ECU Location

[Buzz Skyline]

I'm laying out my wiring harness now, and I'm thinking of putting the ECU (the manual calls it an ECM I think) under the passenger side dash. It looks to me like it would reduce the amount of rewiring I'd have to do as well as keeping the unit dry and cool.

Where are the rest of you (the ones using donor harnesses, anyway) locating your ECU? Is there a good reason to go with the instructions in the manual?

Thanks,

Buzz

[D Clary]

I mounted mine on my rear firewall. Most of the wiring goes from engine to ecu so mounting it clo33859ser to the engine will reduce the run of wiring.

[Buzz Skyline]

That looks like an aftermarket ECU. Are you rewiring the whole car yourself?

That's a very tidy looking build, BTW.

[svanlare]

I added a firewall between the engine and the gas tank and intend to mount the ECU there.

[D Clary]

I got the ecu from Wayne @VCP. It is a race car and I'm not using enough of the Subie wiring to warrant messing with it. So I am wiring from scratch, though I am still finding ways to procrastinate.

[Bob_n_Cincy]

I mounted mine in the center of the engine -cockpit firewall. (2004 DBW Turbo)
This is my wire count with a complete diet.
ECU to engine drivers side 39
ECU to engine passinger side 23
ECU to transmission 5
ECU to Dash 28 (DBW and ODBii under dash)

I like keeping the important signal wires (ecu to engine) as short as possible.
Bob

[iWire]

In our setup we mount it direct to the backside of the firewall. I would suggest as svanlare said to put in an extra firewall or build a box for it to help keep moisture to a minimum since no matter where you mount it back there it's open at least a little bit to the elements.

http://i34.photobucket.com/albums/d123/keenerrs/iWire%20R%20Spec%20Harness/P4170230_zpsf362a7ca.jpg

[svanlare]

You need to check out Bob's thread, it is what I'm aspiring to with my build.

[Bob_n_Cincy]

You need to check out Bob's thread, it is what I'm aspiring to with my build.

Thanks Svanlare, I'll take that as a compliment. ECU is in post 95 and 120.

http://thefactoryfiveforum.com/showthread.php?12534-MRG-MotorSports-818S-Build/page3

[Jaime]

I put mine pretty much where Bob_n_Cincy put his, but on the passenger side panel. The wires from the ECU to the driver's side of the engine are already six feet too long anyways.

[Rasmus]

Thanks Svanlare, I'll take that as a compliment. ECU is in post 95 and 120.

http://thefactoryfiveforum.com/showthread.php?12534-MRG-MotorSports-818S-Build/page3

Nice install. Using that as inspiration #1.

[Bob_n_Cincy]

Nice install. Using that as inspiration #1.
You would be proud of me. Took about 20 KILOGRAMS out of the car.
Bob

[Rasmus]

You would be proud of me. Took about 20 KILOGRAMS out of the car.
Bob

Now I'm impressed. Proper work there. May the lightweight fairy bless you with many high G turns and braking so late you scare yourself.

[FFRSpec72]

You would be proud of me. Took about 20 KILOGRAMS out of the car.
Bob

I added 102 lbs with the anti-intrusion side and floor panels

[Jaime]

I might have Bob beat:

http://i871.photobucket.com/albums/ab273/jaime398/818%20Build/20140721_215801_zpsx8vevcx7.jpg

http://i871.photobucket.com/albums/ab273/jaime398/818%20Build/20140721_215738_zpsiuyrnbhf.jpg

http://i871.photobucket.com/albums/ab273/jaime398/818%20Build/20140803_115052_zpshv6qosea.jpg

I literally don't have an inch of wire that I don't need.

[Kyle@AJW]

We mounted ours on the pass side on the front fire wall. It is more added wire length to mount it anywhere in the front. I felt for this being a street car it seemed to be a better location to keep out of the elements.

http://i202.photobucket.com/albums/aa254/streetsideracing/Mobile%20Uploads/2014-09/0DDBA95B-CB27-4DBD-BDBF-D58ABC31EFA0_zps79ndihwo.jpg (http://s202.photobucket.com/user/streetsideracing/media/Mobile%20Uploads/2014-09/0DDBA95B-CB27-4DBD-BDBF-D58ABC31EFA0_zps79ndihwo.jpg.html)

[Buzz Skyline]

That's what I was thinking, Kyle. If you use the stock harness and mount the ECU in back, most of the wires go up to the front of the car and back to the ECU. So you can put the ECU up front without extending anything extra except the MAF wires, I believe. It also seems to make it a little easier to get all the dash and steering column connectors hooked up with minimal wire lengthening.

