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Thread: Is sealing up the joints in the stock air intake on a Puma a bad move?

  1. #1
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    Is sealing up the joints in the stock air intake on a Puma a bad move?

    A few weeks ago I pushed my limits regards maximum water depth I could push my fairly stock MY2013 110DC through. (There is a link to another thread about that exploit below, video link also there)

    Vehicle was due for servicing and so a few days later all the oils were changed and air cleaner serviced. I expected to see evidence of water in the airbox and was not disappointed. Water got in, got out again - as only it should apparently by design.

    In the linked thread I explain I have no intention to push such limits in normal use, nor fit a snorkel, just stay well clear of the need.

    I did have a think though about sealing up the few joints in the stock dirty air duct. And that is the purpose of this thread. Like to pick the brains of all you - the brains trust.

    My thinking on why it may be a bad thing to seal up the joints in the stock air intake (where one is not considering deep dunkings):

    - if the primary intake vent in the side of the fender were to get slapped by a wave (for example) a "leaky" intake duct would allow air to be drawn in via other paths (gaps in joints not underwater).

    - imagine for a moment the unsealed stock duct is somehow similar to a well designed multi-intake path air supply duct.

    - water is denser than air and so if there are multiple air paths, when one is briefly covered by water, air will still flow in via other paths

    - while water may enter parts of the ducting it is not going to be so forcibly "sucked" in, as would happen if all joints were sealed

    - think of it (unsealed intake duct) like when the straw you are drinking your milkshake with splits and let's air in ... No matter how you suck you only get air

    - by comparison if the dirty air intake were perfectly sealed from airbox to fender opening - that wave that slaps the fender covering the intake opening for a bit will be forcible sucked in.

    Thoughts?


    (The link mentioned above)
    http://www.aulro.com/afvb/90-110-130...-defender.html

  2. #2
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    Sealing up the joints is never a bad move. Water always finds a path. However your thoughts are flawed in that even on full acceleration the inlet pressure pre turbo is always at or around atmospheric, possibly slightly less. if the inlet is covered with water it will course the obstruction that lowers the inlet pressure thereby coursing the out side air pressure to push the water in (there is no such thing as suck!) if you have leaky joints they will suck (i know, it doesn't exist) an amount of air but really, the amount of water will be the problem, not that you have a little bit of air also.
    If you are submerged in water over the pipe work it will seep in past the poor sealing and get caught in the airflow and work its way though the system. as long as the wing vent is unobstructed water will not be sucked in.

    In short, seal the pipe work. And fit a snorkel, its cheap insurance.

  3. #3
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    Quote Originally Posted by landy View Post
    ...if the inlet is covered with water it will course the obstruction that lowers the inlet pressure thereby coursing the out side air pressure to push the water in (there is no such thing as suck!) if you have leaky joints they will suck (i know, it doesn't exist) an amount of air but really, the amount of water will be the problem, not that you have a little bit of air also.
    In my puma the gaps/air leaks are so "bad"(? Not sure yet it's such a bad thing) that
    - if I place a single sheet of A4 over the intake grill on the fender, there is barely enough vacuum pulled to support the weight of the paper at idle and zero noticable change to the engine.
    - while blocked completely I can run right through the rev range driving around the neigbourhood with no noticeable impact on performance.

    So my perception is that any water presenting itself to the intake grill will have, at the moment, very little atmospheric pressure urging to go further than the grill opening. That changes if I seal up all the air leaks ("alternate air intake paths").

    This is my way to explain your that comment that a little air won't make a difference doesn't fit the amount of air leakage apparently present. It's more like a LOT of air can enter via alternate paths (if I don't seal them up) meaning water at the intake grill gets far less attraction to my turbo than you'd apparently imagine

    Remember that I am talking here about an operating scenario that will include maybe 90% or more of LR owners, including definitely me by clear decisions I will make in future: I.e. Those rarely ever tackling water near the 500mm stated in manuals as maximum. So even the suggestion to get a snorkel as cheap insurance would be wasted investment.

    It is in this environment I am thinking that sealing up all the leaks in the ducting just makes me a little more vulnerable to a rogue splash on the intake vent. (Or rolling on to the right side into a 6" puddle... Yer yer stretching it...)
    Last edited by tact; 11th February 2015 at 07:11 PM. Reason: Added the "Remember ..." paragraph

  4. #4
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    I can't say that I understand 100% what you mean but I stand by what I said:-

    seal the pipe work. And fit a snorkel, its cheap insurance.

    Its tried and tested and (usually) done for a good reason. Because the owners are looking to the future "Just in Case"

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