Megasquirt

     Megasquirt by itself is a standalone fuel management system.  It is a "build it yourself" kit that you solder together, and wire your own sensors.  I'm not going to lie, it takes some time to install, and tune, but it is quite worth it in the end.  Using a system like this is far better than using an adjustable fuel pressure regulator, with this system, you fine tune your fuel curve to match your specific engine.  When you install the system, you will disconnect any part of the motronic engine management that controls fuel, and must re-wire the injector harness.  You also get to remove the dreaded flapper style AFM!!! This dramatically increases throttle response, and removes the bottleneck.

    -Sensors:  Sensors for the system include, coolant temperature sensor, intake air temperature sensor, throttle position sensor, o2 sensor, and the supplied MAP sensor.  My coolant temperature sensor is in a tapped tube, attached to the coolant hose that goes from the thermostat housing to the water pump.  My intake air temperature sensor is located on the reverse side of the blow-off valve pipe. 

For the throttle position sensor, you have a few options.  You need to buy a potentiometer style TPS, not a WOT switch type that comes stock on the e30.  I bought my TPS from a 95 Volvo 850.  I had to make an adapter plate to mount to the holes, but it works.  Now for your stock WOT switch.  You need to retain it to keep the stock timing curve (unless you are using MSnEDIS or MSnS).  I mounted 2 limit switches near the top of my throttle body, so when I am at idle, it sends the signal to the idle part of the WOT switch.  I disconnected the WOT part of the WOT switch so it does not advance my timing anymore under WOT, this helps to prevent detonation.

    -Injectors:  With Megasquirt, the injector size is not restricted like Motronic.  I run 32lb/hr injectors, and actually need higher.  Wiring the injectors does not take too long.  You simply take apart the injector wire harness.  Disconnect the wires that connect to motronic.  Motronic works in two banks of three, cylinders 1,5,3; and 2,4,6.  For Megasquirt to work correctly you need to wire it to be 1,2,3; and 4,5,6.  Thi is because the engine fires 1,5,3,6,2,4.  Doing it this way, the two banks will fire alternately.  In the pictures, the orange wire is the 12v power, which connects to one pin of each injector. Then the black goes to 1,2,3 and red goes to 4,5,6.  I retained the stock injector harness connector so it still connects to the stock coolant temperature sensors on the thermostat housing.

    -For the oxygen sensor, I used the stock one, and spliced it so it runs to the stock ECU as well as megasquirt.

    -When you assemble Megasquirt, it tells you to attach the MAP sensor to the main PCB.  I didn't like this setup for a few reasons. One, its kind of a long stretch, two, the MAP sensor should be close to the top of your intake system.  This keeps oils, and fumes from settling in the map sensor.  To avoid this, I bought a small project box from Radio Shack, and put the MAP sensor on a small PCB, and connected the wires back to the Megasquirt board.

    -Though not necessary, I opted to buy the relay board for megasquirt. This helps wire the whole system, and keeps it looking clean.  To do this, I had to make a wire harness that connects the main PCB to the relay board.  I used 2 25pin parallel connectors, and wire.  You must make sure you connect it correctly, so that it is a straight through system.

    -The relay board also must be connected to the fuel pump.  I did this by splicing into the fuel pump relay harness.  It is located on the intake side of your engine bay, next to the strut tower.  The fuel pump relay on my car was one the left.  And the wire that connected to the pump is the thick red one with a white stripe.  You can see the wire with the splicer and the black wire (from megasquirt) connected to it.

    -Tuning Megasquirt is probably the hardest part, unless you have a wideband o2 sensor.  I would HIGHLY suggest you buy one, it will save you a LOT of money in the long run.  I spent about $900 dyno tuning my car using their WBo2 sensor.  You also need to get a laptop to tune the system.

    -I am planning on running Megasquirt n' EDIS ignition system in the near future, so I can have full control of my engine.  I will get rid of all of the stock motronic engine management system.  I will be able to retard timing a little more at high rpm high boost, to keep from detonating.  The new features of Megsquirt also have more features than I thought ever would. You can find more information on new features and EDIS here

    -To find out my Megasquirt settings and fuel maps, click here