Quote:
Originally Posted by Clarkson
This seems legit to me:
http://www.cobbforums.com/forums/sho...w-to-interpret
I think of it this way.
Maximum Boost achievable = Fixed WG spring pressure + WGDC allowed pressure
From my experiments with the WGDC table.
40 in the ATR table equates to approx 100% observed/logged WGDC.
Once you hit 100% WGDC, that is all she has got. |
Hold on there. That's for a Mazda Speed 3, not a BMW. The BMW boost control is
backwards to typical boost control systems. The boost pressure does not directly control the wastegate actuators. The wastegates rest fully open, i.e. no boost. The vacuum pump sucks down those two canisters. The ECU switches the solenoids to open, allowing the vacuum to reach the WGAs. The vacuum starts to suck the wastegates shut. Then the ECU regulates the solenoids via duty cycle to maintain proper boost pressure developed, which is read after the intercooler but before the throttle. (The sensor in the manifold is used as a redundancy check.)
Therefore, WGDC means wastegate is more closed, which results in higher boost pressure. The numbers are the same - higher WGDC means more boost, but the rest of the logic in the other forum post does not apply to these cars.