I mentioned this document I found somewhere on the internet in my "Calling
all "What's that thingy?" experts ..." thread. Many thanks to whoever
produced the information and I apologise for not being able to credit the
author. If anyone reading this knows who produced the information, please
let me know and I will add the authors name and web location for if I
re-post the information.

The exact readings for the various APC boxes are nicely detailed for anyone
who want to reproduce the exact setup of whichever box.

Cheers all,

Paul

The document:

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Stock APC* -*Simple boost increase adjustment.

Locate and open APC unit in inner fender.
Locate pot screws "P", "F" and "K".
Turn "P" screw clockwise to +/-* 25,000 ohms.
Turn "F" screw clockwise to +/-* 400 ohms.
DO NOT touch the "K" SCREW (knock sensor sensitivity).


Stock APC box numbers and resistor settings.

75-66-599 160 hp*R42=5.1k ohms*R138=26.7k ohms "P"=12.1k ohms "F"=98 ohms
75-24-127 175 hp*R42=5.1k ohms R138=26.7k ohms*"P"=12.4k ohms*"F"=201 ohms
43-93-971 185 hp*R42= 510 ohms*R138=30.8k ohms*"P"=23.2k ohms*"F"=295 ohms

*
Modifying the APC by replacing resistors.
*
If you want even more you can also modify the electronics of the APC. You
need a multi-meter, solder, screwdrivers, and appropriate 1/4 watt
resistors. I am listing below*suggestions of performance increase
modifications.

Please understand that even though there is good feedback on these methods
they are still*"try at your own risk modifications".


Red Box APC

R42=500 ohms
R138=31k ohms
"P"=23.2 ohms
"F"=295 ohms


For best performance it is a MUST*that base boost be approx 5 to 6 psi. To
increase base boost the waste-gate shaft is shortened.

The "Fuel Cut Out Switch" must also be adjusted for higher boost levels. The
switch is set to cut the fuel pump at 14.7 psi. By turning the center screw
clockwise approx 2 turns will raise the cutout limit to around 20 psi.

It is recommended that a FPR 2.8 or higher be used.***

0280160255 is 2.5 bar.
0280160264 is 2.8 bar.
0280160256 is 3.0 bar.
028016000 is 3.3 bar.

The "P" & "F" potentiometers need to be tweaked upwards and the "K" pot,
which controls knock sensitivity, is to be left as is.* All the articles
that I have read, advise to turn the "F" a lot the "P" a little and so on.
You can remove the APC cover and adjust the "P" and "F" pots then take a
test drive and re adjust until you are happy with the results.