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.