Here's what is needed:
APC Control unit, and plug for
control unit and some custom made brackets (See pictures)
Wire connectors for control unit, Saab
Part number: 91 20 957 (You'll need 9 of them, get some extras just in case)
APC Solenoid
and bracket. (and wire connector)
Knock Sensor,
and shielded wire for knock sensor, you will need a long length, so take some time
and remove the entire wire in tact from a wrecked car.
Pressure
Transducer
Wiring
diagram for the APC System
Miscellaneous lengths of wire.
A hand full of wire ties and lengths of
vinyl wire loom covering to make it really neat.
Tee fitting
for solenoid dump line. (fabricated and added into the hose going to PCV fitting in turbo
intake hose)
Straight vacuum fitting to replace the tee
fitting to the overboost switch. Save the tee fitting.
Misc. lengths of vacuum hose.
Several insulated female spade connectors.
Heavy duty oil resistant hose for APC
solenoid plumbing and appropriate hose clamps.
Where to get the parts:
All of the parts for this system can be bought used from a wrecking yard. If you can find a U-Pull-It yard that doesn't know what the parts are you may get everything very cheap. Anywhere from $25.00 to $200.00 seems to be the going rate depending on the wrecking yard. The cars you want to take the system from are:
Saab 900 turbos, 1986 to 1993 (They had APC
before '86 but it is a different system and not recommended).**
The control unit on the 900's is located
in the forward inner fender well on the left side, it is either black or red (If you get a
red one, BONUS! That's the hot rod one). See picture of
control unit on the main home page.
The APC solenoid is mounted behind the
radiator above the plumbing for the turbo. It should be easily visible.
The pressure transducer is located under
the driver side knee panel to the left of the clutch and brake pedals. It's not
visible readily and you really have to dig to get at it. Remove the knee pad if possible.
The knock sensor is mounted on the block
under the intake manifold between cylinders 2 and 3.
Saab 9000 turbos, 1986 to 1989**
The control unit on the 9000's is located
in several different places depending on the year of the car; under the knee panel, under
the false cowl panel (in front of the windshield), or possibly under the driver's seat. It
will be either black or red (If you get a red one, BONUS! That's the hot rod one). See control unit picture on main home page.
The APC solenoid is mounted behind the
radiator in plain sight.
The pressure transducer is located under
the driver side knee panel on top of a metal tray that will need to be pulled down, it's
hard to get at and will require some digging, it is to the left of the brake and clutch
pedals. It is not readily visible.
The knock sensor is mounted on the block
under the intake manifold between cylinders 2 and 3.
Picture of part locations for 9000 models..
**Important Special notes:
You do not want the
control unit from a pre-86 900. You can tell the pre-86 control unit because it is
gray or black and only has 14 pins in the connector. It is located under the back
seat. Leave this control unit sitting in the puddle of water that it is soaking in
and find yourself the later one. The early control units were problematic and most
of them are dead by now. The newer control units have far superior knock detection
circuitry. Here's a picture of the early unit so
you'll know what to avoid.
Non turbo Saabs have
an EZK ignition computer that looks EXACTLY like an APC computer! Make sure it's a turbo
car. Later 9000's have a box labeled DI/APC, you don't want that it has nothing to
do with the system you're looking for.
Be sure to get the shielded lead for the
knock sensor, you will have to spend some time cutting the wiring loom open, but it is
necessary to use a shielded lead. I would also recommend leaving the connector on the
knock sensor end since this will make it less work when hooking the system up.
Also be sure to get the plug for the APC
control unit since you will need it also.
While you're in there, get the overboost
switch if you like. It's highly adjustable and is located near the pressure
transducer on the same vacuum line.
