the amount you need the get the octane up to the same level.

stay away from pro boost as its a waist of money

all in my opinion.