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Thread: Can I remove these fuel expansion tanks?

  1. #1
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    Can I remove these fuel expansion tanks?

    Can I remove these fuel expansion tanks?



    Please can someone let me know if these 2 parts can be removed. From what I can see they don’t do much and are just rust traps?

    I plan to blank off the outlets in the fuel tanks that connect to these parts?

    Is this possible?

    Thanks

    Martin

  2. #2
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    having rebuilt my torana with a 120L drop tank I can tell you that fuel expansion tanks are pretty important.

    As fuel gets warmer it expands, this excess fuel has to go somewhere, this is where these tanks come in to play. if you remove them and block them off the fuel will find another way out as it will pressurise in the tank. this can not only lead to fuel delivery issues but also, best case scenario is you will develop some leaks at the fuel tank end. worst case is fuel will start leaking at the engine end on all the hot bits....In my toranas case, fuel used to pressurise and make its way through the line to the pollution canister and then out the bottom in my engine bay, it wasnt dangerous, but you dont want a puddle of fuel forming when you're standing at the lights.

    hope this helps
    2008 POLO GTI - SOLD
    2005 MkV Golf GTI - couldn't resist

  3. #3
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    Both are important. The expansion tank is there to allow for expansion when you fill the tank, even to just the first cut off point.

    The Charcoal filter is required to meet emission standards. It takes fuel vapours from the tank. The fuel tank filler opening is sealed, and as the fuel expands, vapours are forced out. As fuel is used, air has to be drawn in to prevent the tank collapsing. This is done via the charcoal filter and this also re-charges the charcoal.

  4. #4
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    Quote Originally Posted by AUC-05L View Post
    having rebuilt my torana with a 120L drop tank I can tell you that fuel expansion tanks are pretty important.

    As fuel gets warmer it expands, this excess fuel has to go somewhere, this is where these tanks come in to play. if you remove them and block them off the fuel will find another way out as it will pressurise in the tank. this can not only lead to fuel delivery issues but also, best case scenario is you will develop some leaks at the fuel tank end. worst case is fuel will start leaking at the engine end on all the hot bits....In my toranas case, fuel used to pressurise and make its way through the line to the pollution canister and then out the bottom in my engine bay, it wasnt dangerous, but you dont want a puddle of fuel forming when you're standing at the lights.

    hope this helps
    Thanks AUC-05L
    Sounds like I best reinstate em! Thanks for the detailed explanation.

    Quote Originally Posted by wai View Post
    Both are important. The expansion tank is there to allow for expansion when you fill the tank, even to just the first cut off point.

    The Charcoal filter is required to meet emission standards. It takes fuel vapours from the tank. The fuel tank filler opening is sealed, and as the fuel expands, vapours are forced out. As fuel is used, air has to be drawn in to prevent the tank collapsing. This is done via the charcoal filter and this also re-charges the charcoal.
    Funny enough I don’t actually have a Charcoal filter although I’ve asked if it can be removed. Someone had previously removed it. It looks like I better find a replacement and reinstate too!
    Thanks for the feedback.

  5. #5
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    Quote Originally Posted by Drysponge View Post
    Funny enough I don’t actually have a Charcoal filter although I’ve asked if it can be removed. Someone had previously removed it. It looks like I better find a replacement and reinstate too!
    Thanks for the feedback.
    There are two ways to capture vapour emissions. One is to have a charcoal filter, and the other is to plumb it into the positive crankcase ventilation system. The Gemini used to have it connected to the PCV system.

    You can't go changing it yourself however. If it originally had a charcoal filter, then you can't remove it and connect it to the PCV system.

  6. #6
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    Marty,

    From memory ( cause I cant read your images easily) there is a hose and one way valve that connects the Charcoal cannister to the engine inlet ducting, this allows engine vacuum to suck the fuel vapours that have collected in the canister out into the engine to be burnt and basically purges any of the expansion vapours from the canister setting it to be able to filter tank fumes as required.

    Certain versions of Kjet engines use to have a slight pressurisation of the tank, maybe to stop foaming / bubble formation of the tank contents.

    HTH, to many peeps remove all the emissions stuff without fully understanding operation of the unit.
    Lots of MK 1 Scirocco's...

    If it aint a MK 1 then it must be a donor car ??

    Cheers,
    Grant...

  7. #7
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    Quote Originally Posted by roccodingo View Post
    Marty,

    From memory ( cause I cant read your images easily) there is a hose and one way valve that connects the Charcoal cannister to the engine inlet ducting, this allows engine vacuum to suck the fuel vapours that have collected in the canister out into the engine to be burnt and basically purges any of the expansion vapours from the canister setting it to be able to filter tank fumes as required.

    Certain versions of Kjet engines use to have a slight pressurisation of the tank, maybe to stop foaming / bubble formation of the tank contents.

    HTH, to many peeps remove all the emissions stuff without fully understanding operation of the unit.
    Thanks Grant,

    Useful information….. Best get myself down a wreakers yard if I can find one with a MK1 golf in it and pick one up!

    Thanks
    Martin

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