I'll preface this by saying that I haven't tested all conditions with the microsquirt and as I type this I've got about 5 minutes of long term testing. For anyone who doesn't know what microsquirt is, it's a miniaturized version of the opensource Megasquirt II unit. It's advantages for our application are the dual VR inputs and low cost. More information can be found at
www.microsquirt.info
Going to stand alone engine management will give you the ability to tune ignition timing and fueling. You can also ditch the air flow meter and really free up the intake. I expect power gains but that will be based on the skill of the person doing the tuning.
What you will need:
1 944
1 Microsquirt $400
2 Ballast resistors (7.5 ohm, 25 watt aluminum housed) $20
1 GM MAP sensor (I used 3bar and in retrospect should have gone smaller) $64
1 Intake Air Temp sensor $17
1 Laptop with a DB9 connector
1 Basemap (Free!)
Assorted electrical tools, heatshrink tubing, etc.
What I recommend:
Wideband O2 sensor (highly recommended)
Timing light
Scrap DME
I have used a spare DME box provided by a friendly pelicanite to use as a swappable ECU. I can switch back in my motronic just by switching the dme wiring harness back over.
This is how the box looks with the cover off:
The wires you need to connect are as follows:
Power:
DME pins 18 and 35 to AMPseal Pin 1 (red wire)
Grounds:
DME pins 16,17,19 to AMPseal 21,22,23 (Black wires)
VR sensor-
DMe pins 25,8 to AMPseal pin 33 (silver coax shield)
VR input 1+ (speed sensor)
DME pin 27 to AMPseal Pin 32 (silver coax center (White wire))
VR input 2+ (reference sensor)
DME pin 26 to AMPseal pin 4 (brown/white stripe)
VR Sensor shields:
DME pins 5,23 to DME pin 28 (ground)
Fuel Pump:
DME pin 20 to AMPseal pin 8 (purple)
Injectors:
DME pins 14,15 to Ballast resistor to AMPseal Pins 9,10 (blue and green)
Ignition:
DME Pin 1 to AMPseal Pins 11 AND 12 (White/red, White)
Coolant Temp:
DME pin 13 to AMPseal Pin 25 (Yellow)
Intake air temp and MAP sensor wire according to microsquirt.info instructions. Use 5v vref and sensor ground from AMPseal.
O2 sensor
AMPseal pin 34 to either external WBO2 or to DME pin 24
Tach (I don't have this working yet)
DME pin 21 to AMPseal Pin 35
Optional wiring
Air Flow Meter (for map/maf blending)
DME Pin 9 to AMPseal Pin 29
Idle valve (I don't have this figured out yet, but it idles fine without it)
DME pin 33 or 34 to AMPseal pin 7 (green)
Boot loader
AMPseal Pin 15 (purple) to grounding switch
Throttle position sensor (you can run without this on the n/a so this is turbo wiring)
KLR pin 21 to AMPseal pin 28 (5v vref gray wire)
KLR pin 22 to AMPseal pin 27 (sensor wire)
If you do it like me, it will look like this when wired in:
You will need to upload a basemap and here is the current version that I have (right click save as):
http://www.ualberta.ca/~jlewicke/porsche944running.msq
Of course this is an install at your own risk and I don't guarantee this will work for every setup. Proceed with caution and check things as you go. Read lots about megasquirt and microsquirt. I am happy to help people with problems they may have and answer questions, so ask away!
The project thread is located here to see the trials and tribulations I had along the way.
944 MicroSquirt Plug and Play Project
JustinL