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  1. #21
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    Default Re: Snorkel - Facing forward or backwards

    Quote Originally Posted by Rebel 4x4 View Post
    Donít forget the manly 4x4 look of your ride (my primary focus as we have a water crisis)
    Indeed! Why fit or modify anything to make it look crap.
    Ross

  2. #22
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    Default Re: Snorkel - Facing forward or backwards

    Quote Originally Posted by RMackay View Post
    Indeed! Why fit or modify anything to make it look crap.
    Sent from my iPhone


  3. #23
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    Default Re: Snorkel - Facing forward or backwards

    The claims of snorkel manufacturers and supporters are:
    - ram air effect/better performance
    - safer water crossings
    - cleaner air
    - cooler engine operation, etc.
    Here are some experiences with snorkels!
    !. Having the air intake in the second floor doesn't improve the performance of a CR Turbodiesel engine and there isn't less dust up there.
    2. It's better waterproofing everything else, e.g. breather tubes, electronics etc. Have seen off-roaders with snorkels fitted being stranded in about 600mm deep
    water!
    3. In hardcore off-roading a snorkel can become the first thing getting damaged.
    4. A cooler and better performing engine is great myth. A snorkel usually affects negatively the aerodynamics and so the fuel consumption.
    5. If you have or consider fitting a snorkel - don't drive in heavy rain with the water drain plug still in place and always make sure that the plug is in place when
    fording deep water!
    I'll never cut a hole in my new (third) 4x4 SUV!

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  5. #24
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    Default Re: Snorkel - Facing forward or backwards

    totally overrated piece of plastic.

    Id rather spend the money on a tracks for africa subscription

  6. #25
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    Default Re: Snorkel - Facing forward or backwards

    The Mercedes G Professional comes with the snorkel facing backwards.

  7. #26
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    Default Re: Snorkel - Facing forward or backwards

    Just wondering if this means anything? VW won't honor any warranty claim if snorkel faces to the front.



  8. #27
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    Default Ram effect

    Quote Originally Posted by mikeml View Post
    There is virtually no ram effect at the speeds we travel at...
    Ram effect can only add one to four psi depending upon the vehicle speed and design of the system. I'm running near 25 psi on my turbo. So, any ram effect would be nullified.
    Renault Duster 4WD Gen1: No Meow, GC = 254mm, WD = 820mm

  9. #28
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    Default Submarine?

    Quote Originally Posted by Stephan van Tonder View Post
    The sole purpose of a snorkel is to keep water out of the intake. ...
    I never noticed much difference but it sure worked in water crossings in my diesel landcruiser.
    It never drowned.
    ...
    Are you saying that your snorkel allowed you to do a water crossing where the water was above the highest point on your normal air intake system?
    Renault Duster 4WD Gen1: No Meow, GC = 254mm, WD = 820mm

  10. #29
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    Default Re: Snorkel - Facing forward or backwards

    Well if that isn't the point of a snorkel then you really are only fitting it for the looks isn't it?
    don't know - does water over the bonnet qualify?
    Last edited by Stephan van Tonder; 2018/02/13 at 09:39 AM.
    Audi Q7 - 3l TDi - 2010 - steel suspension - wife's daily
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  11. #30
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    Default Re: Snorkel - Facing forward or backwards

    Lots of opinion in this one. I have a bit of aero design experience from industry so give my opinion as well. Using the LC 70 series V8 as an example. Firstly, the snorkel system is NOT waterproof, so do not kid yourself this is a submarine. Take the underside of the airbox as the maximum wading depth, including the wave crest. ( and don't forget the other little things like a swamped starter motor, alternator and diffs).

    The top of the snorkel is a cyclonic pre-filter-for air, and to expel any water that gets in before it runs down the duct. It is much more efficient at protecting the motor than the fashion jobs people replace them with. It is also well above the main dust belt. Pointing a plan open bend forward or backwards will make no positive influence on pressure in the intake system (the friction losses in the pipe take care of that), but the backward orientation may have negative impact, providing an area of low pressure behind the hood.

    If you wantt more intake pressure, buy a supercharger, not a snorkel hood.

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  13. #31
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    Default Elevated Intake Tube

    Thanks, that was my understanding that these systems are not waterproof even though some have one-way trap valves to let the collected water out.

    By diffs, I assume you mean the diff breathers. Also, spark plugs under water isnít so lekker for those other types of engines.

