Dawes valve question

phum · **Posted:** Mon Oct 29, 2018 9:02 pm

hello all,
I read on another site about fitting a Dawes Valve to a late model Liberty.
Anybody here have any info. on this?
Is it an advantage or a sales pitch?
Thanks Peter

WWDiesel · **Posted:** Mon Oct 29, 2018 9:19 pm

Why waste your money and limit boost with such a device? :shock:

Max Boost levels can be controlled by tunes. (reflashing the ECM)

flash7210 · **Posted:** Tue Oct 30, 2018 10:18 am

What is a Dawes valve and why would you need one?

WWDiesel · **Posted:** Tue Oct 30, 2018 10:46 am

flash7210 wrote:

What is a Dawes valve and why would you need one?

It is a boost limiting device for variable vane turbos controlled by vacuum.
Google it. :google:

I can see absolutely no need for it on a Libby CRD.

flash7210 · **Posted:** Tue Oct 30, 2018 11:00 am

I did google it and it didn’t really answer the “why” part.
Seems to me that under certain conditions it could set a underboost code.

Again, why would you want this?

phum · **Posted:** Thu Nov 01, 2018 7:01 pm

Do our motors never go into overboost situations , if they do where do they bleed off to?

mass-hole · **Posted:** Thu Nov 01, 2018 9:40 pm

phum wrote:

Do our motors never go into overboost situations , if they do where do they bleed off to?

If they do then there is most likely something wrong. The ecu controls boost pretty well.

WWDiesel · **Posted:** Thu Nov 01, 2018 9:42 pm

phum wrote:

Do our motors never go into overboost situations , if they do where do they bleed off to?

IF for some reason the boost were to get to high and boost pressure exceeds the upper readable range of the MAP sensor, the ECM will place the engine in a "limp" mode.
And it works as a protection when a sensor gets too far out of range in the fueling circuit.

phum · **Posted:** Thu Nov 01, 2018 9:44 pm

No more silly questions, all well for now

Dawes valve question

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