Thread: New ZS!
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Old 11-10-09, 09:00 AM   #15
will-w
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Join Date: Dec 2008
Location: Ashford, Kent
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Quote:
Originally Posted by David View Post
A friend of mine tells me it'll hapily run 25PSI, yes 20 is peak. It has got a boost guage. Is it normal for a DERV whilst driving to be always boosting something? it never goes into vac or is that normal?
If you run 25psi, then you'll blow it.. On standard internals anything over 20psi is very frowned upon, anything over this and you'll be asking for either HGF or a blown turbo and/or damaged oil seals. You'll also be seriously shortening the life span of the engine/drivetrain.

Due to the size of the turbo on the diesel (it is TINY - the turbo on my Smart Roadster was bigger!), it will always show some boost... While doing a steady 60mph you should see between 5psi and 8psi, depending on the type of road you're on... Using the engine to slow you down should use none.

As for the minimal vac, yes that is perfectly normal.. The diesel has no dump valve to release the pressure (like a petrol), as our engines need the boost to function properly. The wasegate will release excess pressure, but you'll never really hear it.

Hope that helps
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Last edited by will-w; 11-10-09 at 09:02 AM.
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