    Öand now for a discussion on the particle size impacting upon engines and the optimum intake height (and distance from the vehicle in front). Perhaps another term other than snorkel would be more appropriate.

    To me, blocking my cabinís intake to only breathe through a snorkel might make more sense.
    Renault Duster 4WD Gen1: No Meow, GC = 254mm, WD = 820mm

  14. #32
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    Default Re: Snorkel - Facing forward or backwards

    Personal experience, so don't shoot me...

    Built my snorkel after I drowned my Nissan Sani. Made sure it's 100% water proof and have been in water to over the bonnet.

    Expect no ram effect, but did manage to drop my intake temps at the airbox from the usual 35-50deg (depending on your speed) to nothing more than 1-2deg above ambient outside temperature. Makes a huge difference to my 2.7TD.

    Correct design should not allow water into your intake. Mine is a one piece head to pipe with approximate 3.5" pipe diameter up to the airbox intake, and I have never found water in my airbox. A dead bird, yes, but never water, or traces that the filter got wet.

    I confess that I don't do much offroading lately, but I doubled my filter change interval to 40k km town driving

    I'm convinced that my snorkel is an advantage on my vehicle, and actually don't really like the look of it. It did not turn out as good looking as I thought it would. But that was due to me chasing a pipe size that I thought would not cause a restriction.
    David/Hillbilly - 1997 SFA Nissan Sani 2,7 TD - 5" lift on 33" tires - Dual Transfer with 4.1 gears

    http://www.youtube.com/user/davidabcab



  15. #33
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    Default Re: Snorkel - Facing forward or backwards

    To me a snorkel is about the life of an airfilter. Toyota getting ridicules with their prices on air filters.
    Johan Kriel

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  17. #34
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    Default Re: Snorkel - Facing forward or backwards

    Quote Originally Posted by bfreesani View Post
    ...Built my snorkel after I drowned my Nissan Sani. Made sure it's 100% water proof and have been in water to over the bonnet.

    Expect no ram effect, but did manage to drop my intake temps at the airbox from the usual 35-50deg (depending on your speed) to nothing more than 1-2deg above ambient outside temperature. Makes a huge difference to my 2.7TD.

    Correct design should not allow water into your intake. Mine is a one piece head to pipe with approximate 3.5" pipe diameter up to the airbox intake, and I have never found water in my airbox. A dead bird, yes, but never water, or traces that the filter got wet.

    I confess that I don't do much offroading lately, but I doubled my filter change interval to 40k km town driving

    I'm convinced that my snorkel is an advantage on my vehicle, and actually don't really like the look of it. It did not turn out as good looking as I thought it would. But that was due to me chasing a pipe size that I thought would not cause a restriction.
    Just due to the temp drop, this project could be worthwhile.

    Any photos and design sheets? If it is a DIY, it must have cost less. I could get away with 3" tubing and prefer a washable a/f.
    Renault Duster 4WD Gen1: No Meow, GC = 254mm, WD = 820mm

  18. #35
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    Default Re: Snorkel - Facing forward or backwards

    As has been correctly pointed out before, a snorkel will never increase your power since the ram effect is negligible (if you want to work it out, find the forward speed in metres per second, square that number, halve the square and you have the pressure increase on pascals. 100,000 pascals equals a Bar. At 120km/h the pressure increase is 555 pascals, or 5mB.) The ram effect doesn't even come close to overcoming the partial vacuum left by air being sucked through the air-filter, which can often exceed 50mB, especialy when the filter is a little clogged and the engine is sucking hard.

    What a snorkel can do for you is prevent significant occasional power losses. The Ideal Gas Law PV = nRT tells us that the power output of a Turbo-Diesel (Petrol engines are different, as are non-turbo diesels) will potentially decrease by 10% when the ambient temperature rises from 0 to 30 degrees C. Similary the power output will decrease approximately a further 10% should the intake air temperature of a Turbo-Diesel increase by anotherr 30 degrees C.

    Intake ducts under the bonnet are arranged so that the intake air is drawn, as far as possible, from that which has not passed through the radiator, since the air coming through the radiator is always hotter by 30 to 40 degrees C than ambient. The intake duct tries to source air that has enterred the engine compartment by passing to the left or right of the radiator, and most of the time it succeeds.

