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Just another lowly GM6 build

12458 Views 157 Replies 20 Participants Last post by  Combat Chuck
Hi everyone, just wanted to share a project I’ve been working on for a very long time. I know it's nowhere near as fancy as 90% of the builds here but maybe someone might appreciate it :)

I was a Subaru fan from as long as I can remember. A friend of mine took me for a spin in his Group N WRX in the early 2000’s and I was instantly hooked. He let me pull it up the starting line for rallycrosses, even though I had problems with the stiff 6 puck clutch, as a 12 year old I knew I had to have a fire-breathing Subaru of my own. GC’s always appealed to me more than the GD chassis, no doubt due to it’s rally heritage.

In about 2005, my father managed to find an immaculate ’95 GM6 in Florida for less than 500$. We drove it back the same week, thrilled to start our first ever build. Even with the piddly stock 1.8 and ancient tires the lightweight chassis had me excited. We didn’t have much of a budget to complete a full build immediately so things took quite some time. Sourcing a EJ255 from a wrecked LGT through Copart was the official start of the project. I still remember the day we started salvaging parts and my father standing over me, teaching me everything I needed to know about wrenching. We painstakingly took apart the donor car, making note of every bolt and hose location. A couple busted knuckles and lots of “I told you so’s” from him and we managed to get everything lined up and positioned in the engine bay. Wiring was another obstacle. iWire wasn’t even on the map when we sat down and spent dozens of frustrating hours going through schematics of the LGT harness and the 04 STi ECU we were going to run our motor with. I learned to solder, terminate wiring, and most importantly patience during that time.

Trying to fire it up for the first time was a disappointment, an errant wire spliced in the wrong place prevented the ECU from getting power. Countless hours later we got it running with an open downpipe and bunch of angry neighbors. As a young teen that was by far the proudest moment of my life, a memory I’ll never forget. With smiles all around we took it for a spin, my childhood memories finally coming true. Even though it had a stock tune I felt I could take on anything on the road and win.

After a few months of driving, the stock motor dropped a valve, splitting a piston in half and scoring the cylinder walls. Frustratingly we pulled the motor, took it apart and started calling shops for options on how to properly build it up again.

Unfortunately school and other priorities got in the way of our build, and our Subie sat undisturbed in a garage for the better part of a decade. A year ago I saved up enough to fully build a longblock, and this time it was my turn teaching my dad how to gap rings, assemble heads, and time the motor. It took us a while but we got it together and running last summer. A few hiccups along the way and we went on our first test drive in the new motor on a hot July day, no AC of course. I still remember him yelling at me for throwing on a silly burble tune that sounded like an M240 as we drove down residential neighborhoods. Unfortunately, the drive was cut short by a total loss of power, SBF-5 was blowing. Swapping them out didn’t help so we pushed the car 2 miles home cursing the whole time. We spent days trying to figure out what was going on, the heat didn’t help at all so decided to wait until the cooler fall months to take out the wiring harness and try to find out what was going on.

My father died of a massive heart attack on September 11 of last year, a few days before we were set to pull the dashboard and harness.

I couldn’t bear to even look in the garage for months after without completely breaking down. I’d never again pass him sockets and wrenches as he racheted underneath the car for those lower downpipe bolts or have him hold up the fifth iteration of an exhaust we were trying to make fit. Everything related to the car reminded me of him, how I could always ask him for advice at a moment's notice, knowing that if I screwed anything up he'd always have my back. Now I was on my own, it was all up to me to keep going. This might sound silly but until this this day I can still hear his voice every time I work on our projects, as if he never left my side.

Earlier this year I got it running again. It was something silly, just like he said it would be. The main relay was faulty and only one contact was clicking, providing power to interior electrical systems but not to the ECU. A stupid 10-dollar part prevented us from enjoying our newly built motor together for months, something we will never do together again. That first fire-up was bittersweet; I was elated that it fired up on the first turn of the starter, but he wasn’t there to hear the gravelly rumble of the 280 cams.

