Wastegate mod.....

[Simon Quested]

Hi Robert and All

Snip
> The greater the spring pressure the greater the amount of
> boost required to unseat the valve and vent a portion of the exhaust,
> thereby reducing the pressure driving the turbo?

yep
 
> As I understand it, when the force of the exhaust on the waste gate valve
> plus the force of the boost pressure on the diaphragm equals the spring
> force, there will be no seat pressure and a slight amount of exhaust will
> leak past the waste gate valve. Additional boost pressure will compress the
> spring lifting the valve off its seat. This will vent some of the exhaust
> gases, reducing the amount of exhaust available to drive the turbo.

You are on the money.....depending on the wastegate I've been told that some start 
to open at half of the boost set point, this means that the turbo isn't getting all of the 
exhaust gas and so it spools up slower. The control unit minimizes this by using a 
boost solenoid to keep the wastegate fully closed until just before max boost. 

Cheers

Simon
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  Simon Quested (E-mail questeds at lincoln.ac.nz)
  Computer Technician, Silicon Graphics & Windows NT Support
  Centre for Computing and Biometrics
  LINCOLN UNIVERSITY OF NEW ZEALAND
  Phone (64)(03) 3252811 Ext. 8087
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http://www.lincoln.ac.nz/ccb/techs/simon/default.htm
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Albert Einstein: "Only two things are infinite, the universe and
human stupidity, and I'm not sure about the former."
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