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Thread: Snorkel or not?

  1. #101
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    Default Re: Snorkel or not?

    Quote Originally Posted by Walnut View Post
    Dunno about that. My car is always covered in dust inside. My back windows are dusty, but nothing compared to my engine bay.

    Could be that it's older, maybe newer cars have better seals to prevent dust ingress? Could be an interesting test to see if newer vehicles benefit from a snorkel.
    My 19 year old Isuzu and 11 year old JMC have no dust ingress at all with windows closed and air con running while driving bad Karoo roads.
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  2. #102
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    Default Re: Snorkel or not?

    Quote Originally Posted by cor View Post
    Sorry to say but if pressure change everything changes , in a non turbo car the breathing will improve , turbo car it should cancel the disadvantages of the restrictions in the snorkel , what youíre trying to tell me is that the only way of getting more water out of a 20mm pipe is to change it to a 25mm irrespective of the pressure and that is simple not true .
    Water and air are very different mediums. Air is compressible and water is not. Water flow will require exponential pressure increases to speed it up. I have had to replace a positive displacement screw pump with a less powerful model because someone thought that he could increase the cooling water flow by adding a more powerful pump without increasing pipe diameter. It just kept tripping on startup. Examination indicated the pump curve caused the pressure to rise high enough to trip the pump. Expensive lesson for him.
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  3. #103
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    Default Re: Snorkel or not?

    Quote Originally Posted by Olyfboer View Post
    Nope. Windows shut and air con on. The dust on the rear window is due to aerodynamic drag, not because it gets that high. Have a look at a vehicle at speed on a dirt road. The dust hardly gets as high as the rear bumper. The drag at the back makes it get to window height.
    Talking about dust in convoys, which apparently never gets to snorkel height.


  4. #104
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    Default Re: Snorkel or not?

    I have a snorkel because my vehicle came with it. It must be better for the air filter. I do not think it is esthetic! And even with it, I would not got in water

  5. #105
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    Default Re: Snorkel or not?

    Quote Originally Posted by mikeml View Post
    What pressure? Of course more pressure moves more medium through the same pipe. If you are talking about the ram effect of the snorkel, then you will find that there is nothing quantifiable at our speeds, which are often much slower than the max legal speed. I can't remember what the calcs revealed exactly, but there was virtually nothing at 120km/hr, and speeds needed to get much closer to 200km/hr before the ram effect became noticeable.

    This is one of the reasons why the guys who experimented with turning their snorkels backwards found no decrease in power.
    I would say no measurable decrease in power . Basic physics will tel you otherwise , put your hand out of a moving vehicle and you will feel the pressure I am talking about
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  6. #106
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    Default Re: Snorkel or not?

    Quote Originally Posted by Olyfboer View Post
    Water and air are very different mediums. Air is compressible and water is not. Water flow will require exponential pressure increases to speed it up. I have had to replace a positive displacement screw pump with a less powerful model because someone thought that he could increase the cooling water flow by adding a more powerful pump without increasing pipe diameter. It just kept tripping on startup. Examination indicated the pump curve caused the pressure to rise high enough to trip the pump. Expensive lesson for him.
    Compressed air create pressure
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  7. #107
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    Default Re: Snorkel or not?

    Quote Originally Posted by Olyfboer View Post
    Nope. Windows shut and air con on. The dust on the rear window is due to aerodynamic drag, not because it gets that high. Have a look at a vehicle at speed on a dirt road. The dust hardly gets as high as the rear bumper. The drag at the back makes it get to window height.
    Well you see this is the point Iím trying to make. Saying my engine bay is dusty, but the roof of my car isnít, therefore the air going into the engine bay is dustier than the air going over the roof is plain wrong, the aerodynamics are far more important.

    Obviously there are good and bad places to be sucking air from if youíre worried about dust. The top of the drivers A pillar is probably much better than inside the front wheel wheel arch for instance. But I canít see how the air at the front lights is going to be dustier than that going over roof. Itís the same air, go look at the vapour trails on any wind tunnel test pictures to see what I mean.