Since then I threw on parts we didn’t get to last year. I was dreading pulling rear knuckles due to the rear lateral arm bolt, but of course my father predicted this and slathered it in anti-seize over 10 years ago so they slipped right out to my surprise. Everything I touched reminded me of something he’d teach me, from spraying some WD40 on exhaust hangers to get them in easily to not bolting down one side the intake manifold down fully before hand tightening the other side so everything lines up.

I don’t know what my future plans are with the car, it could use a good coat of paint after 26 years and maybe some flares, but I’m sure as hell not selling it for as long as I’m still around.

Miss ya Daddy.

Here's some shots from last year, ill throw up some new ones soon.



EJ57 case halves
Turbo Tuff I-Beams
CP pistons
ARP 625 studs
D25 Heads
Ferrea Beehive Springs
BC Stainless Valves
BC Stage 3 280 Cams
ID1000 Top Feed Injectors
V1 Perrin Fuel Rails w/ OEM FPR
Radium fuel rails/dampeners/fuel pressure regulator
Direct-wired Aeromotive 340 pump
Custom TGV Deletes
IAG 8mm phenolic spacers
11mm STi Oil Pump
Killer B Oil Pickup
Perrin Catless Up-pipe
Nvidia Catless Down-pipe
Vibrant Catback
Moroso Alum Oil Pan
TD06 20G Deadbolt Turbo
TurboXS Front Mount
MAC 3 port EBCS
AEM 3.5 Bar MAP
GM IAT Sensor
K&N Short Ram
eBay GC Radiator
Spal Fans
Evap Delete
TurboSmart Vee Port Pro
Group N Engine Mounts

ECUMaster Black with custom patch harness
Autosport Linear Oil Temp sensor
Lowdoller fuel pressure sensor
Lowdoller oil pressure sensor
Prosport Water Temp
Prosport Boost Gauge
Mech. Oil Pressure Gauge
AEM UEGO with 0-5v output to ECUMaster Black
CANChecked multi-gauge
Shorai LFX36L Battery

Stock Clutch
Stock 5 speed
WRX 4 Pot Fronts
LGT Vented Rear rotors
LGT single pot rear calipers
1 1/16" 4 port master cylinder
Braided Lines
Hawk HP+ All Around
Group N transmission mount
Kartboy Shifter Bushings
Kartboy Trans Bushings
Kartboy rear outrigger bushing inserts
Whiteline Rear Subframe Lock Bolts
Whiteline Steering Rack Bushings

DMS 40mm Coilovers
Cygnus Performance X-1 Coilovers
'04 STi Steering Rack
'05 STi Front swaybar
JDM STi alum. LCAs
Sparco Front Strut Bar
Whiteline Front Endlinks
Whiteline Front Swaybar Bushings
Whiteline Rear Endlinks
Whiteline ALK
Whiteline Roll Center and Bump Steer Kit
Whiteline Rear Swaybar Mounts
Whiteline Lateral Link Bushings
Whiteline Trailing Arm Bushings
Whiteline 22mm RSB
Moog Adjustable Rear Lateral Links
ARP Studs

JDM STi Ver. 2 Aluminum Hood
JDM STi Ver. 2 Front Bumper
JDM Clear Taillights
JDM Front Bumper Beam

Old school OMP Wheel
NRG Quick Disconnect
Custom CF center console panel
Stereo/Airbag Delete

To be installed
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Picked up the Canchecked gauge and a fluid temp sensor from Ballenger. It's a 3 wire sensor so need to mess about with a pullup resistor or any nonsense. The gauge allows for 4 additional sensor inputs and communicates with the ECU, which is nice.

I'll be putting the temp sensor in the rear galley plug where I currently have a leak. When everything comes in I'll put in the oil pressure sensor i tried to install earlier, but now with a completed harness.

