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Just another lowly GM6 build

12461 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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What do you have for a steering wheel? If you use a aftermarket type wheel and quick release, I've seen it done where you can hide a small analog to CAN board either on the back of the wheel or between adapters. Then you can use some regular switches (Otto P9 are nice) and program the analog to CAN to send messages corresponding to each button press.
I have an old school OMP on an NRG quick release. I thought about this idea before but without a clock spring making the connection to the ECU will be challenging, i wouldn't want a coiled cable dangling around. I could mount something to the steering column shroud...!
Considering retiring my current set of wheels with something more classic like Speedlines. The seemingly only US distributor (Mann) seems to have cornered the U.S. market and thinks 575$ for wheels that sell for half the price in the UK is fair, so i'll have to import them.

Now the most difficult choice is 2013C vs 2120, and color.

the 2013C with the deep hub are far more expensive because they have to be custom machined and are only offered in 32 offset, so fitting them might be a challenge. the 48 offset ones unfortunately lose the deep hub, but retain the classic tarmac rally look.

I'm leaning a bit more towards the 2120's since they have the deep hub, look amazing, and are a bit cheaper.

Color choice is rough, since my GC is red instead of WRB :( I'd love to have a set of gold wheels, but they would clash with red. White seems to be the next best choice to retain that classic rally look.

What do you guys think?
Car Automotive side marker light Land vehicle Vehicle Wheel

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Who knew changing damn headlight bulbs could be so difficult? had to take the whole front off, I thought older cars were supposed to be simple!

Threw on the new JDM bumper beam, it might as well be made of paper mache and bubblegum. It's only real use is to hold the front bumper up.

The intercooler was bolted to the old bumper beam so I'll have to figure out how to mount it to the new beam, since it's much shorter. I'll prob put a bolt through the top and into the M8 holes of the intercooler, the bottom is firmly supported by two thick brackets.

I was a bit afraid to take the front bumper off, after 10 years of exposure to the elements with just a car cover i assumed the front end would be just a little bit rusty, but nope! Lots of dust but no corrosion at all.

With the new bumper beam on, the Hella horns fit like a glove. I jury rigged the wiring just to test em, and damn they're annoying!

I will need to order new intercooler couplers, the ones you see in the shot below are a bit old and cut up, and since they're inaccessible with the bumper on, might as well change them out.

Otherwise I'm still waiting on my helper springs to come in so I can finalize the suspension.

Got some completely unnecessary bling from RPG Carbon. I thought it would replace the stock fuse cover, but it's an overlay. It's not a big deal since it fits so well without any adhesives, but a direct replacement would have been nice.

Vehicle Car Hood Motor vehicle Automotive tire

Grille Automotive lighting Hood Motor vehicle Bumper
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Those fuse covers do get pretty faded over time. I ended up painting mine. Makes a world of difference in appearance. Looks good!
Color choice is rough, since my GC is red instead of WRB :( I'd love to have a set of gold wheels, but they would clash with red. White seems to be the next best choice to retain that classic rally look.
I think both would look amazing on red. Gold and red really doesn't clash IMO - I have '98 Goldies on my Brilliant Red wagon and I love the combo. It definitely stands out, but so do white wheels tbh.

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Those fuse covers do get pretty faded over time. I ended up painting mine. Makes a world of difference in appearance. Looks good!
Thanks! I painted mine years ago but the paint has since faded from exposure. A little carbon bling

I think both would look amazing on red. Gold and red really doesn't clash IMO - I have '98 Goldies on my Brilliant Red wagon and I love the combo. It definitely stands out, but so do white wheels tbh.
Yeah gold looks solid on your wagon! It'll def be a hard decision, but I'm leaning slightly towards white, if any place has the motorsport version of the 2120's in that color and fitment I need.

The 2120's, albeit on an evo, really stands out.
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Nothing against the gold, but your red just wears white so well!
Still haven't settled on a set of wheels, but I found out white 2120's aren't available in my size :( An unexpected trip ate up my wheel budget, so that's on the back burner for now.

Awaiting my front helper springs from Feal, taking forever to get in the mail. Can't wait to finally get the suspension sorted.

Need to get all the PCV routing done, change driver side valve cover gasket, then i'll be able to fire it up with the new fuel system and new sensors. Hopefully this Monday!
Lots of progress over this long weekend!

First up my helper springs came in, which allowed me to finalize the suspension setup. Here's the current ride height:

Next up I threw in longer ARP wheel studs. Front's went in without a problem but sweet baby jesus were the rears a pain in the ass. Since I have press in bearings, I tried literally every approach to get them in. Finally managed to get them into position but only after unbolting the caliper/ebrake backing plate and giving the bolts a small love tap with a hammer to get them into position.

I picked up the shorter 2.65" studs. There is no way in hell will anyone get the 3" in without a press or drilling the backing plate, just not possible.

Also gave my daily some TLC with some new shocks and lowering springs.

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She's alive again! spent some time putting the odds and ends together and she fired right up without a hitch. Need some minor details like the front bumper and the speedo cable which refuses to go back into the transmission, I'll have to figure out how to get it back in, or find an alternative.

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Drive by wire with a speedo cable is quite a combination!
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Drive by wire with a speedo cable is quite a combination!
Not sure if I can use a newer GC cluster that supports electronic speed sensor! Would be nice to feed the ECU speed data though.

It sure is an interesting setup....No ABS, OBD2, airbags or power windows but it has a standalone, CAN, and DBW haha

New CAN gauge works perfectly with very minimal setup. ECU picks up the analog inputs without any problems. Having to scale the inputs on the gauge and again on the ECU is more work, but it's only a minor hassle.

Having an issue with my ECU not turning off after key off. Motor shuts off no problem though. I'm guessing its a grounding issue? I only added the oil pressure sensor to the stock harness, I disconnected it and yet the same problem occurs.

Next up I need to hardwire my gauges to stay constantly on while cranking. My wideband takes 5 seconds to warm up, CAN gauge is about the same. I'd like to be able to see startup oil/fuel pressure but not sure where I can tap into to get switched 12V without it getting interrupted while cranking.

I'll attempt a rudimentary alignment sometime soon.
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Unfortunately a newer cluster wouldn't fit well in your dash, does the cluster have a speed signal out to the ECU? I was under the impression they did.
Unfortunately a newer cluster wouldn't fit well in your dash, does the cluster have a speed signal out to the ECU? I was under the impression they did.
I'll have to take a look, not exactly sure. I doubt the stock ECU needed speed info for anything but I might be wrong.

I'm not sure quite how to read the schematic, but there is an electronic VSS signal that's created in the cluster.
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I was just about to post the same screenshot! I'll have to do some more reading for sure. Thanks for pulling this up!

Looks like there is a connection to the ECU:
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No problem! The one thing that sort of confused me was whether that VSS is only present on the turbo models or not, as the cluster does have the one part that's turbo specific.
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