    The suction on any positive displacement pump, which a piston engine is, is critical. Adding delta P to the suction causes issues. Because a car engine is pumping air itís far more forgiving, but it will cause issues. One of the biggest drivers of excessive EGT as I understand it, but I have no personal experience, is a blocked air filter. Any pipe you add to front of the air filter will cause a pressure drop at the filter housing inlet. The amount of pressure drop is related to the design of the snorkel. This is easy to see for yourself. Get a snorkel, a diving one, now get a hose pipe, try breathing through each. Keep in mind that a lot of the snorkel research has probably been done at sea level, like the one from ARB listed above, ainít no Highveld in Australia.

  8. #108
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    Default Re: Snorkel or not?

    Quote Originally Posted by cor View Post
    I would say no measurable decrease in power . Basic physics will tel you otherwise , put your hand out of a moving vehicle and you will feel the pressure I am talking about
    Quote Originally Posted by BruceB View Post
    Well you see this is the point Iím trying to make. Saying my engine bay is dusty, but the roof of my car isnít, therefore the air going into the engine bay is dustier than the air going over the roof is plain wrong, the aerodynamics are far more important.

    Obviously there are good and bad places to be sucking air from if youíre worried about dust. The top of the drivers A pillar is probably much better than inside the front wheel wheel arch for instance. But I canít see how the air at the front lights is going to be dustier than that going over roof. Itís the same air, go look at the vapour trails on any wind tunnel test pictures to see what I mean.

    The suction on any positive displacement pump, which a piston engine is, is critical. Adding delta P to the suction causes issues. Because a car engine is pumping air itís far more forgiving, but it will cause issues. One of the biggest drivers of excessive EGT as I understand it, but I have no personal experience, is a blocked air filter. Any pipe you add to front of the air filter will cause a pressure drop at the filter housing inlet. The amount of pressure drop is related to the design of the snorkel. This is easy to see for yourself. Get a snorkel, a diving one, now get a hose pipe, try breathing through each. Keep in mind that a lot of the snorkel research has probably been done at sea level, like the one from ARB listed above, ainít no Highveld in Australia.
    COR, the pressure from the RAM effect needs to overcome the pressure drop Bruce is talking about. The snorkel introduces this extra pressure drop which was not there before. The higher the engine revs, the bigger the pressure drop. This is the reason the RAM effect only comes into play at high speeds. It does not play a role on our vehicles, even with the standard scoops facing forwards.

    I'm not anti snorkel. It has it's uses, like with water crossings and the cool look factor. And like Estee pointed out, it can help with certain cars to reduce dust intake to the airfilter, which is a positive thing where their airfilters are possibly a bit small for dusty environments and where the filter pickup point is in a bad spot.

    On Defenders with the air pickup point on the outside behind the wheelarch a snorkel does not help with less dust, and certainly not with lower air temperatures. Also, as someone pointed out, in most moving vehicle the air temperatures are not that high in the engine bay, so claims of lower air temperatures is also a myth in these vehicles. At slow speeds, when temperature can get high in the engine bay, generally low throttle settings are used, and lower air temps will not play a role.

    I might install one on my camper, but not because of water crossings, or the cool look factor, and not because of the cleaner air either. But because of the cooler air. On this vehicle, the fresh air coming into the engine bay is restricted to a very small aperture in front of the radiator. It was designed for cold European climates. Temperatures in the engine bay can get higher than in eg the Defender I had. A big negative of the snorkel is cleaning the windscreen. Being a tall vehicle, it is difficult enough cleaning the windscreen without another obstruction.


  9. #109
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    Default Re: Snorkel or not?

    Quote Originally Posted by cor View Post
    Compressed air create pressure
    It looks like there might be a terminology problem here:

    Compressing air will create pressure. Compressed air is at pressure.

    Water cannot be compressed but can be pressurised. Less than a drop of water released from valve on a pressurised vessel will drop the pressure to ambient immediately. Opening a valve on a vessel pressurised by air will result in it expanding and being released until the pressure is at ambient.