The only question is whether the MAF sensor will behave differently with another 5 feet of wire attached. I don't think so. The ECU, I believe, only uses the MAF info for low throttle (closed loop) driving. So it's not like you have to worry about delays introduced by extra wire or anything.

In any case, I'm probably going to put the ECU in a watertight box. After all, mine will be open top for a long time (until I save up for a top) and there's always the risk of getting caught in a storm.

[tmoretta]

Do you have a pic. of the anti-intrusion side panels?

[FFRSpec72]

Do you have a pic. of the anti-intrusion side panels?

See my build thread http://thefactoryfiveforum.com/showthread.php?12205-FFRSpec72-818R-Build-Seattle-WA

[Jaime]

most of the wires go up to the front of the car and back to the ECU.
I disagree. If you look at this picture, you can clearly see the ECU bundle tee off to one bundle going to the front and one going to the left side of the engine.

http://i871.photobucket.com/albums/ab273/jaime398/818%20Build/20140721_215801_zpsx8vevcx7.jpg

The bundle going to the front is slightly larger, but it includes all the power wires that don't go to the ECU. I also have a lot of stuff in that front bundle that many people won't have, like cruise control, AWIC pump, and heated seats. Also, the bundle going to the right side of the engine would add to the number that have to go back.

As for protection from the elements, if you add a rear firewall, then the ECU is completely enclosed.

[Buzz Skyline]

Wow, Jaime, that is amazing. Did you build a harness from scratch?


I might have Bob beat:

[Jaime]

That's the factory harness; stripped and dieted. I either shortened or lengthened pretty much every wire. I did build the fuse box from scratch.

http://i871.photobucket.com/albums/ab273/jaime398/818%20Build/20140802_214835_zpsdhi3gibw.jpg

[Bob_n_Cincy]

I might have Bob beat:
I literally don't have an inch of wire that I don't need.

Great job Jamie, :cool:
Sometime I think it is ashame to cover up all that work. But at least we will know it there.

In the tunnel I have control wires (same) fuel lines (2) brake lines (6) #6 power feed to front fuse box.
I still need to add 4 wires for rear lights.
Did you redo your schematics?
Bob
33928

[Buzz Skyline]

That's the factory harness; stripped and dieted. I either shortened or lengthened pretty much every wire. I did build the fuse box from scratch.

How long did it take you?

I minimally dieted my harness and crammed it all in. It's ugly and heavy, but I'm under some pressure to get the thing driving ASAP. I'm planning on buying another harness and making something pretty over the winter months, so it would be great to get an estimate of the hours it might take to shoot for something like yours (although, I'd probably budget twice as much time to account for relative skill levels).

[Jaime]

About 80 hours over five weeks. I'm pretty good at soldering, so that helped me. The biggest single chunk of time was stripping the Subaru harness. It was dirty work that I didn't enjoy.

I also spent a lot of time shopping. It takes a lot of time to find connectors that you can buy in low volume without paying through the nose. Weatherpacks are great for high-ish current connections, but they are big, ugly, and only available in low pin counts. I ended up using a lot of Molex MX150 series connectors.

I'm not sure how to add up the time I spent dreaming about the wiring section of the factory service manual - I think the standard Inception rule is that every hour dreaming is worth 20 waking hours. Maybe it's the other way around.

[Buzz Skyline]

We mounted ours on the pass side on the front fire wall. It is more added wire length to mount it anywhere in the front. I felt for this being a street car it seemed to be a better location to keep out of the elements.

I tried several arrangements, including back and front locations for the ECU. I ended up going with the front passenger firewall too. I have to extend wires for the connectors that go to to the passenger side of the motor, but I would have had to extend them nearly as much with the ECU in the back because of the way they're routed in the stock harness. Jaime's wiring is much better, of course, but I did next to nothing to my harness except fold it in a couple places.

[Quiny]

I did a pretty straightforward wire diet. I do agree that all the sheathing must be removed from the stock harness. Once you untangle everything you will find that 1 or 2 wires prevent straightening out the harnesses. Lengthen or shorten them and it becomes much more manageable. I have the wiring installed and working and did not need to use any of the FFR supplied wire. I would say that I reduced the wiring by 1/3. Once it was simplified it seemed like the best spot for the ECU was behind the passenger seat on the firewall like many have said. You end up with very little wire running through the tunnel.
34234342353423634237

[DMC7492]

Jaime, awesome job on the ECU! What are these fuse blocks?
34246

I am in the same boat as you on the weather pack connectors for the engine I am using the Deutsch DT 16 connectors from wirecare.com
Check this stuff out, http://www.wirecare.com/products.asp?prodline=dpp

I ordered last week Thursday and received them five days later very fast!

