re- boost controller options- autoworlds article

[Robert Deis]

On Sat, 5 Oct 2002, Alan Pritchard wrote:

> So he was wondering why sometimes he was gettin 12.5 psi, rather than the
> set 11 psi. So here goes....
> pressure regulator set at 11 psi, therefore while the wastegate is still
> opening to its full amount the turbo is still spooling!!!!!!

My experience here is with 1 port WGAs, I don't know quire how the 2-port
variety compares.  That said:

Using this sort of system, there are a number of things to tune to get it
to work right.  First is that the regulator valve needs to open quickly.
A slow acting valve will produce exactly the results you're describing--
1- Set pressure is reached
2- Regulator valve opens
3- As pressure makes its way to the WGA, boost spikes over set pressure
4- Pressure reaches WGA and level settles back in to set pressure.

I think the volume of the hose between the regulator and the WGA plays
here, too-- bigger hose volume takes longer to pressurize-- but I'm not
positive of how significant that is yet. If it matters, smaller diameter
and shorter hose length are both important.

Also the size of the bleed hole used to let the pressure escape when you
go off boost is important- this bleed hole actually functions as a second
boost control adjustment and bleeder type systems tend to be very
suceptible to weather conditions, so you want the hole just big enough to
serve its purpose.

--
------------------------------------------------------------------------------
  Rob Deis                  "Let the people know beforehand what the law
  MiB3347                      is and what they are to expect."
  rdeis at io.com                              -- 18th Congress, Rec. 75