Just wondered if anyone uses 95 in their UK car as the manual says it can.

Filler cap sticker says 98 ron minimum, and that was pre-ppp.

Optimax all the way.

Oh, and best get the flack jacket on...

97 Ron Sainsburys as it says on the PPP certificate. Only 2p more expensive than 95. Will use 95 if I can't get anything else.

Same here........

Red Diesel if my mate can get it....

Homebrew self mixed.
I noticed the other day that optipiss has a BS mark now

Got my head down, but, the manual with the car states specifically that a UK Impreza can run on 95 ron.

I queried the fact that the cap states 98 and the manual states 95 with the dealer and Subaru when I bought the car and they confirmed that the car can run on 95 without any risk to the engine, but with some loss of performance.

Round here the diff between Optimax and 95 is 17p/litre

95 is fine, if it says you can use it in the manual, and you have no mods. And you don't notice any difference in performance or fuel economy, then why bother?

Especially on the daily hack to work, where you can't take advantage of the 5-10 extra horses

As a from a det point view for fuel types. The ECU retards slightly at high boost and rpm to prevent it, and creates a solid, reilable averaged map (unless you keep restting the ECU forcing or a sensor fault) At low/medium rpm and off boost, there isn't "that" much difference. A higher octane will result in a more advanced ignition...so is equally as likely to det on boost/high rpm if there is a problem (sensor fault, poor fuel etc. ).

Would it be worse to continually switch from 98 to 95 and back than to run on 95 ?

Probably not Gary, as I think the ECU will be able to compensate, and will over time generate an 'average' map unless / until its reset.

AFAIK it works like this - if you reset it and run on 98 for a few tanks it will go fine. If you then put in a tankfull of 95 it will re-learn its mappings as it listens to the knock sensor input. Then if you burn all of that tankful and fill up again with 98 it should re-map for the higher octane fuel - but it will take into account the lower average ron value of the fuel it has had since it was reset... resulting in a slightly different mapping than the first case.

I think thats how it works, but if I am talking sh!te feel free to let me know

Aren't some of the older ecu's better at retarding than advancing the ignition? So an ecu reset would be necessary after going from Optimax to say 95 ron and then back to Optimax?
Nick

In my opinion, yes - in some circumstances.

If the owner keep resetting the ECU to make use of the "difference" in fuels (especially on old classics - as it creates an "average" map which is more accurate and safe long term, resetting removes that safety margin)

(do dealers still reset ECUs after services - may explain the blow ups within 500miles ? )

Just use the good stuff- Optimax!

Ns04

Tesco or Sainsbury 97 Ron.

Only Optimax or at a push Tesco SUL and a bottle of booster. My car is a little modded but it had Optimax before and always will unless it runs out or Tesco bring 99 to Wales.

When the weather gets better and its time to cut the grass again, I'll be using Optimax in my lawnmower. It makes lots of pops and bangs when using SUL so with the addition of Optimax it should make grass cutting a breeze.

Still haven't worked out where to put the dump valve though

Optitax all the way, nice drive to the filling station and back

Meths!

Mine is mapped for 95 but I won't use anything other than optimax. I used super once but didn't give it death 'til I'd got rid of it.

Did not know about the averaging fuel maps. So that means it becomes a more conservative map the more you use 95 (is that true on a 53 plate STi type UK ?).

Come on Mr Lewis, give us the definative answer !

Optimax 99% of the time and only stick in a small amount of anything else until I can get to another Shell garage if caught short. I find the car runs better.

Goddddddd Dammmmmnnnnnn, thats harsh.
I use tesco 97, cant tell a diff in performance with my99(with Re-map), but can tell a massive diff with consumption, Tesco 97 gives me 110mls - 115mls to £20, where as Optimax gives me 85mls ....try it if you havnt already

Have used 95 for the last year.

Nowt wrong with it.

Guess my engine isn't made of chocolate after all!

Ted.

I am surprised to see that as many as 15% of us (not me I might add) use 95 RON. I would have expected far less. I wonder if these guys use chip pan oil in their engines!!!

I ran a uk classic for 5 yrs on 95 ron fuel and a new age for the last 2 on 95 too. no problems at all and no noticeable difference in performance or economy with either... you pays your money...

also run on chip pan oil !!! only joking

spoken to several dealers who only ever put 95 ron in there demo and new cars

maybe with ppp or modded I would run on 98 but standard!!!!!

Optimax ££££ all the way.
Luckily i'm only 1/3 of a mile from a Shell petrol station.
So i don't wste half of it just getting home.
Lexx.

Optimax 99% of the time

optimax only nothing else

Optimax only

Especially for the red ones; they're much faster so deserve better fuel!

Optimax for me, Im collecting points