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1988 Mazda 626GT Build.

Discussion in 'The Turbo "Builds" Board' started by MazdaCarnage, Oct 17, 2022.

  1. MazdaCarnage

    Jul 8, 2022
    I have been driving and working on these cars since 1998.

    In 2012 one of my friends (started as a shop customer) sold me his 1988 626GT after he lent it to his brother who put in 87octaine and the engine blew. I paid 450$ for the car, it came with 2.5" exhaust and a stage 3clutch and lightened flywheel.

    When the 1992 MX6GT I was driving (same car but 2door) got too rusty I threw together a block and put it in the 626GT, I used junk and parts I had lying around the garage and the bumpers, fenders, hood and headlights off a matching color 626lx automatic parts car I had.
    This was a zero budget build and I treated it as such.

    This was the engine bay after pulling the motor and I am ashamed to say I left it like this:
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    I changed the bumper, hood, fenders and headlights after dropping in the engine.

    Here is a picture of the car completed, it was raining and the car almost looked shiny:
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    Just like the engine bay the rest of the car had rust, the car looked just shitty enough that the cops left it alone but was starting to rust enough that it was going draw their attention.
    I was going to start welding it up when someone told me there was a base model from out west with no rust for sale nearby so I bought that car for a replacement body.

    It was meant to be a direct swap, just gut and paint the new body and swap all the parts but if I was going to do that much work I might as well find a way to make it take 50X the effort and 1000X the time, why not I only have 3 MX6 GT builds on the go.

    Keep in mind there was very little aftermarket support for these cars (none now) and no transmissions or heads that are upgrades and bolt to the block...

    The new body had rust on the rear strut towers, the factory metal strut mount caps had rusted and spilled to the strut towers, I cut the rear strut towers out of the 92mx6GT and welded them in.
    I stripped the interior floor paint from the firewall to the trunk and put on two coats of POR15 and two coats of armor coat.
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    Sandblasted the entire front end and wheel wells and coated them in POR15, armor coat and roll on gravel guard.
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    I wanted to pain the car the same color as the rusty original but my friend, who I rent a garage from and who runs a body shop refused to paint it that color and was taking for ever to start on it so I chose Lexus Ultrasonic Blue Mica 2.0 as the color to get back at him, a choice that I will surely pay for once the car is on the road, here in Quebec there are very few cars that are more than 20 years old, if it's an older car in good shape in bone stock form and just looks like cheap basic transportation to and from work the cops leave it alone, if it looks like you love the car and care about it the cops make it there life's mission to pull it over every time they see it and try to take it off the road.

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    This paint has many different hue's of blue depending on lighting.


    This project went from a simple parts swap to very few of the same parts getting used on the new body, things had rusted too much.

    The list of parts that made the cut are:
    -Heavily ported intake manifold.
    -Heavily ported exhaust manifold and turbine housing.
    -The turbo.
    -The ECU and half the wire harnesses.
    -The spoiler.
    -The bumper skins (front and rear).
    -The struts.
    -And parts I put on the car like the 255lph pump, injector controller, meth set-up...

    Old Car just rusting away:
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    At this point I decided that 4 project cars are unrealistic so the parts for 3project cars got divided by two and I started the build.

    The plan was to coat everything in POR15 but it's messy, expensive and hit or miss on the gloss and leveling on humid days it can dry too fast and look like crap... I have everything needed to powdercoat but never got set up to do so since I moved the shop in 2010. I just needed to build another powdercoat booth and set the rest of the equipment up.

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    Disney Lincoln likes this.
  2. MazdaCarnage

    Jul 8, 2022
    I chose Jollypop candy red (not for the name), it's a translucent top coat that requires a shiny base and proceeded to coat everything under the hood that could handle the heat of and fit in the oven, spent months sandblasting and powdercoating parts.
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    What I couldn't powdercoat I sandblasted and coated in Por15.

    The assembly:
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    Front end work consists of:
    Sand blasting and por15 coating the rack and pinion and most of it's lines (Brackets and some lines where powdercoated.), the crossmembers and brake master.

