All turbochargers can over boost but boost is regulated by the waste gate.
The ability to over boost is needed to ensure quick spin-up and response and
as you mentioned in your post, to provide full rated boost at higher
elevations.

The turbo Mercedes diesels I used to own were set to 1 BAR with a mechanical
waste gate and if you knew what you were doing you could easily get 1.5 BAR
of boost. 1 BAR is 1 atmosphere or about 14.5 PSI. Highway fuel economy
actually increased a little with the higher boost setting.

The Jetta, being a 02, may have computer controlled boost. If it does then
you my be able to find a aftermarket controller to over-ride the factory
curve. The 1989 Lebaron Coupe GTC I used to own was computer limited to 12
PSI boost but a "off road only" performance computer swap set the boost to
15 PSI.

Thanks, Tom Hargrave
www.stir-plate.com
www.towercooler.com
www.kegkits.com

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Mike Miller
Sent: Wednesday, July 13, 2011 1:06 AM
To: vanagon@gerry.vanagon.com
Subject: AAZ overboost

Does anyone know if the stock AAZ turbo provides any over boost? I had
an 02 Jetta TDI that I was told would provide full boost up to 5000
feet because of that over boost capability.

Mike
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