Whole bucket of bolts came in from McMaster, so changed out all the TGV,coolant overflow, and boost solenoid bracket
bolts. Won't notice them too much but better than the rusted hardware I had before.
Rim Bicycle part Auto part Circle Metal

Motor vehicle Grass Bicycle part Gas Auto part

Installed the remote oil pressure sensor. Ran out of ideas for proper mounting, so just zip tied it to the fuel pressure regulator.
Automotive tire Motor vehicle Hood Automotive design Automotive exterior

Waiting on the temp sensor, new gauge setup, CAN wiring, and 1/8 NPT galley plug. If the weather holds up I should be able to put everything back together next week.
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Parts started trickling in slowly. Threw in a new oil galley plug seal on the front, and the 1/8 NPT plug on the back next to the turbo. Let's hope the new copper washer will stop my oil leak at last!

Handed off my intake mani to a powder shop, my wrinkle spraypaint wasn't holding up at all whatsoever so I just bit the bullet.

The mod bug is out in full force yet again...taking out the manifold was a PITA due to the Perrin V1 fuel rails I have, they cut in front of the A/C compressor on the driver side and between the turbo and manifold on the passenger side. The setup uses the stock FPR, I'm not sure what flow it's rated for now that the Aeromotive 340 is in the tank.

I started the hunt for a clean setup and found a Radium kit. It's a partial returnless parallel setup, only one line to each rail which is really nice. Radium says it's only for 08+ STi's but i'm not sure why I can't make it work on my car, I'll have to email them to find out. When I get my new CAN gauge in, I'll be able to run both fuel temp and pressure off one sensor, a new Bosch unit just came out which looks really nice.

The whole setup with rails would be about 500$, which isn't bad, so someone please try to help my wallet out by saying the rails I have now are sufficient!
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Got no opposition, so I pulled the trigger. For anyone looking for parts cheaper than anywhere else look to Emnotek. Their prices are 20% lower than any other retailer so it sent up some red flags, but I got the rails and plumbing kit 2 days later with zero issues!

My Cygnus coils also came in, along with new hub bolts. They weren't cheap but my old ones are rusty and partially stripped.

Also ordered Radium fuel dampeners and a fuel pressure sensor that will integrate with the new CAN gauge.

Way too cold to do any wrenching, so all I can do is just look at pretty parts.
Intake manifold got back from powdercoating! Came out far better than I could ever do with a spray can.
Glove Gesture Pink Red Plant
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Damn that manifold looks nice. Now I wish I'd powder coated mine :cry:
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Damn that manifold looks nice. Now I wish I'd powder coated mine :cry:
Yours, along with the entire damn car, looks factory new! Did you spray your manifold yourself? I did the same but it soaked up every bit of gunk that got within a 5 foot radius and could not be washed off. I sprayed it in 90% humidity so it came out spotty as hell.

Now im looking at what else to :(
Thanks! I sprayed mine with VHT Wrinkle Coat red. I gave the manifold a hot bath scrub with dawn, then hit it with liberal amounts of brake clean before painting. It came from the importer decently clean so it didn't need much prep work. After painting I cured it using a heat gun for about an hour.
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I wire brushed mine and doused it in acetone. I think the humidity screwed me over as I also heat gun'ed it for a while.

Still waiting on my canchecked gauge, It ships from Germany so it might take some time.

Trying to come up with an easy way to wire the 2 additional sensors in, yet still leave the capability to use up the other 2 analog inputs. The gauge only comes with a single sensor + and sensor - wire, so I might split those into 4 somewhere close to the gauge and plug each into a separate 3 pin connector along with a signal wire. 2 will be used by oil temp and fuel pressure, then I will have the option to add 2 other sensors down the line.

Bought some wire sheathing for the additional sensor harness from Corsa Technic, it'll be my first time using it but I need some semblance of wire protection when it goes through the bulkhead into the engine bay. I already had enough electrical issues, don't want to run into more especially when I have the time and some know-how to do it right.
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Interested in seeing the wire sheathing.
Should have linked it before!
Expandable Sleeving Motorsport Wiring Harness Products - Corsa Technic (

MUCH cheaper than Raychem stuff, prob will work the same in the end. Will terminate both ends with some heatshrink to keep it in place
Not much going on lately.

