GM BCS Install

Discussion in 'Tech, Tips, Newb Info' started by Shibbs, Oct 21, 2007.

  1. Shibbs
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    Shibbs The Daywalker

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    I got my GM Booost Control Solenoid installed. 06-07 WRX guys, there's not a whole lot of increase, but it does peak the torque a little lower. According to the logs, my peak torque went from 3100-3200 RPM down to 2800 RPM. (for refrence, I did have a stage 1 map on my car) Hearing all the clicking that little guy makes is pretty cool too. :cool:

    Parts needed:
    1. GM BCS - GM PN: 1997152
    2. GM Pigtail - GM PN: 12102747
    3. about 6 feet of silicone vacuum tubing (good for heat, and stretches well)
    4. Wire cutter and crimper
    5. Knife
    6. 10mm socket and wrench
    7. Lighter/heat source for shrinking connectors included with #2.


    Oh yeah, just to make sure everyone knows:

    YOU WILL NEED A TUNE AFTER INSTALLING THIS. The car can be driven, just stay out of the boost!!



    Find the stock BCS, and cut the wires, leaving enough on the stock connector to re-wire it back in, if you ever decide to do so. This is especially true if you're planning on leaving both connectors on the harness. The wires are covered by a black sleeve, use the knife to cut this off and toss it in the garbage, as it isn't recyclable.

    FYI: There is a little positive sign on the GM BCS, and it is important which wire goes where. Yellow wire goes to the little '+' sign on the BCS (#1) plug. Obviously, the black goes to the negative. THE CONNECTOR (#2) IS NOT LABELED POSITIVE OR NEGATIVE.

    If you're using the GM harness kit, it comes with heat-shrinkable connectors with hot glue inside them. They work amazingly, I've never had a problem with them, and I've probably used thousands. Just get a good crimper. The only problem is, these are designed for the size wire that GM uses. Fine and dandy for the Subaru positive (yellow) wire, but the negative (black) is EXTREMELY TINY. I got around this by stripping a good amount of wire off the negative and wrapping it back down on top of the insulated part of the wire:
    [​IMG]
    Then insert that in the connector and crimp away. Then shrink/glue with a lighter or small torch.

    To use both wiring connectors, you may need bigger shrink connectors. Try this at your own risk.

    After that, connect your vaccuum hoses the way they are illustrated in the diagram, and it should be ready to get tuned!

    1. Shiny nipple all by itself on the GM BCS goes to the TURBO OUTLET
    2. Nipple that comes with the little foam "filter" on it goes to the intake post MAF, or vents to atmosphere. (Remove filter to expose nipple if plumbing back into the intake, leave on if venting to atmosphere)
    3. Last one only has one other place to go. Wastegate.




    [​IMG]

    This clip is a bit of a pain to get to, both on and off. (Outlet of turbo)
    [​IMG]

    Finished setup. FYI, you can splice in the GM BCS Connector to leave both sensor ends, but then you'd have to worry about keeping the unused connector clip covered/taped up. I chose to not do this, obviously.
    [​IMG]
     
  2. Shibbs
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    Shibbs The Daywalker

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    Alright, I got a bit of bad news today.

    THE GM BCS IS DISCONTINUED.




    After this, one would either need to tear one off a Cyclone or Typhoon (yea right) to get one.
     
  3. idget
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    idget Want to pokéman? PM ShortytheFirefighter Staff Member

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    Just installed one on an 03 and decided to take pics of the 03 and pics of mine to show some mounting options.

    02-03 wrx:

    Make sure you pull the 3 metal sleeves out of the rubber mounting bushings. It reduces the clicking/ticking quite a bit.

    [​IMG]

    [​IMG]

    06-07 wrx/sti:

    You can mount it vertically off of the middle mount for a more stealth install. The wires are tucked back under the black cover (where the stock bcs mounts). If mounting vertically, I would suggest angling it slightly so condensation doesn't accumulate directly on the harness.

    [​IMG]

    closer view (you can just see the top of the pigtail harness (blue):

    [​IMG]
     

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