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Octane

Discussion in 'A3/S3 Forum (8L Chassis)' started by Alais DJA, Mar 10, 2012.

  1. Alais DJA

    Alais DJA Member

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    I've been running 99 Momentum in the Audi since i owned it....

    The only real options you have are:

    97 = BP Ultimate

    98 = Shell V-Power

    99 = Momentum

    Thing is, Tesco in all their wisdom have extremely dodgy pumps. I wont go into how i "proved it " to them....but i decided to put 1/2 tank of Ultimate...

    The car genuinly feels more powerful, and i rang previous owner ( as we still speak ) and he said he only ever put BP ultimate in it.....

    Is it possible that a car can remember?
     
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  3. S3featesV9

    S3featesV9 Active Member

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    No I doubt it. How can a car remember what fuel it's been using?
     
  4. Pedrosousa

    Pedrosousa Member

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    Knock control could have some kind of adaptive values....
     
  5. TDIQ

    TDIQ 8L > 8P > 8V

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    Why not? They're meant to be tested on a yearly basis so I doubt they're "dodgy"
     
  6. Gops

    Gops 6th gear @7000rpm
    Gold Supporter Audi S3

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    Shell V power is 99 isnt it? I think optimax was 98 until they changed it. But i use V-power and when its not available i use tesco 99. Never use BP, car hates it for some reason.
     
  7. Jimgrim77

    Jimgrim77 Member

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    Shell v-power everytime for me.
     
  8. <tuffty/>

    <tuffty/> Badger 5 Edition...Its all about the flow...
    Staff Member Moderator Audi S3

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    The ECU doen't remember it adapts... higher octane means less chance of detonation and less timing pull so the car will feel quicker..

    Shell V POwer is 99 octane, Tesco Momentum seems to contain something that leaves deposits on the plugs... I ran it for a while as its the only garage on the way to work when I use the S3 but after seeing all that **** on my plugs I am back on the V Power

    <tuffty/>
     
  9. Jimgrim77

    Jimgrim77 Member

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    Music to my ears that!
     
  10. SteveSAS

    SteveSAS Member

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    Mine is standard & I use Sainsburys Super which is 97 because its cheapest :thumbsup:
     
  11. Jimgrim77

    Jimgrim77 Member

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    You should only ever use the best fuel in these cars. Hiding to nothing if you don't.

    You don't see athletes eating fatty foods.
     
  12. vfr800

    vfr800 Active Member

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    I had a '95 1.8 A4 which loved Optimax - I could really notice the difference, my old A3 1.8T loved Optimax - but I had to rag it to notice the difference. My brand spanky new-old S3 - dunno yet I've only had it for a few weeks.

    Personally I like Optimax (V-Power). A few tanks fulls through the engine and my cars have always seemed to run better.

    My VFR800 VTEC will drink anything I put in the tank - but it's a Honda so will probably run on perfectly on any old cheap cr*p. =)

    Liam
     
  13. SteveSAS

    SteveSAS Member

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    Sainsbury Super is 97 and cheapest
     
  14. Paradox1

    Paradox1 Active Member

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    I use sainsburys aswell, its just gone up to 1.37 and v power is 1.44. Tbh my car don't like v power for some reason but runs perfect on Sainsburys
     
  15. rhubarb4

    rhubarb4 Certified Jardo Slayer

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    Iv been running Tesco Momentum for a year or so now Paul not had any problems, actually seemed to run better than on V power not noticed any deposits either, do you definitely think its down to the fuel.

    Chris.
     
  16. damo.h

    damo.h DVLA Say it's Black

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    Another here for the V power club. Car feels to put the power down so much better. Can instantly tell when the wife fills up. As she will throw anything in :banghead:
     
  17. Gops

    Gops 6th gear @7000rpm
    Gold Supporter Audi S3

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    Ban her! Or train her! You cannot allow this to happen. Next thing you know it'll have diesel in the tank and a "oops I picked the wrong one up"
     
  18. damo.h

    damo.h DVLA Say it's Black

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    oh mate believe me I try, and only I usually fill the car up nowadays... Cant teach an old dog new tricks as the saying goes ;)
     
  19. RyanS3TT

    RyanS3TT Member

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    I use tesco momentum in mine, as I seem to always get 5p-15p off per litre from a friend :)...