Fixed my rear galley plug oil leak with a new oil temp sensor and adapter, gonna wire it in to the CAN gauge.

Sent my TGV's out to get powdered silver.

Still waiting on my Canchecked gauge! The guys over at Trailbrake were apologetic but kept shifting the ship date, apparently they are waiting on a shipment from Germany.

All my remaining sensors came in, now just waiting on TGV's to be done so I can start the fuel system, since it's a real DIY kit.

unpacked my coils from all the bubble wrap hiding them yesterday, they sure look purdy! Almost a shame to throw them on.

Also got new strut bolts, 120 bucks for all 4 corners stung a little, but nothing looks better than new hardware!
Audio equipment Coil spring Gas Cylinder Auto part
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Had a nice warm day so started to put together my fuel system. The ORB fittings come together so nicely, I'm not surprised people AN literally everything they can!

The parallel kit I bought was for 08+ STi's, so I knew there would be some modifications needed, and right off the bat I had to delete my windshield washer tank. It's a weekend car, plus weight savings so I don't miss it.

My previous PCV system was a mess of random fittings and hoses, so bought some 1/2 inch PCV hose and a bunch of standardized fittings. Might try to make things a bit neater now that the manifold is off.

Wheel Automotive tire Crankset Bicycle part Motor vehicle

Motor vehicle Automotive design Auto part Automotive fuel system Gas
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Picked up my TGV's from powerdercoating and started assembling the fuel system off the car. This shiny part addiction is getting stronger.....

Toy Fire hydrant Grass Plant Human leg

One unexpected benefit of the ORB/AN fittings is the level of line customization you can do. The area between my turbo and manifold was getting a bit full with 2 fuel lines, 1/2 and 3/8 PCV hoses, and wiring harness. With these new fittings, ill be able to run only 1 fuel line and i'll route it under the inlet!
Motor vehicle Electrical wiring Automotive exterior Hood Gas

Motor vehicle Automotive tire Light Automotive fuel system Automotive design

CANChecked gauge came in, ill post up better pics and maybe a vid when I get it installed...someday.

Also picked up a Shorai LFX36 battery with terminals, for a total weight of <5 lbs! I'll never drive the GC in winter so the small battery won't be a problem.

All my new PCV system fittings and hoses came in, now I have to figure out how to route everything and keep things clean and organized.
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Threw in the new fuel rails and lines, trying to get the push lock fittings on properly was an incredible PITA, will probably end up using hose clamps just for extra security.

Since it's been too cold to do much work, I decided to tackle my gauge wiring in preparation for the Canchecked gauge. My previous wiring was haphazard, multiple tees and taps off different 12v wires, mostly just held together with electrical tape and dreams. as this was a bit of a fire hazard, I decided to do things right and start anew. With new Molex connectors I created a modular gauge wiring harness for both the MFD15 and new canbus wiring.

Wrapped all the new sensor wiring with that stretchy mesh from Corsa Technic. It took some trial and error, but I eventually got the groove of things and progress went well.

Need to add new connectors to my patch harness for CAN integration and the new gauge should be good to go.

Redid my boost control solenoid wiring with proper waterproof Deutsch connectors too!

For the more keen-eyed viewers I did not terminate one connector since I'm finalizing the length, need to lay it out in the car but it's too damn cold!

Wood Jewellery Font Wire Metal
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Finally fired up the CANChecked gauge yesterday! Integration with the standalone was essentially plug and play. Input the scaling into the gauge and it sends the data off to the ECU without a hitch. The gauge cluster is still not fully in yet, still need to organize the wiring so I'll post up a short video sometime after I finish.

Thinking of getting a rotary switch so that I can play around with map switching or blending, just need to find a place to mount it.

Have some work left in the engine bay for PCV system routing, 1/2" hoses are a serious PITA to route. Still have to pressure test the new fuel lines and see if they'll hold up to my target 70 PSI.

