1984 Mondial QV UK version | Page 2 | FerrariChat

1984 Mondial QV UK version

Discussion in 'Technical Q&A' started by Philjay50, Aug 27, 2020.

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  1. Philjay50

    Philjay50 Formula Junior

    Jan 16, 2003
    595
    Chester, England
    Full Name:
    Philip
    Ok, typical of me, now that I have one thing sorted out I have another small issue that I hope you may be able to help me with. Coming from the air intake vent are a two or three smaller (than the air intake) ports, where do these pipes vent to. It looked like one goes to the rear of the engine and aims at the exhaust, with that logic I am guessing that one also goes to the front bank but what about the third? Thanks in advance.
     
  2. Philjay50

    Philjay50 Formula Junior

    Jan 16, 2003
    595
    Chester, England
    Full Name:
    Philip
    Right, I have that but I am wondering where the three pipes feed. It all looks a little haphazard.
     
  3. afterburner

    afterburner F1 Rookie
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    Jun 20, 2008
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    From what I know, you need to attach hoses:
    - big tube blows air at the alternator
    - front small tube blows air below the front header towards the starter motor
    - rear small tube blows air below the rear header towards the diff area
     
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  4. Philjay50

    Philjay50 Formula Junior

    Jan 16, 2003
    595
    Chester, England
    Full Name:
    Philip
    Got it, Thats kind of what I thought but it looks a bit Heath Robinson, but hey. Again thanks for the help. I am now about to check out my water leak.
     
  5. afterburner

    afterburner F1 Rookie
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    You're welcome
     
  6. theunissenguido

    theunissenguido Formula 3
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    Jan 21, 2004
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    Guido
  7. Philjay50

    Philjay50 Formula Junior

    Jan 16, 2003
    595
    Chester, England
    Full Name:
    Philip
    No, I don’t think so, that one is already in place and it is fitted exactly as shown, it goes from the rear of the alternator backing cowl and just points down. I wondered if on of the pipes blew air to the front of the alternator and is extracted via the pipe shown. Does that make sense?
     
  8. afterburner

    afterburner F1 Rookie
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    Guido, I think it is what I said - big tube blows air at the alternator

    The alternator itself sucks air up from below the car through the pipe attached to it's back - the fan behind the pulley is sucking air out, not blowing in:

    Image Unavailable, Please Login

    Or am I interpreting the fan's blade and rotation direction incorrectly?
     
  9. Philjay50

    Philjay50 Formula Junior

    Jan 16, 2003
    595
    Chester, England
    Full Name:
    Philip
    For what it’s worth my logic says that the fan draws the air in and is expelled via the hose at the rear, in my head it makes sense that way with one of the hoses directing air to it. I will of course stand corrected.
     
  10. afterburner

    afterburner F1 Rookie
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    look at the arrow on the fan and the orientation of the blades.
     
  11. theunissenguido

    theunissenguido Formula 3
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    Jan 21, 2004
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    Yes sucks air trough the alternator direction pulley.
     
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  12. Philjay50

    Philjay50 Formula Junior

    Jan 16, 2003
    595
    Chester, England
    Full Name:
    Philip
    Having just spent the afternoon underneath the car having a look at the air intake it makes more sense for it to suck though the fan. I have been trying to sort out a water leak just in front of the front headers (if that makes sense). I think I now qualify as a gynaecologist.
     
  13. afterburner

    afterburner F1 Rookie
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    Yes, the question is in which direction. Could you post a picture of your fan?

    For cooling purposes, sucking in hot air from the header/exhaust area behind the alternator doesn't make a lot of sense to me.
    Why would you collect and then deviate below the car a tiny quantity of "hot" alternator exhaust air expensively (alloy casting, fire-resistent tube, brackets) from an area with a red-hot exhaust header?
     
  14. afterburner

    afterburner F1 Rookie
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    Let try to explain - and I am happy to stand corrected if someone knows better.

    To help understand what's happening imagine the fan blades on the other side of the star - it's more intuitive. You can see that the inclined blades "push" the air down toward the centre of the fan:
    Image Unavailable, Please Login

    Normal rh turning alternators such as ours have the blades attached the the other side of the star, so the opposite effect happens - air gets drawn from the centre of the fan with identical sense of rotation as above - the reverse effect:

    Image Unavailable, Please Login
    The reason for this direction of airflow is 3 fold: It cools the heat-sensitive diodes in the back of the alternator first with cool air, it's easier to attach the fan to the front main axis compared to the back and finally, fans work better sucking than pushing.
    That's why all new cars have the fan packs behind the radiators. (pushing air onto a radiator = resistance slows it down and increases its pressure; sort of a traffic jam between the fan blades and the radiator surface. Sucking from behind the resistance drops the air pressure behind by accelerating the air through the fan - in front it's necessarily higher - thus "liquifying" the air, which then can be drawn through the radiator more easily. See the also the P51 variable fuselage outlet, which creates that pressure drop speed dependant).
     
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  15. Philjay50

    Philjay50 Formula Junior

    Jan 16, 2003
    595
    Chester, England
    Full Name:
    Philip
    Wow all this info, thanks to all, I have been giving this a lot of though, especially Afterburners last post with the diagrams. Now I am in no position to argue but it does defy my logic that the fan will suck the air through the pipe at the back and expel it out of the front, I say this only because if you look at the attached photo you will see a shield to the right of the alternator that comes across at an angle, now just above and to the right is a vent from the air scoop pointing in the direction of the front bank and alternator. I did try to take a picture but I need to get under the car to make it worth while and I am not in working clothes at the moment.
    I have attached a picture and apologise for the state of the engine etc but the car is stuck in the workshop and I cannot move it to clean at the moment, maybe later when the engine is running.
    Just had a thought, I am hoping to get the engine running this weekend and I have some smoke capsules here somewhere, I will light up one of those and see which way the air flows.
     

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