re- boost controller options- autoworlds article

Jim Green jeg1976 at
Sat Oct 5 12:33:28 EDT 2002

--- Alan Pritchard <apritchard at> wrote:
> So he was wondering why sometimes he was gettin 12.5
> psi, rather than the
> set 11 psi. So here goes....
> Boost is rising but the wastegate is not opening,
> when 10 psi is set in the
> wastegate line the pop off valve opens and allows
> the wastegate to start
> opening but the wastegate can not open as fast as
> possible because of the
> pressure regulator set at 11 psi, therefore while
> the wastegate is still
> opening to its full amount the turbo is still

My thoughts exactly, I was sitting here thinking how
to put that into words.  I think the only safe place
for the pressure regulator is the upper chamber.  I
wouldn't want anything fooling the wastegate into
thinking there is less manifold pressure than there
really is at high boost.  Granted the pressure relief
valve does some fooling, but not when it's important.
Like when you "cane" it! -Autospeed

Just having the pressure relief valve in teh lower WG
nose set to your specified boost level would work if
you didn't mind a brief overboost period while the
wastegate is opening.  Some people like that kind of

So here's my future system:

- 1.8 bar Charlie spring good for 15 psi cranked down

- Pressure relief valve and small air bleed (to
  relieve pressure when under vacuum) in lower
  WG hose to help spoolup.

- Electronic solenoid that opens and adds pressure
  via. a regulator hooked to top WG port to bring
  boost up to 22 psi.  This will only be activated
  when the water injection is enabled, or until I get
  a header, then it's 22 psi all the time!


Jim Green
'89 90tq 034EFI, Haltech IG5

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