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The MBC+A addresses fundamental flaws in the operation of ball-spring MBCs.






A manual boost controller can often (application specific) be added to a turbo charger installation to replace the OEM controller. This allows for:


  • Higher than stock boost levels and power
  • Faster boost response

Most MBCs are now ball-spring types, as these make the turbo spool up much faster than the older ‘bleeder’ type MBCs. The only downside of the ball-spring types is that they will always create boost pressure overshoots in an application where the turbo spools up very fast. As everyone wants fast boost response, so this is a common problem. And most OEM turbo setups are undersized which spool up very fast with a MBC.



Boost Pressure Overshoots:


  • Often mis-named ‘boost spikes’
  • An intrinsic property of all ball-spring type MBCs.
  • Very common with typical EOM undersized turbo application.

Boost overshoots cause problems. They cause high torque transients that can send a clutch into slip in higher output applications. They also can trigger fuel cuts or other defensive measures in many ECUs. To avoid these, one has to reduce the boost setting. Thus one’s peak sustained boost is reduced by the magnitude of the pressure overshoot. This is a major loss of power. Why does all of this happen?



A ball-spring MBC does not flow until the boost pressure is very close to the boost pressure objective (that is the design objective). If the rate of boost increase is slow, there will be no problems. But if the rate of boost is fast, then the MBC needs to get the wastegate open very fast. But it is too late. The MBC simply cannot get the wastegate actuator flow pressurized and flow stroked fast enough, and there is a pressure overshoot. Lightweight balls and springs will not, can not, eliminate this problem!



A ball-spring MBC simply operates too late to regulate the boost pressure when the rate of boost response is fast. We all want fast boost response. The MBC+A overcomes this fundamental flaw in ball-spring MBCs by directly compensating for what the ball-spring MBC cannot do. The MBC+A applies a regulated pressure to the wastegate actuator as the boost pressure is increasing. This anticipates the actuation of the wastegate actuator (WGA). The anticipator pressure is adjusted to pre-pressurize the WGA. This regulated pressure is not enough to open the WGA. Now when the ball-spring MBC starts to flow, its flow can get to the business of stroking the WGA open immediately without delay.



Many MBC’s cannot be fed pressure from the intake manifold or TB, as this introduces a time delay that makes pressure overshoots much worse. These applications typically get pressure from the turbo compressor hose barb. Also, these applications suffer from boost pressures that droop drastically at high RPMs. The pressure is been regulated at the turbo compressor, not the intake manifold. The pressure at the manifold drops as the higher air flow rates creates pressure drops across the intercooler and piping. The MBC+A allows you to pressurize the MBC from the TB or intake manifold *. Boost pressure now only drops off when the turbo is up against its own flow limitations.





MBC+A benefits:


  • No pressure overshoots; even in cold weather
  • Higher boost levels when pressure overshoots otherwise force lower settings
  • No boost pressure overshoot induced clutch slip
  • No controller induced boost pressure droop when fed from the TB
  • No boost pressure induced transient AF lean mixtures

* The anticipator is always pressurized from the turbo compressor hose barb.
 

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There is a FREQUENTLY ASKED QUESTIONS thread in the NG900 workshop.


What is this MBC+A thing I hear so much about?
LINK 1
 

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I wonder how many times you will have to do that Spatl. Maybe you should just leave a phone number.
 

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your a nice guy for taking the time lol
 
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