    The mediums are different and the dynamics of air or water flow in the same pipe are completely different.
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  10. #110
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    Default Re: Snorkel or not?

    As I mentioned before does anyone know a manufacture that sells a 4x4 with a snorkel as standard ? The Dakar race I never saw any Snorkels on any vehicles
    Last edited by 12richardk; 2020/01/15 at 05:52 PM.
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  11. #111
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    Default Re: Snorkel or not?

    Quote Originally Posted by Olyfboer View Post
    It looks like there might be a terminology problem here:

    Compressing air will create pressure. Compressed air is at pressure.

    Water cannot be compressed but can be pressurised. Less than a drop of water released from valve on a pressurised vessel will drop the pressure to ambient immediately. Opening a valve on a vessel pressurised by air will result in it expanding and being released until the pressure is at ambient.

    The mediums are different and the dynamics of air or water flow in the same pipe are completely different.
    I no the mediums are different and the dynamics are different , but the principle is the same , if you force more air in a pipe more air will come out on the other side and if you block that pipe you will create pressure irrespective if itís water or air . That is exactly what a turbo does . What I am trying to say is that the RAM effect ( as been explained to me ) should overcome the restriction on the air intake a snorkel will create and at a much lower speed than have been mentioned here . I also no that the RAM effect will only enhance the performance on a much higher speed
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  12. #112
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    Default Re: Snorkel or not?

    Quote Originally Posted by 12richardk View Post
    As I mentioned before does anyone know a manufacture that sells a 4x4 with a snorkel as standard ? The Dakar race I never saw any Snorkels on any vehicles
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  13. #113
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    Default Re: Snorkel or not?

    Quote Originally Posted by 12richardk View Post
    As I mentioned before does anyone know a manufacture that sells a 4x4 with a snorkel as standard ? The Dakar race I never saw any Snorkels on any vehicles
    The 70s LC and the LC 200 that Toyota sell here can come in an 'NGO spec' that has a factory Toyota snorkel.

  14. #114
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    Default Re: Snorkel or not?

    Quote Originally Posted by 12richardk View Post
    As I mentioned before does anyone know a manufacture that sells a 4x4 with a snorkel as standard ? The Dakar race I never saw any Snorkels on any vehicles
    And the Force Ghurka but not available in RSA yet but that could change

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  15. #115
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    Default Re: Snorkel or not?

    Because they dont care. Those things get changed every night in the bivouac.

    And the snorkels are incorporated on the bodywork somewhere where they get the max airflow and least dust, cause they have to money to do R&D

  16. #116
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    Default Re: Snorkel or not?

    You can't really look at a Dakar car for comparison, those things are flipping modified to the extreme. That's like looking at Ken Blocks Fiesta and thinking it's actually a Fiesta.

    The latest review from 4wd Action shows how bad a VW's pickup is. And the Dmax looks like it came from factory with a snorkel.
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  17. #117
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    Default Re: Snorkel or not?

    Quote Originally Posted by Walnut View Post
    You can't really look at a Dakar car for comparison, those things are flipping modified to the extreme. That's like looking at Ken Blocks Fiesta and thinking it's actually a Fiesta.

    The latest review from 4wd Action shows how bad a VW's pickup is. And the Dmax looks like it came from factory with a snorkel.

    "Bad"?

    Eish!
    Last edited by hatjohan; 2020/01/17 at 08:06 AM.



  18. #118
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    Default Re: Snorkel or not?

    Quote Originally Posted by hatjohan View Post
    "Bad"?

    Eish!
    Ya, watch the video they talk about how it's front facing. That's where a good snorkel would benefit that car.
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  19. #119
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    Default Re: Snorkel or not?

    Quote Originally Posted by 12richardk View Post
    As I mentioned before does anyone know a manufacture that sells a 4x4 with a snorkel as standard ? The Dakar race I never saw any Snorkels on any vehicles
    The Mercedes G class 300CDI profesionnal was sold with the snorkel.

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