Picked up a 1 1/16" master cyl from Amazon along with a bleeder kit, hopefully it'll improve my brake feel a bit.

Bought Hella horns and a Perrin bracket, but my USDM bumper beam is too tall, So I have a JDM beam on order. Costs are really stacking up....200+ bucks just to install 30$ horns, but at least I'll be shaving off an additional 30 pounds!

All this work I'm putting in is bittersweet though. Would have loved to share some ideas and plans with my dad as I went along...I'm still coming to terms with how much time and effort he put into not only this project, but everything else he had in life. Although I like to think he'd be happy with the way everything's going.
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Just went through whole thread. nice work. good luck in the future.
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Thanks, I appreciate it!

Threw in a new 1-1/16" master cylinder:
Dorman #630616

Fits like a glove for non-abs imprezas! Bleeding it was a bit of a PITA, but the install went fine with the right tools. I'll bleed the brakes when I throw on my new coilovers. Haven't taken her for a spin in a long time so can't say there's any difference in pedal feel for now.

Finished up the gauge wiring layout, and routed the Canchecked control knob to a blank in the center console. It's nicely recessed so I won't accidentally bend it, but sticks out just enough to have ease of control. The CAN integration is super simple, and picked up every output from the ECU without an issue. For now, it's directly connected to my oil temp and fuel pressure sensor, plus one input from my wideband o2, which transmits AFR to the ECU, freeing up a precious input on the ECU.

Considering picking up a mux switch so that I can run 3 on/off switches off of one input but shipping from the UK is 50 bucks for a 13$ part : (

I'll post up some shots soon of the new setup for anyone interested.
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Nice weather means more work.

My old wideband was giving me erroneous data so I picked up a new AEM UEGO kit and wired that in. Also ran new nylon line for my mechanical oil pressure gauge, as a backup to my Canchecked gauge.

Considering getting an ECUMaster 4 or 6 button keyboard for boost map switching, LC, antilag and other fun stuff. need to create a template to see where I can mount it.

Got my front coils in also. Geoff's site says to adjust the height via the lower perch but I followed @Stew3223 's build thread and did the opposite! Now I need to pick up a set of helper springs since I'm back to OEM ride height with almost no preload. The spring barely hangs in at full droop, so any lower and it might completely unload if I hit a bump or get too aggressive in the corners.

It's such a pleasure doing suspension work on a rust-free chassis, I had the shocks out in less than 3 minutes. My DD is a B8 A4, and manages to amaze me how complicated new cars are to fix and work on. Plugs are of course easier, but any suspension or engine work is laughably simple compared to my Audi.
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Those Radium fuel rails look so nice. Also, nice work on the wiring - nice and tidy. Are you doing anything special with the CAN output? I know one of the advantages of the ECU Master stuff is that their CAN architecture is MUCH more open and flexible.
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Thank you!

The rails and ancillary stuff was a bit pricy but it's really nice. Shame they'll be taken u

I took my time with wiring this time around and made all my connections very modular, so gauges can be easily swapped/disconnected without having to splice.

I have not delved into CAN outputs too much just yet, All I have are 3 sensors feeding my CANChecked gauge which then sends that data to the ECU, and that was super easy to set up, just get the bitrate right on both devices and enable the CAN inputs on the ECU. the ECU also outputs tons of data to the gauge. I'm thinking of getting a can keypad to control boost, Cyclic idle and some other switches, but I'm at a loss of where to potentially mount it. MY center console is already full of gauges and the area around the gauge cluster is too small to support even a 2x2 board, and I definitely don't want to be putting holes into any existing interior trim that cannot be easily replaced.

Setting custom CAN messages is simple too, although I haven't had a reason to play around with that just yet.

I don't think i'll be setting up a PDM soon, it's a ton of work and money for not too much benefit at least for me. With crank windows and manual everything else, it would only potentially control my lights, wipers and rad fans.
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