    The control arms where sand blasted, link kit reinforcement plates welded to them, front end tie down loops welded to them, new press in ball joints with retaining clips tack welded to it and poly control arm bushings pressed in.

    The spindles hubs and calipers are coated in port 15 "red" caliper paint (it's orange), took a 50/50 mix of car pain pigments (true red and black) to get it where it is so I top coated it all in VHT clear. The spindles have new bearings, the ball joint retaining bolt hole is drilled out from the factory M8 bolt to M12 bolts (keeps the ball joint stem from grooving into the spindle and wearing out the ball joint). Rebuilt the calipers. New bearings in the spindles.

    The swaybar is a 1" thick solid Adcco sway bar, it tends to brake link kits, the poly link kits and cups are drilled out and 1/2" mild steel bolts replace the 5/16" originals. chose mild steel because it will bend before it breaks (lost a lot of lifetime warranty poly link kit bushings over the years, if you just upgrade the bolts it's rips through the control arm).

    Poly front and rear motor mounts with 1/4" holes drilled through them (97A poly, even with hole through them to give them a little play every nut and bolt needs locktite).

    The firewall heatshield is building insulation bubble wrap.

    Every bolt and nut was sanblasted or soaked in apple cider vinegar and blackened with eastwoods bolt blackening kit (didn't work most are already rusting (later problem)

    The brake lines and fuel line under the car where in good shape so the stayed on the car, along with the fuel tank, windshield and back glass and 3 of the doors (not the glass or any of the 100pieces the go on and in the doors) everything else got changed.


    The engine:

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    Whats been done to the engine:

    Factory block, original pistons, rods, bearings and crank. The pistons and rings where cleaned, the cylinder walls honed and reassembled with new seals and gaskets. Block and pan are coated in POR15.

    The head is ported as much as it can be, the valve seats are cut back, manually decked until clean and true, cc'd the combustion chambers and ported them until compression was down to 7.5:1 from the factory 7.8:1. Installed 0.06" valve spring shims and new valve seals.
    Thermo gasket spacers have been ported and installed between the head and intake, upper and lower intake and at the throttle body, the increase the intake runner length by 1/2".
    The intake manifold was ported.

    The factory throttle body has two butterfly sizes, the auto has a large primary and small secondary and the 5speed has a small primary and large secondary, this is a 5speed throttle body I ported the upper hole by hand and installed a larger automatic primary butterfly and shaft.

    The alternator has not been cleaned or touched because once the last 626 got to 30psi it started killing alternators. That is why the engine is running an aluminum underdrive pulley instead of the factory pulley with rubber balancer, would rater run the factory pulley especially on poly mounts but I am taking several steps to stop burning alternators (more to come).

    Ported the fuel rail and deleted the factory regulator. The rest is all just powdercoated.

    The Valve cover was powdercoated in 2005 and a candy red but has faded to pink over the years, I will powder coat another valve cover for the car after it's running.


    For reliability reasons and to make certain nothing on the car is shorting out (alternator) I removed the tape and loom from every wire harness for the car, checked every wire, splice, connection and connectors.
    Replaced anything with corrosion, relocated interior connectors when needed, added speaker wires, control wires or power wires where they where needed and re taped everything.

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  3. MazdaCarnage

    Jul 8, 2022
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    + the four door harnesses, engine ground harness, interior firewall harness, dash harness, trunk lid harness...
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    The interior.
    The rusty 626GT has a burgundy interior, the guy who sold it to me cut the carpet out on the drivers side? And asked if he could have the seat from my matching 4door, I said yes and he cut the carpet out of that car too, no carpet pieces came with the car and burgundy sucks.
    The new body was a DX with garbage interior, so I pieced together blue interior parts I had everywhere and have enough to do the car.
    The doors where manual window and every piece of trim, molding, nut and bolt got changed, the best parts from 19 mazda 626 doors where used to make 4.

