Thread: Snorkel/RAI or ****

Originally Posted by tact

The standard position on a Defender is also the spot where the water level or wash, post bow-wave, is at its lowest while you maintain forward motion.

I have hung my head out driver window and watched as that water wash curled under, and as it got deeper, halfway up the stock air intake grille. (Dont have and don't want a snorkel or RAI)

Wasn't at all worried about water half way up the grille. (Ever sucked on a straw where the open end is totally submerged in your drink, but it has a tiny hole in it?)

Really Neil, I don't want to harp but if you of all people don't need a water proof snorkel, they need never have been invented.

Originally Posted by tact

The standard position on a Defender is also the spot where the water level or wash, post bow-wave, is at its lowest while you maintain forward motion.

I have hung my head out driver window and watched as that water wash curled under, and as it got deeper, halfway up the stock air intake grille. (Dont have and don't want a snorkel or RAI)

Wasn't at all worried about water half way up the grille. (Ever sucked on a straw where the open end is totally submerged in your drink, but it has a tiny hole in it?)

Your vehicle, your call...

Hope you never stop mid crossing

Originally Posted by cuppabillytea

Really Neil, I don't want to harp but if you of all people don't need a water proof snorkel, they need never have been invented.

Heh! my point exactly.

(And all that in an electrickified TDCi)

Originally Posted by Tombie

Your vehicle, your call...

Hope you never stop mid crossing

And you, dear sir, again reaffirm the great respect I have for your opinions. A respect born of reading so many posts you've made - all good!

You are absolutely right in that stopping in water up to, or over the lower edge of, the stock air intake - may well have been fiercely detrimental to vehicle life.

And that detriment in stopping would be coming from a couple of directions:
- inside the vehicle filling up with water (consequences!)
- water hitting turbo
- engine ingesting water
- bearings, boxes, diffs etc...

Even without stopping there were consequences. (Cost of proactive change to all oils in all boxes/diffs. Evidence of water around wheel bearings so stripped and regressed etc). All of which I was happy to bear.

Just to defuse the minds of the unimaginative (or overly imaginative) let me hasten to write:
- I don't advocate others taking on such deep water activities, with or without a snorkel (but I will argue passionately against those who cast nasturtiums on the TDCi capability to even go near water, as I have gotten out of my cyber sofa and done it)

- heck, I don't intend to go so deep ever again. I don't need a snorkel to give me a safety net if my plan is to never go more than 500mm in future (as I know via my own experimentation that at that depth (500mm) I know have another 400mm safety net available already). Std disclaimer that walking a crossing, or following others' path, to avoid surprises, do fully apply.

- even when I did go so deep it was not without certain confidence and calculation.
1. I knew my path well, smooth flat hard bottom with no undulations or surprise holes/dips. I knew where it would shallow up again. Very well.
2. I knew the lay of the dirty air intake ducting and that it is riddled with gaps and completely unsealed.
3. I counted on the holey straw analogy working for me.

This last point (2- dirty air intake duct) deserves some treatment in detail - I experimented a lot.

Here is a dare for anyone with stock dirty air intake ducting: Take a sheet of 80gsm photocopy paper and place it over the air intake grille. The amount of "suck" (non-SI unit) at idle won't even hold the paper against the grill. It will fall to your feet. You need to dial up about 2500rpm before there is enough suck to hold a few grams of paper against the air intake grille. (Of course it is "push" not "suck" that holds the paper to the grille eventually - the push of atmospheric pressure trying to get air into the duct opening blocked by the paper)

Here is another dare. Go for a drive. Keep it in 1st gear. Reach out the driver window and slap that sheet of paper on the grille (not grill - that's for the lobster later) and run up and down the rev range. Dare you to notice any reduction in engine performance due to the obstruction.

That there are multiple air paths into the dirty air duct before (and where) it enters the bottom of the air cleaner, and that many of these air paths are higher than the actual external intake grille, and that the physics of the straw with a hole in it are real, and the path to the turbo intake is via the top of the air filter box lid, which in itself is not sealed well - all says that it doesn't matter a toss if the if the air intake grille were to take a brief full face slap of water.

I bet on all that. Because I wanted to see. Could have turned to custard. Didn't. Now I know I am ok to run without a snorkel with a self imposed 500-600mm wading limit as that comes with a 300-400mm safety net (which does not remove the need to take the usual precautions to avoid surprises)

(Of course if I were planning a trip to the tip of Cape York - where plenty of YouTube vids show the need for much deeper than 500mm deep wading.. Everything changes.)

Ditto Tombie. and fair call Neil. I guess I could be a bit of a nervous Nelly.

Originally Posted by Tombie

Stick your head out the window next time you have the chance...

Almost no dust in that area...

However, if it was at the front - even a gentle splash of liquid could be terminal

As usual, thanks for your input.
I would not argue that in general, the intake position is fine and might well be better than a front mounted intake for both dust and water. I made mention of slow dusty conditions which from my experience found the intake position wanting. Your experience might well be different which is how most things are in life I suppose.

Getting back to the question of whether a RAI is useful or not, my opinion was that they are good cheap insurance on a Defender if the vehicle is used in the bush given that the Defender snorkel by Safari is on the lower cost end of their entire 4x4 range.

To illustrate the improvement with a well sealed RAI, I just took the ram head off my Safari snorkel, started my 2.2 engine at idle then blanked off the intake. The engine dropped revs immediately and I noticed the snorkel body began collapsing inwards where it covers the intake, so I had to stop. Happy days! I fitted my own RAI as others I have had fitted by shops rarely bothered sealing the ducting properly.

Everyone will have their opinions and experiences but it gives me more confidence knowing that I have sealed all the ducting and drains well enough that I can induce enough suction through good sealing to start to collapse the ducting. It also means that the air box top clamping on the air filter element is currently in good enough condition at present. So I now have better sealed ducting than standard factory ducting to roof level. I am happy that my Defender is far less likely to suck in dust and water than standard.

Originally Posted by cuppabillytea

Ditto Tombie. and fair call Neil. I guess I could be a bit of a nervous Nelly.

I wouldn't say that, a nervous Nelly, cuppabillytea. Just do make sure it is really sealed up properly and then it's there always should you need it.

(BTW - Hope you didn't think I was thinking of you when I mentioned "... the unimaginative (or overly imaginative)" in the long note I wrote. Certainly NOT intended. )

As for me - the day may well come when I am stuck the wrong side of a river that wasn't so flooded when I went in - and can't get out. Maybe I'll wish I had fitted a snorkel on that day. Or not.

never know when you'll hit a pothole that you didnt see and its deeper than the rest.
snorkel is cheap insurance