I guess my previous posting concerning the use of pressure switches wsas a
little too casual and it caused confusion.
I hope this explains it a little better.
There are 2 applications where pressure switches will help the turbo owner
increase power and stay safe. Firstly, when the computer has a chip or zener
in it which effectively removes the overboost protection. In this case,
wiring a pressure switch which is closed until the pressure rises to a
dangerous level, in series with the fuel pump relay will protect the engine
from overboost by cutting the fuel pump.
The second case is when our intrepid pilot wants more power with minimum
cost. In this case, wire a pressure switch which is open until the boost
pressure rises to 5-6 PSI, from the fuel pump to ground. This will switch
the fuel pump on and hold it on when there is boost pressure and will
override the boost cut.
Ideally both switches should be used in the second application.
If you are having problems getting switches, you know who has them but they
are not easy to plumb in as the connectors are 1/8" BSP threads. We have no
adaptors etc to help, but the parts are there if you need them. Mail me
directly for more details.