Fuel Thread

Discussion in 'Engine, Transmission and Drivetrain' started by __ET__, Nov 27, 2007.

  1. __ET__

    __ET__ Guest

    As Japan have way better fuel than us I'm guessing these car are setup for the high octane rating.
    Japan is like 100 RON with there octane rating or maybe higher even?

    I am told lots of car can tell and adjust to what type of fuel we are running,
    If we use crap fuel, the car may detune itself so you would need to run
    a few tanks of good fuel so it can tell it's good fuel and then run at peak performance.

    Which brings me to the point of octane booster and AVgas.

    I have used a good octane boost in a turbo before and it does make a difference
    I found it had smoother power and maybe a bit more or was it in my head? Yea smoother power for sure.

    AVgas uses small amounts of lead has a much higher octane level and burns slower.
    A guy at work used it in one of his cars for a full 100,000 km's and had no problems.

    Anyone know if there are any side effects if let's say for example only I was
    to use a few tank fills of avgas in the Legnum? Its agaist the law so lets say for an example only.

    Also I have been told BP is better than shell has shell have additvies to make the higher octain ratings
    while BP is refined at a higher octane level.
     
  2. bradc

    bradc 1 AYC Bar

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    avgas will screw up the oxygen sensor and cause all sorts of problems. Best if you don't use it :)

    As for the octane, 98 will be fine.
     
  3. Connor

    Connor Guest

    A lot of what I have is hearsay.

    I have heard you need a cooler spark plug to run avgas because it burns a lot hotter. Having lead in it will kill your oxygen sensor, and I can't imagine it'd be good for a catalytic converter either.

    In terms of brands, I know rotary buffs used to love Shell but now don't like it. Something about a washing agent they use was fouling up plugs or something, my memory escapes me. At the time BP was the bees kneees, but since then Shell brought out V-Power Racing which may be a step up.

    For me I get BP when I can or hit up Mobil 8000 Synergy (or whatever it is). I know there were lots of independant tests done (no link sorry) and I think these scored fairly well.

    I also heard in Japan they only sell 95 and 100 octane fuel? In the US they sell 85, 90 and 96 or something? I can't remember, all too long ago and I was probably under the influence...
     
  4. __ET__

    __ET__ Guest

    Has anyone put octane booster in there VR4 yet???
     
  5. mitchy

    mitchy Leaving Skid Marks

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    nope, the only reason i'd use it was if i couldnt get 95 RON+

    octane booster fouls spark plugs, is expensive, and there is no need for it if you are using 98 RON.
     
  6. bradc

    bradc 1 AYC Bar

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    USA uses MON and not RON which is what everyone else uses. Their 91 is about the same as normal 96-98 RON.
     
  7. joe

    joe Guest

    i have put the shell vpower racing 100octain and some octain booster i will have to say it gave it a little more go, it was probably more smoother power delivery and with that just feels like more power.. i have used the 100octain a few times in the legnum and in my forester and i think its a noticeable difference..
     
  8. SiliconAngel

    SiliconAngel 1 AYC Bar

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    If you're not getting knock with 98, using 100 shouldn't make ANY difference... Get a mate to fill your car a few times without telling you what fuel they used (as long as its AT LEAST 98 RON!!) and see if you can tell the difference... and I don't mean guessing, if there really IS a difference you should be able to tell accurately.

    If there IS a difference then you're getting preignition, which isn't good... In fact its Quite Bad. In such a case if it were my car I'd be trying to find the cause - either you have 'hot spots' in your combustion chamber(s) somewhere or your air/fuel mixture / timing is out somewhere... Just sticking 100 octane fuel in to mask the problem won't solve anything, it will just delay the inevitable.

    ...

    "Hear that, Mr Anderson? That is the sound of inevitability..."
     
  9. Peter_D

    Peter_D Leaving Skid Marks

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    Not withstanding the above, if you drive with about the same amount of pressure on the "GO" button you should get more K's from a tank of 100.
     
  10. mallen

    mallen Leaving Skid Marks

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    I want 100RON - Adelaide Sucks!
     