    However at times when the engine is really working hard, such as pulling a caravan up the Hex Pass, the forward speed is low, and the fan is pulling a lot of air through the radiator and slightly elevating the ambient pressure under the bonnet, the airflow under the bonnet can be disrupted and hot air can be taken into the intake duct, thereby robbing the engine of another 10%, or more, of its power.

    You see this frequently with top-mounted intercoolers. The normal airflow through the scoop and downwards through the intercooler breaks down and the intercooler has its own version of 'reflux' when hot air from the radiator passes upwards through the intercooler. At times like this the air temperature in the intake manifold will rise above 150 degrees C. As soon as forward speed recovers this corrects itself.

    If the engine breathes through a snorkel this can never happen.

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  20. #36
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    Default Dry Ice

    So, I should put some dry ice in front of my intercooler the next time I pull a trailer up the Hex Pass.
    Renault Duster 4WD Gen1: No Meow, GC = 254mm, WD = 820mm

  21. #37
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    Default Re: Snorkel - Facing forward or backwards

    My first 4wd was a Land Rover. One day on a dirt road my wife was driving. We entered what appeared to be a shallow puddle. Much to our surprise the nose dropped down and water started pushing over the bonnet. The car started stuttering. I told my wife to floor it, which fortunately got us through and out the other side. Eventually the engine settled down as the water dried out. Later that day I opened things up and found that muddy water had entered the airbox and that it had got into the MAF. I cleaned out the dried mud and all was well. After that however I fitted a snorkel, extended breathers into pillars, waterproofed the distributor as best I was able and took various other steps. Subsequently the vehicle was used in a number of deep water crossings without a problem, the water on more than one occasion nearly touching the underside of the wing mirrors and pushing right up over the bonnet. Deep wading is really better avoided but sometimes there's not terribly much choice. I have no the slightest doubt that without the snorkel we would have been totally stuffed and drowned the engine.

    I think if dust is a concern, adding a cyclonic header is a good idea - they do work.

    As for ram effect, it always seemed to me that there was some over about 130km/h but it could have been my wishful thinking. I eventually reversed the snorkel head. Bugs were always getting into it and the air filter. I also found that putting shade cloth over the intake helps with grass seed when you are in long savannah grass - otherwise a ton of it ends up in the air filter, which would not normally be the case without a snorkel.

    Snorkels have their place IMHO but are not always justified.

  22. #38
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    Default Re: Snorkel - Facing forward or backwards

    Quote Originally Posted by Butch Dassie View Post
    Just due to the temp drop, this project could be worthwhile.

    Any photos and design sheets? If it is a DIY, it must have cost less. I could get away with 3" tubing and prefer a washable a/f.
    Unfortunately I'm not one of those guys that plans stuff on paper much. I build and break it, build again and cut it off, and eventually kinda end up with what I was hoping for... Frustrating I know...

    Name:  Photo130.jpg
Views: 750
Size:  113.5 KB

    But yes... as Fyko explained the gains from cooler air, I have experienced with moving my air intake around, and eventually installing the snorkel. The day I punched the hole in the side of the body, and passed the intake through it, I could feel and see improvement. The turbo reacts different as well. My madman screams at me more and more as temps drop outside. I have set it to alarm at 1bar with usual running peaking at 0.9bar. but as the temps decreases, boost spikes get worse. I have an intercooler I need to install, but some other projects are more important right now..
    David/Hillbilly - 1997 SFA Nissan Sani 2,7 TD - 5" lift on 33" tires - Dual Transfer with 4.1 gears

    http://www.youtube.com/user/davidabcab



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  24. #39
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    Default Heat Sink

    If it had a distributor, it must have had spark plugs. I've had spark plugs with cracked porcelain before. I wonder if a quick drop in temp could cause them to crack. You must have had good (watertight?) connection around the plugs' insulators.

    To raise the diff breathers seems straight forward...just add an extension of tubing.

    I wonder how one would go about making an alternator waterproof. I would imagine they generate some heat given that rectifiers often have big heat sinks.
    Renault Duster 4WD Gen1: No Meow, GC = 254mm, WD = 820mm

  25. #40
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    Default Re: Snorkel - Facing forward or backwards

    I've never had an issue with just plain water and an alternator, it's the mud that eats them up, and very fast. Solution is a water cooled unit, but they are expensive.
    David/Hillbilly - 1997 SFA Nissan Sani 2,7 TD - 5" lift on 33" tires - Dual Transfer with 4.1 gears

    http://www.youtube.com/user/davidabcab



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