optimax

[plug]

I have got a 2000 (w) speed six and was woundering can i use shell optimax in it, does the higher octance rating matter. Is there many advantages to using it for the engine and performance.

[RUSSELLM]

Should you be using anything other than optimax ???

[GCerbera]

First time I didn't use Optimax in the new car, it started to run rough.

Bl**dy BP, all that spin about Ultimate, nasty stuff - stick with Optimax and get
a Shell card or shares!

[beano500]

GCerbera said:

Bl**dy BP, all that spin about Ultimate, nasty stuff - stick with Optimax and get a Shell card or shares!

Even in the Griff there seemed to be a noticeable difference when I had three consecutive fill ups on the BP stuff. I'd always drive further down the road to the Shell garage if possible....

[pdavison]

Always used Optimax in my W reg Speed Six, it does run smoother.

[tannertime]

Deffo agree - was recommended Optimax by the dealer when I bought my S6 and my handbook (and a sticker in the engine bay I think) recommends 98RON. The BP Ultimate is only 97RON - the gypsies.

[kojak69]

Always Optimax.

[plug]

It says in the hand book to use 92 octane for the 4.5, speed six and 98 in the 4.2.Is this not right then?

[yiw1393]

My handbook says the opposite - 4.5 use 98 RON and 92 RON in the S6 and 4.2.

When I got my 4.5 there was fumes and nowt else in the tank so stuck a tenners worth of 95RON in. Boy did it pink! Filled up twice now with Optimax and a much happier bunny.

[yiw1393]

My handbook says the opposite - 4.5 use 98 RON and 92 RON in the S6 and 4.2.

When I got my 4.5 there was fumes and nowt else in the tank so stuck a tenners worth of 95RON in. Boy did it pink! Filled up twice now with Optimax and a much happier bunny.

[Dai Capp]

The handbook for my 4.5 says 98 ron only...

interestingly when I ran Tuscans they ran on normal unleaded as per the handbook...

Cheers

DC

[plug]

So is it ok to run a car on a higher octane rating, i did'nt think it was, only use same or lower.

>> Edited by plug on Friday 23 July 17:30

[TVR SLag's BiL]

plug said:

So is it ok to run a car on a higher octane rating, i did'nt think it was, only use same or lower. >> Edited by plug on Friday 23 July 17:30

THE SAME OR HIGHER! NEVER LOWER!

It is fine to use Optimax in all petrol road cars, even SMART's!

[plug]

TVR SLag's BiL said:

THE SAME OR HIGHER! NEVER LOWER! It is fine to use Optimax in all petrol road cars, even SMART's!

ok thanks, i just looked at the sticker next to the filler cap and it says 95 octane.I think i will start useing it the expense.

[RUSSELLM]

Have you guys with the 4.5's got a switch on the dash for different fuels or did I dream it ?

[yiw1393]

Russell, that's a Red Rose conversion that has that. Apparently it lets the engine management adjust timing to allow for the higher/lower octane. Mine's not a RR which is why it pinks like a bag of spanners on 95 RON!!

[RUSSELLM]

Aaaahhh. I saw one before I bought my car. I think it must have been on the 4.5 I test drove, seems I missed a bargain.

I'm presuming the red rose has no external markings ?

[kevin63]

I have always used Optimax in my Speed Six and have just started to use it in my smart and will not now use anything else now.

[Julian64]

Hmmm this thread again. I think the answer might be not so straightforward.

My car is a 4.5 and says 95ron on the fuel filler. I have used this from day one, and then when I saw 98 in the handbook started to use that instead. Immediately having to change back to 95 as the car was running rough on the 98!! For a while I just thought my car was opposite to everyone else and liked the cheap stuff.

However when I stated to play with the ECU I found that zeroing the adaptives cured its dislike for one fuel or another and that the car could be trained once the adaptives were reset to enjoy either.

I therefore think that the answer to this problem is that the car will eventually like whatever you run it on once it adapts. Sudden changes in fuel type are not tolerated well in either direction.

Interestingly I found my adaptives were different on the two types of fuel but not particularly closer to zero on either type.

[Tam Lin]

Julian64 said:

Immediately having to change back to 95 as the car was running rough on the 98!! For a while I just thought my car was opposite to everyone else and liked the cheap stuff.

Not sure if the AJP8's have a knock sensor: running rough is one thing, pinking enough to damadge a piston quite another, so I would have thought a higher octane diet is a GOOD THING. I think the rash of 95 Octane-only labels in the car industry was caused by panic that people would fill up with lead-substitute, and knacker their catalytic converters.

Julian, how many duty cycles does the adaptive mapping need to do its stuff? Or does it only adapt if zeroed?