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portal pat



Member Since: 05 Jan 2015
Location: South. Very south.
Posts: 36

Australia 2001 Defender 110 Td5 SW Fuji White
Snorkel flow rates.
Has anyone done any flow testing on snorkels? I'm talking about over the counter units, not bespoke. Thanks in advance. Nothing suggests poor workmanship like wrinkles in the duct tape.
Post #1046096 18th Sep 2024 12:18pm
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34064



Member Since: 12 Dec 2023
Location: South Central
Posts: 190

United Kingdom 2003 Defender 110 Td5 HT Alaska White
I have the cheapo Britpart one and I'm thinking between that and the LR ducting it's proving a bit of a choke point 110 Td5 Ex Utilities slowly converting into a pop top camper one day

Build thread:https://www.defender2.net/forum/post1024784.html#1024784
Post #1046219 19th Sep 2024 4:58pm
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Chicken Drumstick



Member Since: 17 Aug 2020
Location: Near MK
Posts: 749

United Kingdom 
Considering the size of the tube on most snorkels and that they are basically just a tube and given the cfm requirements for the power levels of most Land Rover's, I'd be most surprised if they represented any kind of restriction to any meaningful amount.
Post #1046238 19th Sep 2024 8:13pm
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portal pat



Member Since: 05 Jan 2015
Location: South. Very south.
Posts: 36

Australia 2001 Defender 110 Td5 SW Fuji White
Should have said, my TD5 has a lot of power. Not stock. Nothing suggests poor workmanship like wrinkles in the duct tape.
Post #1046244 19th Sep 2024 10:15pm
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jimbo55



Member Since: 15 Jul 2020
Location: Midlands
Posts: 399

United Kingdom 
Pete bell did some testing years back

Snorkels are a lot more restrictive than you’d think, even if the diameter is the same as the existing pipework, the fact the length increases significantly is where the main impact is.
Post #1046258 20th Sep 2024 8:54am
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mturri



Member Since: 13 Jul 2010
Location: All over
Posts: 33

 2006 Defender 110 Td5 CSW Bonatti Grey
Re: Snorkel flow rates.
portal pat wrote:
Has anyone done any flow testing on snorkels? I'm talking about over the counter units, not bespoke. Thanks in advance.

Did some modelling work on friction losses (*), standard vs raised air intake; what are you after?

(*) AAP sensor seats inside air filter box, so at constant atmospheric pressure, reduction in measured AAP is roughly equal to intake friction losses (including that across air filter as AAP sensor is on downstream side). 24 yrs of Td5 ownership
D110 Td5 MY06 fully tuned up
ex-D2 Td5 MY04 Auto
ex-D110 Td5 MY00
ex-D2 Td5 MY00
ex-D2 Td5 MY99
ex-D1 300Tdi MY89
ex-D90 200Tdi MY87
Post #1046399 21st Sep 2024 3:56pm
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custom90



Member Since: 21 Jan 2010
Location: South West, England.
Posts: 20412

United Kingdom 
Basically wherever you have the narrowest aperture, which is the narrowest tubing or point in the inlet pipework, is the smallest restriction and any extreme angles add to flow delay.
So you want to aim for the largest dia apertures / pipework that is feasible, with a sweeping smooth angle where possible, so a 45 degree angle is far better than a 90 degree bend where possible.

I don’t think there is much point in increasing the diameter significantly larger than the air box entry or exit whatever it may be.

You can get scientific with it with air mass and flow etc if you want to, a nice smooth tube and smooth bends aide flow with less obstruction, it can pay to try and spin the incoming airflow, but in doing that you can add a little restriction in itself.
Does however, create a cyclone effect, but again that is easily lost if the inlet isn’t smooth and sweeping.

You can get a ram air effect as well like I get with a Safari, but for example a Mantec RAI doesn’t do that.

The only way I think you can test these things is by air metering and specs, which is easier said than done in real world situations.
One thing for sure is guaranteed, the LR black plastic pipework behind the wing IS restrictive. $W33T $0U7H3RN $UG4R
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Post #1046423 21st Sep 2024 8:21pm
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portal pat



Member Since: 05 Jan 2015
Location: South. Very south.
Posts: 36

Australia 2001 Defender 110 Td5 SW Fuji White
Re: Snorkel flow rates.
[quote="mturri"]
portal pat wrote:
Has anyone done any flow testing on snorkels? I'm talking about over the counter units, not bespoke. Thanks in advance.

Did some modelling work on friction losses (*), standard vs raised air intake; what are you after?

(*) AAP sensor seats inside air filter box, so at constant atmospheric pressure, reduction in measured AAP is roughly equal to intake friction losses (including that across air filter as AAP sensor is on downstream side).[/quote
I have a VNT turbo along with all that needs to go with that and am currently running a Safari snorkel. I'm wondering whether there are any other snorkels that flow better? Nothing suggests poor workmanship like wrinkles in the duct tape.
Post #1046434 21st Sep 2024 11:13pm
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portal pat



Member Since: 05 Jan 2015
Location: South. Very south.
Posts: 36

Australia 2001 Defender 110 Td5 SW Fuji White
custom90 wrote:
Basically wherever you have the narrowest aperture, which is the narrowest tubing or point in the inlet pipework, is the smallest restriction and any extreme angles add to flow delay.
So you want to aim for the largest dia apertures / pipework that is feasible, with a sweeping smooth angle where possible, so a 45 degree angle is far better than a 90 degree bend where possible.

I don’t think there is much point in increasing the diameter significantly larger than the air box entry or exit whatever it may be.

You can get scientific with it with air mass and flow etc if you want to, a nice smooth tube and smooth bends aide flow with less obstruction, it can pay to try and spin the incoming airflow, but in doing that you can add a little restriction in itself.
Does however, create a cyclone effect, but again that is easily lost if the inlet isn’t smooth and sweeping.

You can get a ram air effect as well like I get with a Safari, but for example a Mantec RAI doesn’t do that.

The only way I think you can test these things is by air metering and specs, which is easier said than done in real world situations.
One thing for sure is guaranteed, the LR black plastic pipework behind the wing IS restrictive.


I run a Safari snorkel and initially had a Donaldson pre filter atop that. Changed to a regular snorkel intake and felt as though I gained a little torque rise. Nothing suggests poor workmanship like wrinkles in the duct tape.
Post #1046435 21st Sep 2024 11:16pm
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Jabberwocky



Member Since: 27 Oct 2021
Location: Luxembourg
Posts: 223

Luxembourg 
I have a cyclonic head on my raised air intake and I think it has done its job well on various dusty trips I’ve done, but I do wonder if it’s too restrictive, I have a heavy camper and it does seem to struggle more than it should on hills and I think the engine is working too hard. I’ve decided to reinstate the OEM side grille but leave the pipe up the A pillar in place so I can switch between the 2 as needed. I have no more dusty trips planned until our big trip in 2026 so the raised intake is unnecessary.
Post #1046468 22nd Sep 2024 12:22pm
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