[Jaime]

I love Deutsch stuff, but they aren't cheap. These guys (http://www.molex.com/molex/products/family?key=mx150_sealed_connector_system&channel=PRODUCTS&chanName=family&pageTitle=Introduction) are much cheaper and are available up to 20 pins. I got mine at WayTek (http://www.waytekwire.com).

The fuse blocks are Cooper Bussman #15310 (http://www.waytekwire.com/item/46348/60-POSITION-NON-BUSSED-RTMR/). Here's what they look like loaded:

http://i871.photobucket.com/albums/ab273/jaime398/818%20Build/20140802_220649_zpsnm5hst2h.jpg

[DMC7492]

Jaime that is a very well laid out panel, is this just for the engine management? Or do all the relays include the lighting,fuel pump, fans and other accessories?

[Jaime]

That's almost everything. I have a small strip of relays under the hood for the horn and headlights.

[Scargo]

With my R, if I'm using something like a Racepak, AIM or similar display, and have a full array of digital gauges, along with data-logging capabilities, would there be any advantage to having the ECU up front? Just thinking that there's a lot of sensor wires that will have to go to the front anyway.
I thought I'd have the battery near the front, but in the cockpit. Do you have to have the main power cut switch in the front dash area? Fuel cell location will be like Plavin's or FFR's.

[KidTurbo]

Scargo, I'm also wiring an AIM setup and considered mounting the ECM up front. However the AIM setups use all their own harness and engine sensor. So that leaves you only requiring the tach, fuel level, VSS and MIL light wires from the ECM. Along with the clutch switch and TPS which will reach easy from the back.

There isn't enough wire length in the factory harness to reach the front kick panel. So I'm going with the rear firewall designs shown above. This leave you only lengthening like 4 or 5 wires vs half the engine harness. I originally had concerns related to water and the ECM, then saw how others have done it. Eased my fears.. I'll post some pics when it's done next week.

[insurance guy]

I mounted mine where side mounted seat belts would go
I have the I wire kit and there was enough wire to mount it no problem493484934949350

[Scargo]

Let me clarify that I essentially have nothing but a DAVCS engine wiring harness. I will be running a DAVCS engine.
I have a master battery power switch required by NASA and SCCA. I have one dual SPA gauge I may use. Other than that it's a blank sheet for me and I only require the bare essentials for a race car. I am considering having a few spare wires in the harness run from front to back in case I want to gather data from other sensors or control more fans, valves, etc. I suspect I want (need?) an aftermarket ECU since I believe I am correct in saying that *the stock ECU does not monitor oil pressure or oil temperature and possibly other important data that a racer like me/we would like to collect*.
*As a side issue, is there any way around this and be able to log this data? I can get an STi ECU for $250 and most aftermarket ones are over $1,000. Can I get empty connectors for a stock ECU that I can load up myself?
How do I collect the other data?
I have so many questions about this aspect of my build. I can do the wiring but I don't know what I need for what I am trying to do. I don't know what is adequate and what can possibly be expanded without starting over.

[JeromeS13]

Glyn,

If you're using an AiM Sport cluster, you can definitely use the OEM ECU. Just get the Subaru plug n play harness, oil pressure sensor, (two temp sensors are included with the Pista), and any other sensor you want to add, in addition to what the OEM ECU will provide already (a lot).

[Sgt.Gator]

Scargo after having a AIM MXL Pista I would not get anything less next time. My next build will be another MXL Pista or the newer MXL2. They both get data from a Subaru ECU CAN connection, then you add in the additional sensors. you want to datalog. I know next time I'm going to include suspension potentiometers, I think they would be invaluable for both aero tuning and analyzing what's really happening thru a corner.
They are expensive though....

[Mitch Wright]

Scargo, I agree with Sgt Gator, I also am using an AIM MXL2, it has a ton of flexability that is hard to beat for the price.

[KidTurbo]

I'll agree with the "hard to beat" on this particular build, and haven't installed it yet.

Where's the preferred spot, in dash or on the column?

[JeromeS13]

I'll agree with the "hard to beat" on this particular build, and haven't installed it yet.

Where's the preferred spot, in dash or on the column?

If you're running an aftermarket, smaller steering wheel, it'll be blocked a little by the top of the steering wheel if you put it where the OEM gauge cluster goes. I would recommend mounting it closer to the wheel, further up the column.

[KidTurbo]

If you're running an aftermarket, smaller steering wheel, it'll be blocked a little by the top of the steering wheel

What I figured after looking at some other race version setups. Was either that, or everyone racing is nearsighted... :rolleyes:

Thanks

-K