Electrical questions
+ Reply to Thread
Results 1 to 5 of 5

This is a discussion on Electrical questions within the General Maintenance, Troubleshooting & Accidents. forums, part of the Tech & Modifying & General Repairs category; I've put an ls1 in an 02 wrx and had some questions. I've noticed the thicker wires that go to ...

  1. #1
    Registered User 02scoobywrx's Avatar
    Join Date
    Aug 2009

    Electrical questions

    I've put an ls1 in an 02 wrx and had some questions. I've noticed the thicker wires that go to the alternator dont go directly to the battery, they run into the main fuse box. Should I hook that up to the ls1's alternator instead of just running a wire from the alt. to the battery?

    Wheres the best place to tap into for an ignition hot wire? Its just going to be a signal wire to turn on the relays for the ls1's harness. It has to have power while the starter is turning too because its powering the ls1's ecu and harness. And whats the best way to tap it so its reliable?

    And lastly, what does the main relay power? It wouldn't de-energize and was keeping the fuel pump relay energized so I unplugged it (main relay) and now the fuel pump relay works correctly. I can't seem to find anything that is affected by the missing relay.
    Last edited by 02scoobywrx; 07-01-2012 at 07:50 PM.

  2. Remove Advertisements

  3. #2
    Registered User teflon_jones's Avatar
    Join Date
    Apr 2007
    8000' up in Colorado
    You posted another thread about wiring for your LS1 swap and didn't really get any responses, and I'm afraid that's what you're looking at again. It's such a rare thing done that you need to find somebody that's done it before in order to get your questions answered. Anything anybody here tells you I wouldn't trust unless they've actually done it. I know a lot about cars, wiring, engines, and all sorts of things but I still wouldn't try and give you advice on such a swap.

    On a side note, a couple of questions if you'd answer them:
    1. Why did you decide to do this swap? Why not go with an STI short block or just build out a regular WRX block with a big turbo or something like that?
    2. Do you know anyone that's done this swap, whether personally or somebody you've met or even just read about on a forum or other internet site?
    3. Do you have any pictures of the progress so far?
    4. What's involved in doing this? Are you running a GM tranny with the LS1? What's the running gear on the car (axles, hubs, suspension, etc)?
    5. Besides the engine, what else are you changing?
    6. What's the goal for this car? Is it going to be a drag car, daily driver, weekend toy, etc?
    7. What do you think the final cost of this swap will be?
    8. Is this going to be AWD or RWD?

    Thanks in advance for whatever info you're willing to share!
    Past Subies - '11 STI Limited stage 1+ and '04 STi stage 2+
    '13 Wrangler Rubicon - custom front bumper w/12k lb winch & off-road lights, skid plates, diff guards, etc.
    '04 Porsche 911 Turbo GT2 clone 600 HP/TQ
    '77 F-150 heavily modded for off-roading

  4. #3
    Registered User 02scoobywrx's Avatar
    Join Date
    Aug 2009
    Well, do you know anything about how the charging system on the wrx works? I could atleast get a better understanding and possibly figure it out. Also, could you tell me what the main relay powers? Any info about these systems would help me figure it out.

    The reason I went with this swap is that it should be a more reliable engine/trans that has more power than the ej stock. This is my 3rd wrx and I wanted something different.
    There's a guy that did this swap a couple years ago, and I saw it on a forum, and I wanted to do the swap ever since.
    I actually posted a build thread earlier today after 3 months into the build. 02 Subaru Wrx Ls1 build - LS1TECH
    I picked up a complete ls1 with the t56 6 speed. I had to build a custom crossmember to mount the engine and steering rack to. The engine never would have sat low enough with the factory crossmember in place. I had a driveshaft made to connect the t56 to the stock diff. However, the stock diff isn't strong enough to handle the torque the ls1 puts out, so i'll have to upgrade one day. I haven't decided which diff i'll use.
    As of right now, im leaving the engine stock (i dont know if anythings already been done to it though). I'm wiring it so that the stock gauges work. I will have a seperate oil pressure and coolant temp gauge though.
    I plan on this being my daily driver once I get everything sorted and working good. And i'm hoping to take it to tracks like little talladaga or road atlanta, but that might be awhile.
    Honestly, I dont want to know how much i've spent all together on this swap, but im sure its atleast 7k between the engine and all the parts i've bought. I got the car really cheap so it wont be too bad.
    And it will be rwd. I dont think awd could possibly be done. GM has an awd system, but I dont think there is enough room to make it work in the wrx.

  5. #4
    Moderator T0rque's Avatar
    Join Date
    Dec 2004
    Medford, Oregon
    I Support ClubWRX
    The main relay in many cars powers all MAIN things. Fuel delivery, ignition system. Personally for something like this you need to buy atleast the electrical portion of the oem service manual.

    Lead Wrench @ WTF Tuning, LLC

  6. #5
    Registered User 02scoobywrx's Avatar
    Join Date
    Aug 2009
    I have access to all the oem manuals, but it will take time to look through it and figure it out since i'm not familiar at all with the diagrams.

+ Reply to Thread

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself. We strongly suggest that you stay away from using aol, yahoo, msn, and hotmail accounts. Sometimes the mail server blocks the emails from our server. As a result you will not receive any notifications including the confirmation email.

Please select your insurance company (Optional)


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Posting Permissions

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts