Adding MBC but have a question...
11-06-2007, 10:10 PM
#1
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Adding MBC but have a question...
hi, I have a mbc that I'ld like to install, but im not sure I see the point. How can the spring thats in the wastegate be overridden. If the spring gives in at .8bar of boost, how does the mbc prevent the wastegate from opening until it's preset pressure is reached?
thanks guys!
thanks guys!
11-06-2007, 10:54 PM
#2
Rennlist Member
MBC- best to have a dual port wastegate for this to work correctly
anyway- your line to the wg pulls a vac. on the line- essentially holding the wg closed- as well as the spring- keeping the exhaust aimed at the turbo and spooling it up. When boost starts to build, the vac in the lines turns to positive pressure, pushing on the wastegate instead of pulling- and when it has enough pressure to overcome the spring it pushes it open. Now if you put a controller in the line from the intake to the WG- it works the same. BUT when the positive pressure starts to build the MBC does one of two things dependent on the type of WG you have and the type of MBC you have as the dual port see pressure above and below the diaphram.
The regulator type of MBC used w/ dual port wastegates slows the flow of the air reaching the WG, and therefore it takes greater pressure from the intake to open the WG- raising your boost pressures.
the type of MBC used for a single port (stock) WG has a check valve and it will build so much pressure and then the check valve will close letting the turbo build pressure and open the WG spring on its own w/o fluttering open and closed- at least this is how i understand this to work such as the Lindsey Boost enhancer.
ANYways its a way to trick the WG into thinking there is less boost when there is more.
anyway- your line to the wg pulls a vac. on the line- essentially holding the wg closed- as well as the spring- keeping the exhaust aimed at the turbo and spooling it up. When boost starts to build, the vac in the lines turns to positive pressure, pushing on the wastegate instead of pulling- and when it has enough pressure to overcome the spring it pushes it open. Now if you put a controller in the line from the intake to the WG- it works the same. BUT when the positive pressure starts to build the MBC does one of two things dependent on the type of WG you have and the type of MBC you have as the dual port see pressure above and below the diaphram.
The regulator type of MBC used w/ dual port wastegates slows the flow of the air reaching the WG, and therefore it takes greater pressure from the intake to open the WG- raising your boost pressures.
the type of MBC used for a single port (stock) WG has a check valve and it will build so much pressure and then the check valve will close letting the turbo build pressure and open the WG spring on its own w/o fluttering open and closed- at least this is how i understand this to work such as the Lindsey Boost enhancer.
ANYways its a way to trick the WG into thinking there is less boost when there is more.