View Poll Results: What fuel (UK UNMODIFIED cars only)
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What fuel do you use (UK spec cars only)
#4
Originally Posted by MattW
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.
#7
Originally Posted by ru'
Filler cap sticker says 98 ron minimum, and that was pre-ppp.
Optimax all the way.
Oh, and best get the flack jacket on...
Optimax all the way.
Oh, and best get the flack jacket on...
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
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#8
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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. ).
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. ).
Last edited by ALi-B; 24 January 2006 at 01:47 PM.
#10
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
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
#11
Scooby Regular
iTrader: (5)
Originally Posted by scooby546
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
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
Nick
#12
Moderator
iTrader: (1)
Originally Posted by Gary C
Would it be worse to continually switch from 98 to 95 and back than to run on 95 ?
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 ? )
#15
Scooby Regular
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
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
Last edited by EddScott; 24 January 2006 at 04:22 PM.
#19
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 !
Come on Mr Lewis, give us the definative answer !
#21
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Originally Posted by Gary C
...
Round here the diff between Optimax and 95 is 17p/litre
Round here the diff between Optimax and 95 is 17p/litre
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
Last edited by Raartoot; 24 January 2006 at 06:06 PM.
#23
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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!!!
#24
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!!!!!
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!!!!!