Defender 200 tdi Dump Valve - Whats the point?

Isn't it supposed to allow oil and general shit to escape the intake area?

`Mark

This would probably be a better explanation than mine, but then it isnt a true dump valve!?

If this is all its for I suspect it can definately be sealed up.

Jon

So Jon was, like

Depends on the set-up on your vehicle, but on my 90 n/a it was vital. The intake on the wingtop lets in water to the air intake, and the dump valve allows it to drain out. Whenever I'd got it really muddy and the dump valve got sealed by the crud, the water would accumulate and next time you turned on the heater all the windows misted over. Quick proggle of the rubber valve and you could see forward again. Quite important, really.

It's not a "dump valve" in the chavved-up nova sense, it's a water release valve that is there to allow water to escape from the air intake system. I think there's another one somewhere around the air filter too.

Some people remove them when they fit a snorkel on the basis that with a snorkel you're much less likely to get water, twigs and small animals in the air intake system so the release valve's not needed so much, and if anything the water release valve is more likely to let water in than the snorkel is.

Seal it up, or leave it open, makes on odds really provided that you're happy that the air intake system is reasonably water and creature proof.

Some snorkels, e.g. the Safari one, have a box at the bottom of the snorkel that extends below the line of the pipe leading to the air filter, this box catches twigs and other crap that makes it through the snorkel mouth. If yours has one of these, then even more reason not to bother with the release valve.

For the record, the kind of dump valve I think you are talking about (the one that kevs fit to their cars, and yes I've got one on one of my cars) fits between the turbo and the inlet manifold, not the air intake and the turbo. Unless you're not thinking about what I'm thinking about.

so.... can you explain what the dump valves do on KEVS car, and should i fit one? S`pose not, as my names Andy, im 38 and drive a Landy, but i could start a craze, all the Kevs switching to Landys, souping them up and hanging around car parks in town centres. Low profile GRIZZLEY CLAWS and all.

andy

ps... im serious about the dump valve explanation......

On a petrol engine the inlet tract is blocked by the throttle butterfly when the throttle is closed - this causes back pressure to the turbo and thus stops it spinning. In the case of changing up a gear this leads to a shot flat spot of no boost as the turbo spools up when you open the throttle again in the higher gear. The blow-off valve (dump valve) releases this excess pressure allowing the turbo to keep spinning on an upchange thus allowing full boost immediately without waiting for the turbo to spool up again. It's only of any real benefit on large turbos that suffer excessive lag.

erm... the wingtop air intake only feeds the heater, not the engine...

Regards. Mark.

On or around Sat, 16 Apr 2005 09:23:08 +0100, MVP enlightened us thusly:

exactly, if it gets water in it, it'll feed wet air into your demister.

confused the crap outa me, I think 'dump valve' and I think about the thingy in the manifold or a turbo engine rather than the little rubber wossit in the bottom of the air filter box. Is there such a valve in the heater box? spose there must be considering the intake is open-upwards allowing rain straight in. I'll piss-off now and do something useful....

Regards. Mark.

On or around Sat, 16 Apr 2005 10:20:41 +0100, MVP enlightened us thusly:

there is indeed.

I've been doing something useful:

Would it be picky of me to suggest that something is missing on the style front?

On or around Sat, 16 Apr 2005 11:44:51 +0100, Dougal enlightened us thusly:

bah. form follows function, innit. besides, I've painted the chassis, now. I might even paint the wheel and the top...

Well any turbo suffers lag, some greater than others, so it's of benefit on smaller turbos too with relatively little lag. It's also beneficial for the turbo reliability too as the backpressure from the inlet manifold puts stress on the turbo that just doesn't need to be there.

Lots of cars have dump valves as shipped from the factory, but factory-fitted ones are recirculating ones that blow the excess air back in to the intake system on the other side of the turbo, so doing away with that woosh sound so beloved of the kevs.

So MVP was, like

That's the valve I thought he meant. The only dump valves I know are on heater intakes, but then I've only ever had n/a diesels. Should have read the post more carefully.

Hehe, a dump valve on a Defender diesel! Most unusual.

Indeed, although it has to be said that when I replaced the turbo in the plastic rocket it only cost me 300 notes for a recon job, and that was a full replacement as mine was so old and badly looked after, it would have been less if the car's previous owners had looked after it more.

Ok,

So in another context (not the rubber thingy) what would a dump valve be?

Thick 90 owner in Norfolk....

Regards

Richard

Waste gate on the turbo I'd guess.

P.

yea, that's what I understood to be a 'dump valve'.

Regards. Mark.