BoostControl (2005-05-15 23:15:31)

Overview of boostcontrol

Typical Pneumatic connections

For both installs, activating the solenoid raises resulting boost. We need to control PWM-duty to get to boost target. Raised duty = raised pressure.

An install where raised solenoid duty is needed to (open wastegate and) lower boost is just dangerous. Firmware supports it, of course, but avoid it.


Boost control system layout:

Primary system for internal wastgate:

Primary system for external wastgate:

Improved spoolup and range for external wastegate:

The systems are sequenced, first pressure is applied to the top chamber but if that is not enough (remember EBP pushing on the wastegate valve) the boost control working on the lower chamber will start to bleed off boost. In addition to this the system acting on the bottom chamber is always bleeding off as much boost as possible until the system is getting over the adjustable 'spoolup' threshold.

Note that the atmosphere connection can be replaced with a vacuum connection. A vacuum reservoir will NOT work, it has to be a fairly high capacity vacuum pump. (If a zero break pressure check valve is found and used (never seen one) to atmosphere a vaccum reservoir can be used.)

-Jörgen


See also