| This modification to the MBC is designed to reduce boost
taper at high RPMs. Currently this is a work in progress, I put the tap
after the intercooler on the stem before the bypass valve. While this
eliminates boost taper it creates another problem, pressure spikes. Since
the tap is several feet down the line from the turbo the pressure will
build up over 15 psi which causes fuel cut before the MBC can open the
waste gate. There are two solutions to fix boost spikes. The first one is
to install a pressure relief valve near the throttle body which will vent
pressure over 15 psi to the atmosphere. The second solution is to install
a small spring valve before the MAP sensor to prevent the ECU from
"seeing" the boost spikes. Although the first solution is better I cannot
find a suitable valve for this application, therefore I am going with the
second option. The boost spikes are 17 psi at most and last for less than
a second, so danger to the engine is minimal. |
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