stifler2k

i know super is ron 97 and opti is ron98
what i need to know is whether i will be ok using supoer unleaded as my nearest shell garage is fuking miles away, to be precise, a 30 mile round trip just to fill up!!
cheers
ben

NelsonUK

Well that depends on what sort of Scoob you have mate - Jap or UK ??

Trem

iTrader: (3)

BP do one now called Ultimate, anyone know what ron that is?

stifler2k

its uk but has a new ecu, not sure which one exactly but apparently set tp run on optimax...

Barnesy

I think you have just answered your own question.

"apparently set tp run on optimax..."

Keep putting the optimax in!

Brun

elgordano

ultimate is 97

hades

For normal UK ECU maps, some people seem to find SUL is better than optimax, others find the opposite. However, optimax is 98.6 RON IIRC, so if you have a new map designed specifically for this, and run lower rated fuel, one of two things are likely to happen:
1) The lower octane fuel causes knock, the ECU detects this and retards the timing. The car runs fine, but with reduced power.
or
2) The lower octane fuel causes knock. The ECU either doesn't detect it, or doesn't back off the timing etc enough. After a while, the engine breaks in a fairly major way.

Eric Chadwick

Buy some octane booster and use the BP ultimate. It'll work out cheaper than a 30 mile round trip to fill up.

Try sccobymania.

hades

Seems strange, but just come back from a 500 mile round trip. I set off with 1/3 tank left of optimax, filled up with ultimate, and about 100 miles ago, put in Esso SUL. For my car (a UK WRX02 with Ecutek, exhuast, i.e. set up to run on UK fuels), I think it ran worst on ultimate. If anything, it's best on SUL, but SUL vs optimax is very small difference. I think ultimate is maybe a small backwards step compared to BPs old super plus (sorry BP!)

Chaddy

For what it is worth,I think my 00MY runs slightly worse, more hesitation, particularly immediately after gear change, on Optimax, seams to run better on Texaco Super Unleaded !