    Spark plugs get changed every 5k anyway as im a service freak.

    As for fuelling.. Probally a question for Paul.. If driving Sensibly (as I do on the work run) Rarely over 3k using cruise control (Currently getting 37mpg)...

    Is Cheaper fuel an option? - or to stick with the higher octane stuff.

    All about cost saving me.. typical in my job.
     
  20. Reload

    Reload Bird is the Word!

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    Not just cost saving mate, your car would definitely not be running to it's full potential on 95 so why use it? (Not sure if my mpg is any better on the good stuff though)
     
  21. Alais DJA

    Alais DJA Member

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    It's the CLASSIC scenario.

    Why even consider using cheap fuel to to save 50p!

    I had to be "moved on" by security at Tesco at christmas because a complete moron, was filling up his R8, with 95!!!!!

    If you cant run em properly, just sell it and get a Corsa
     
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  23. Welly

    Welly VX220 SC Driver :)

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    Same here, Momentum whereever possible and no plug issues here. There was a spate of Tesco 99 having too much silica in it, which shagged some peopel's lambda sensors - maybe remnants of that?

    Why? It's hardly like running 95 RON is going to damage the engine to be fair. The engine will just adapt to what fuel it uses so that seems a bit daft IMO.

    How do you know he wasn't going to get home and bung an Octane booster in the tank to take it up to 100 RON.

    Or maybe he ran WMI and had 110+ octane? lol
     
  24. Alais DJA

    Alais DJA Member

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    So...

    Engines do adapt and remember the fuel they use?
     
  25. <tuffty/>

    <tuffty/> Badger 5 Edition...Its all about the flow...
    Staff Member Moderator Audi S3

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    The ECU adapts/reacts to the situations that the lower octane fuel bring up... lower octane fuel will increase the potential for timing pull so the ECU will detect this and pull timing as it occurs... std maps are tuned to fall somewhere inbetween so that if used on high octane fuel then timing will normally be pulled only on extreme circumstances but allow the use of lower octane fuel as it is within the range of the ECU ability to pull timing...

    Once mapped however the maps are designed for power and therefore higher octane fuel... running lower octane fuel on a remap will normally pull more timing than std and will be more noticeable as a performance drop when compared to the std map...

    The ECU remembers fuel adaptions to compensate for air leaks etc...

    <tuffty/>
     
  26. Welly

    Welly VX220 SC Driver :)

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    They don't remember. They adapt. Different things.

    If someone cut off one of your legs, you would adapt to using just 1. That's different to remembering.

    Changes in knock readings from the cylinders define how much timing is added or taken away. Less knock and more timing will be added, giving you additional power.

    The higher the octane, the better and cleaner the burn from the fuel. The better and more efficient the ECU will see this from the reduced CFs from the knock sensors, and will slap a bit more timing in. Lower octane fuel will produce the reverse effect.
     
  27. Reload

    Reload Bird is the Word!

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    Yes, after a couple of tanks the ecu will adapt the knock sensor to take advantage of the higher octane fuel. A couple of tanks of 95 and it will adapt back to that, with potentially, depending on the engine, a loss of power. It would not, however, 'remember' in the sense you mean, it will merely adapt as necessary
     
  28. Welly

    Welly VX220 SC Driver :)

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    Which tends to be more of a hindrance than a help! lol
     
  29. Reload

    Reload Bird is the Word!

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    Beaten to it by welly. In my defence I am in Kenya atm :rolleyes:
     
  30. Welly

    Welly VX220 SC Driver :)

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    And as such, reload is a very apt name.... lol. :thumbsup:
     
  31. Alais DJA

    Alais DJA Member

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    very good
     

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