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rallysteve



Member Since: 10 Feb 2014
Location: Cumbria
Posts: 2237

United Kingdom 2002 Defender 110 Td5 DCPU Keswick Green
Breather routing inside snorkel
Evening all,

Just after some opinions on this idea. Will be running all my breathers to a manifold under the bonnet but really dont want to have to run the pipe out of the bonnet and cable tie it to the snorkel. Debating putting a pneumatic bulkhead fitting into the lower half of the airbox (pre-filter) and routing thr pipe internally right to the Safari snorkel top with it protruding just out of the end.

Cant see any real issues with doing this, with it out the end of the snorkel it should not see any negative pressure from the induction.

Any thoughts/opinions?

Cheers
Steve 02' 110 TD5 Double Cab Rebuild Thread
Post #946797 23rd Mar 2022 7:59pm
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geobloke



Member Since: 06 Nov 2012
Location: Nottinghamshire
Posts: 4410

United Kingdom 
As long as the breather pipe goes all the way to the top of the snorkel and the pass through gland is watertight then it will be just fine.

A long time ago folks used to run the breather to the RAI pipe, in to it via a rubber grommet and then up to the snorkel top.
Post #946800 23rd Mar 2022 8:09pm
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geobloke



Member Since: 06 Nov 2012
Location: Nottinghamshire
Posts: 4410

United Kingdom 
Just remembered that the MOD had their breathers up in to the snorkel top from the outside, so running the breather up the inside and just to the outside of the snorkel top will work. If it is good for the MOD then... Thumbs Up

Last edited by geobloke on 25th Mar 2022 11:30am. Edited 1 time in total
Post #946802 23rd Mar 2022 8:16pm
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rallysteve



Member Since: 10 Feb 2014
Location: Cumbria
Posts: 2237

United Kingdom 2002 Defender 110 Td5 DCPU Keswick Green
Spot on cheers, was just what I was thinking Thumbs Up 02' 110 TD5 Double Cab Rebuild Thread
Post #946974 25th Mar 2022 10:22am
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westie_



Member Since: 06 Apr 2021
Location: Warwickshire
Posts: 17

United Kingdom 
If the snorkel is water tight, which it hopefully is, is there any reason to run them up all the way to the top? If the connection between the breather and the snorkel is watertight everything should be goo without the extended hoses no? 110 Td5 Van
Post #947056 25th Mar 2022 11:23pm
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landy andy



Member Since: 15 Feb 2009
Location: Ware, Herts
Posts: 5724

2006 Defender 110 Td5 USW Zermatt Silver
Because if you don’t run them to “fresh air” there will suction on the hose, then causing a vacuum in the axles/boxes. Either this may cause to suck the oil into air intake system or just promote water ingress into the components when wading. Some vehicles do the opposite and slightly pressurise them to stop ingress.
Post #947063 26th Mar 2022 5:34am
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Ianh



Member Since: 17 Sep 2018
Location: Essex
Posts: 2027

United Kingdom 
How much space would all the breathers take up if run inside a RAI ? Just thinking you will be restricting airflow, however on a standard map that may not have an impact but worth calculating the percentage of reduced airflow you are going to get beforehand.
Post #947078 26th Mar 2022 9:41am
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blackwolf



Member Since: 03 Nov 2009
Location: South West England
Posts: 17432

United Kingdom 2007 Defender 110 Puma 2.4 DCPU Stornoway Grey
landy andy wrote:
Because if you don’t run them to “fresh air” there will suction on the hose, then causing a vacuum in the axles/boxes. Either this may cause to suck the oil into air intake system or just promote water ingress into the components when wading. Some vehicles do the opposite and slightly pressurise them to stop ingress.


Whilst it is undoubtedly true that there will under most conditions be a partial vacuum (i.e., a lowering of pressure with respect to atmospheric) in the RAI pipework, I cannot myself see that there is any chance of oil being drawn from the axle to intake as long as the vehicle remains the right way up. I also doubt that the partial vacuum would be enough to draw air or water past the axle seals into the axle, although the PV will depend air velocity in the RAI which itself is proportional to the bore of the RAI. Something like the classic plastic Mantec RAI will be at a lower pressure than something like the huge Nak RAI since the air velocity for similar engine conditions will be higher since the RAI is much more restrictive.

It would be interesting if someone was sufficiently intrigued to connect a manometer to the RAI to determine the internal pressure with the engine running at different load and boost conditions.

You could design the entry of the breather into the RAI pipe to use the velocity of the air-flow to create a positive pressure in the axle breathers, but this would lessen the free-flow characteristics of the RAI.

Bottom line, will you come to grief if you connect your breathers into the RAI? I think it is highly unlikely but it is possible under some circumstances, and if you're going to the trouble of extending them all anyway, why not run them to atmosphere at the top of the RAI by extending them and extra three feet or so (90cm for the youngsters).

Personally I certainly wouldn't bother to try to run them up the inside of the RAI pipe to the top, it is a lot more hassle than running them up the outside, it will restrict slightly the bore of the RAI, it will create an unnecessary hole in the RAI with the potential for leaking, all just to save having a small pipe attached to the outside of a larger pipe.
Post #947081 26th Mar 2022 10:16am
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geobloke



Member Since: 06 Nov 2012
Location: Nottinghamshire
Posts: 4410

United Kingdom 
Just a thought Shocked I know I know it happens from time to time... Can't be helped... Rolling Eyes

If you have a steel bodied RAI with steel baking plate, Mantec/PandP/Naka-style... Then it would not be a difficult thing to modify the system by adding a small bore steel pipe to the back of the main RAI pipe. Tacked in place so it is a tight tidy fit. Then run to the top of the RAI (terminating in either a downward facing open end or a rain-proof vent) and through the backing plate via a hollow bolt. Attach the single breather pipe from the manifold to the hollow bolt. Bob's your uncle a tidy method of getting the breathers to the top of the RAI and no risk of sucking the oil out of your axles.

If I may say so myself... Its a good idea Smile I may even do it on MIffy Rolling Eyes Thumbs Up
Post #947105 26th Mar 2022 2:14pm
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