BoostCreep

I had a lot of trouble finding accurate and detailed information on wiring and other issues when I decided to install a boost gauge in my 2009 STi, so I decided to do a write-up myself. I was amazed at how many people used terms like "the boost thingie" and "the wire goes to the fuse in the fuse box" in other write-ups, so I did my best to be a lot more accurate. I hope it helps someone in need.

I added more information below each picture in case I thought something should be clarified, so please read both.


INSIDE THE CAR - WIRING AND GAUGE INSTALLATION



Pull off the lower dash cover. It just has clips holding it on.




These are the only two screws that hold the lower dash to rest of the dash. Remove these and the rest of the lower dash can be pulled off.




Lower dash pulled away from the upper, left of the steering wheel.




Lower dash pulled away from the upper, right side of the steering wheel.




There are 4 clips holding the instrument hood to the dash. The entire hood pulls off as one whole unit, but the hard part is getting a good grip. To get better finger placement, I pulled the top of the inner part of the hood away, which revealed a little lip that I could use to pull the hood off. Caution: Do not pull heavily on the inner piece because it is bolted to the rest of the hood at the bottom and could break if you pull on it too hard. Just pull on the top part of the instrument hood itself. Also be careful not to lose the 4 yellow clips that hold the hood to the dash. They come out easily and can get lost.




There are two screws for the instrument cluster. One is circled in the pic and the other is to its left.




Pop the plug off the cluster on the right side.




I ran the wires for the gauge through the upper middle hole above the gauge cluster.




Gauge vacuum tube hanging under the dash.




Tap into the purple wire on the dimmer switch for headlight power. This wire is only powered when the headlights or parking lights are turned on.




Close-up of where I spliced into the purple wire. For the ProSport gauge, the ORANGE wire splices into this purple wire. The wire is black in my picture because I used black wire to extend the wires coming out of the back of the gauge.




For ACC power, use the brown and white striped wire on the top connector above the fuse box. This wire is powered when the key is in the "ACC" position only. With the ProSport gauge, you connect BOTH the RED and WHITE wires to this wire.

The green and white striped wire on the same connector is on all the time, meaning it is powered even when the car is off. I found that out the hard way. (Do not use that wire.)


UNDER THE HOOD - VACUUM TUBES AND TMIC REMOVAL.



Remove the circled bolt.




Remove the circled bolt.




Remove the circled bolts, including the clamp that holds the silicone coupler to the TMIC from the throttle body. There are also 4 bolts under the top side of the intercooler. They are a pain to get to, but much easier than trying to deal with the coupler on the turbo itself. All of the bolts are either 10mm or 12mm with the exception of the clamp on the coupler, which is 8mm.







Pop the plug off the firewall. A good idea is to put a hole in the middle of this plug to use as a grommet once you run the vacuum tube from inside the car.




Use a long screwdriver to push a hole through the insulation inside the hole, then push the coat hanger through that hole until it comes out under the dash in the driver's side footwell. Make sure to angle it down towards the driver side like in the picture.




The hanger after being fished through the firewall.




Tape the vacuum tube (or wires if you are installing an electrical gauge) to the coat hanger very securely. I put the hanger inside the tube and taped around the connection.




Pull the coat hanger through the hole and the tube should come with. This is tricky and may take a few tries. Make sure the hole is large enough for the tube to fit.




Remove and cut the BOV (BPV) vacuum tube with sharp scissors or a razor blade. You want a clean cut so the tube sits flush with the vacuum T.



Vacuum T installed. Use small zip ties to secure the connections and avoid blowing off the tubes under boost.




Vacuum T installed. Reattach the factory tube to the BOV nipple.




I ran the gauge's vacuum tube around the side of the TMIC to avoid crushing underneath it. Make sure it has plenty of slack to avoid pulling while driving.




To make the hole in the instrument hood for the tube and wires, I melted the plastic of the hood with a soldering iron. Very quick and easy.




Gauges with the headlights off (daytime mode).




Gauges with the headlights on (nighttime mode.)



So there it is. Hope it helps. Please let me know if there are any questions, but it is quite straightforward. I didn't go into mounting the gauge or reassembling the interior as I figured that is simple enough.

 

lethaldose

nice write up thanks

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spending money I don't have, to buy parts I don't need, to impress people I don't know

20wrx09

you could have routed the tubing threw the fender and there is a grommet in the fender well. i found this way easier to do instead of removing the intercooler

kenscholl

Very thorough writeup...good job! thanks!

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Politicians, like diapers, have to be changed frequently - and for the very same reason.

bad mutha

doing my boost gauge today,clean install!