  11. SiliconAngel

    SiliconAngel 1 AYC Bar

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    Be happy you don't, Matt - it will only make you want to retune for 100 RON, in which case you won't be able to run anything else without knock. Unless it becomes ubiquitous or you happen to live really close to a servo that does it I think you're better off without it. 98 is fine, really :)

    *someone get that guy a blanket, FAST!*
     
  12. mitchy

    mitchy Leaving Skid Marks

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    .....

    a difference doesnt mean it's knocking on the lower fuel...

    all aussie cars will run on 91+ octane, but they market their power figures using 98 octane...

    so your new SS commodore will get 260kw on 98 octane, but on 95 it might be 250kw, and 91 it might be 235kw... doesnt mean it's knocking though.



    on the bonnet of my 33, it had a sticker saying 95 RON minimum... i used to use BP ultimate regardless, but one day i had to use caltex vortex 95, and it ran like crap, but didnt ping.
     
  13. mallen

    mallen Leaving Skid Marks

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    Thar ya go, I didn't know you had to retune and stuff... I feel better now...
     
  14. __ET__

    __ET__ Guest

    Won't the car just retune itself depending on what fuel you use?
     
  15. anon

    anon Guest

    Depends on the definition of tune. All the ECU will do is retard the ignition timing on detection of knocking. Fuel maps etc will stay the same....as far as I know anyways. It will do the best it can but may not stop detonation...and won't stop pre-ignition.
     
  16. Blainey

    Blainey Guest

    100 octane fuel (ethanol based fuels)

    In regard to 100 octane fuel. It is blended up to 100 octane using ethanol which has bound oxygen in it's chemical makeup. When this is burnt and runs through to your oxygen sensor it gives a higher oxygen reading than what was true and hence your ECU tries to adjust your AFR to its map and starts running rich. If you use ethanol based fuels you should have an aftermarket ECU or piggyback to adjust your fuel trims.

    More than likely you will not get optimum running conditions from fuels with ethanol unless your car is tuned for it.

    Just a few things I've learnt from industry experience. I used to be a Chemist for Caltex and Shell.
     
    Last edited by a moderator: Dec 14, 2007
  17. Blainey

    Blainey Guest

    My preference for fuel is 98 octane from BP. I still have industry contacts and this seems to be best. In fat when I was working for caltex I used BP fuels. Then when with shell I got 25% off so I didn't care so much about the economy.
     
  18. SiliconAngel

    SiliconAngel 1 AYC Bar

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    Hahaha great call ;)

    Thanks for the info Aaron, there's a lot to be said for expert opinion :D
     
  19. Dr_Josh001

    Dr_Josh001 Leaving Skid Marks

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    Just a question regarding this... I've been filling up using the 95 ethanol cheap stuff from IFS. I'm not sure if I can hear correctly but in the higher rev range I think the engine is pinging. When fueling up with normal 95 oct I don't hear this. I thought though that the knock sensor would pick up the pinging and cut power? Is pinging knocking? Or have I got my wires crossed?:confused:
     
  20. SiliconAngel

    SiliconAngel 1 AYC Bar

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    Knock = detonation = pre-ignition = pinging. This occurs when the fuel is exploding in the cylinder chamber instead of the slow burn / expansion that's intended. See the Wikipedia page here for a full description.

    The problem you have is the ECU is confused by a number of parameters. Which does it listen to, the knock sensor or the O² sensor? Remember VR4's weren't designed with ethanol fuels (or indeed mixtures) in mind, so their sensors can't cope with the by-product of ethanol fuel combustion and the ECU doen't understand the signals it's receiving.

    If you MUST use ethanol fuel blends, you'll need an aftermarket ECU and wideband sensor and new fuel lines and pump, or you'll run into trouble, probably sooner rather than later, but eventually you WILL have some serious issues. If you're getting detonation now, I daresay you'll kill your engine well before you have to worry about cracked fuel lines though...

    Just to drive the point home (and in case you didn't read the wiki page above) detonation causes catastrophic pressure and heat buildup within the engine, up to four times higher than the engine was designed for. That's quite apart from the problems caused by ignition happening at the wrong time during the combustion cycle (forcing rods backward against the drive line). You can end up with warped or cracked heads, damaged valve and lifter assembly or maybe even a snapped rod sticking out the side of your block.

    Running lower than 98 octane fuel is a bad idea because these engines run hot in standard configuration. Running a higher boost with a lower octane fuel is a recipe for disaster. Running higher boost with lower octane fuel containing ethanol is catastrophically, irreparably damaging.
     

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