Subaru EZ30r into 914

[Mayne]

Hi everyone, new here so I thought I'd introduce my project. I have a 75 Porsche 914 that will be receiving an EZ30R swap, along with Subaru 5MT. I have a lot of mechanical experience with cars, but setting up a custom ECU is going to be new territory for me, so pardon the barrage of (stupid?) questions!

I have the motor and tranny now so I'm getting ready to pull the trigger on an ECU. I'm thinking of going with a Link G4X AtomX. The engine will remain N/A and totally stock other than custom exhaust. There are a few items that make me hesitate until I can confirm that this is the right choice. First, the AtomX says it supports up to 4 cylinders direct spark (as in, coil-on-plug?). Is this right? It seems like people are using it for more cylinders that that. Also, the EZ30R is DBW, and in looking at the Link ECU comparison chart, it seems like the AtomX doesn't support electronic throttle. And then finally, it's listed as having 1 channel Can. Is that adequate to deal with the Canbus of the EZ30R? 

Thanks for any input!

[Adamw]

The Atom cant do E-throttle directly, the Xtreme or Fury are the only wire-in ECU's we have that do E-throttle.  The Storm & Monsoon can do E-throttle with an external module, but the Monsoon doesnt really have enough IO to do much else and the Storm with external module will end up costing about the same as an Xtreme. 

So If you wanted to use one of the low cost ECU's the best option would probably be to convert to a cable operated throttle body. - You would need to consider options for adding an idle control valve as the E-throttle would have been used for that originally.

The Atom and Monsoon have 4 injector drives and 4 Ignition drives, so for a 6 cyl, you would need to wire the coils in pairs for wasted spark ignition, and the injectors would be wired in pairs or 3's for multi-point group or possibly semi-sequential mode if the firing order allows it.

The most important consideration is how much IO (inputs/outputs) you need.  Write down a list of everything the ecu needs to measure and control and check the ecu has enough.

Outputs Example:

1. Fuel pump
2. Fan
3. Tacho
4. AVLS solenoids

If E-throttle you will also need these further outputs:

1. Throttle motor +
2. Throttle motor -
3. E-throttle relay control

 

Inputs Example:

AN Temp

1. Coolant temp
2. Air temp

AN Volt:

1. TPS
2. MAP sensor
3. Wideband?

If you go E-throttle you will need an extra 3 AN Volt inputs:

1. TPS sub
2. Pedal main
3. Pedal sub.

Any other sensor for engine protection or just logging/info such as fuel pressure or oil pressure will also need further AN Volt inputs.  

  

[Mayne]

Okay, thanks for the reply. A couple of other questions: If I were to go with the Xtreme, are there EZ30R base maps included? Also, I would need a "A" and "B" looms correct? 

 

[Adamw]

I dont have a EZ30 map for a G4X, but I can knock up something that will get you running without too much work.  

For the B loom question it will depend on how much you can do yourself and what tools and supplies you have on hand.  You probably wont end up with a lot connected to the B plug - maybe 6-8 of the 34 wires.  In this sort of situation I generally wouldnt buy the B loom, just the bare plug and add only the wires I need.  But if you need to buy a crimp tool and several rolls of different colour decent wire then it would probably just be cheaper to buy the B loom.