What exactly is a cutout raiser? How does it work?
The factory stock computers use a MAP sensor that can't
"see" over 1 Bar,
which is one "atmosphere", which is 14.7 psi.
Therefore the computer has no way to see boost over 14.7
psi. It has no way
to feed you the necessary fuel for more than that. So the factory shuts
off the
injectors if you try to boost "too high". Some older cars shut off
at around 11 psi;
most cars shut off at 14.7 psi.
If you want to boost over 14.7 psi, you need to keep the
computer from
knowing that you have reached 14.7 psi.
The MAP tells the computer how much boost you're running
by receiving
pressure at the MAP sensor through a vacuum line and converting it
to
voltage. As the boost goes up the voltage goes up. Somewhere near 5
volts the computer shuts you off, or "cuts out" the engine.
So you can raise or eliminate the cut out point (usually
14.7 psi) by
EITHER keeping the pressure at the MAP sensor under 14.7 psi, OR by
keeping the voltage well under 5 volts.
Diodes keep the voltage in the 4's, lower than the
cut out voltage,
so there's no cut out. The MAP bleeds and G valve cut out raisers keep
the air pressure lower in the MAP line, which in turn keeps the voltage
to the computer lower than the cut out voltage.