    Cut out new insulation film, sealed the doors and installed blue doors skins with speakers in them stored in my basement for the last 20 years.
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    Other interior work and mods can be found here:

    The carpet was old and worn so I brought it home, cleaned it, patched it, removed the rotting underside insulation and replaced it with cheap light 3/8" foam mat (waterproof, mildew resistant and doesn't crush). If there is mat left over after doing the backseat and trunk I will cover the front floors with layer before installing the carpet.

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    The interior will be pretty much stock with six 2" gauges added to the dash, a grant steering wheel, hardwood hand carved shifter and leather shift boot, a bunch of toggle and rocker switches, extra injector controller... The front seats are for an MX6 they are blue but have a different upholstery than the rest of the car, I have been shopping for upholstery to replace that section on the seats with (don't have any 626 blue front seats left).
    Sound system is four extra door speakers running off a 1996 sony 4way 400 watt amp under the passenger seat (set to 50% gain), a JVC head unit 4x50watt running 2 4" dash speakers and 2 9x6 rear deck lid speakers. (doesn't have to be loud, just clear).


    Exterior mods:
    These are few and far between, I transferred the spoiler I had put on the rusted 626 (found it in a junkyard and matched the old 626 color exacly) this is a purely visual mod on a front wheel drive.
    I chopped up two 626 badges and made an 666 badge for the rear of the car. Installed some fog lights I bought years ago marked down from 60$ to 7$, painted the front grill badge in white paint that glows aqua blue in the dark (I know it's ricey) and powdercoated the 1997 Ford probe GT 16" rims.

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    (painted 3 and will use the middle one)

    I have several sets of aftermarket rims but the factory probe rims are light, strong, have the perfect offset.
    I ordered crazy chameleon blue and dormant blue, figured the way dormant colors work it should have infinite depth.
    The dormant blue looks purple to the human eye and can only be captured properly in direct sunlight with a flash by a camera (doesn't look this way even in the sun).
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    So the crazy chameleon it is.
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    Pro-SC and Disney Lincoln like this.
  4. MazdaCarnage

    Jul 8, 2022
    Now back to the engine and engine bay.
    Decided to upgrade the modified factory intecooler.
    Modify the hood latch to cleat the intercooler.
    Add Exhaust gas re circulation.
    Redo the intercooler pipes.
    Install a BOV and BPV .
    Add an outside air path from the drivers fender.
    Relocate the air horn.
    Change the bumper port vents to deliver air the the larger intercooler.
    And make an Isolation box for the air filter.
    Reweld the injector bungs, reinforce the meth jet threads...

    Everything bolts to factory mounting points.

    Engine installed:
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    Air feed and air horn:
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    Mild steel, powdercoated, with injector bungs, wategate port, BOV, BPV, IAT sensor, two water meth jet reinforced threaded holes and stainless M6 bolts welded to them to mount to custom brackets that bolt to the body.

    Air inlet pipe with fittings for BPV, PCV and boost control return air:
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    Stainless ghetto air filter box, didn't have a big enough piece so I welded 2 together but it's 18gauge and my welder wanted to melt it, was going to use it as a template and make another out of lexan but it took so long to roll the edges of the stainless using a vice and round file (yes the file broke) a no cost solution was to grind down the weld and dowce it in powdercoat I had kicking around from 2006, I hot coated it by pouring the power on it and spreading it with a paint brush:

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    Pipe support brackets:
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    Bumper vent deflectors:
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    Disney Lincoln likes this.
  5. MazdaCarnage

    Jul 8, 2022
    What the bumper vents do and the fog lights:
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    I powdercoated the bumper mounting brackets and headlight brackets and cleaned and painted all the fasteners:

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    The oil cap and EGR pipe have been powder coated black since this picture.

    More to add to the thread, will continue tomorrow.
    Disney Lincoln likes this.
  6. MazdaCarnage

    Jul 8, 2022
    I know this isn't the type of build normally posted here and I know it seems like I am obsessed with coating everything and making it look ricey but it's all in the goal of stopping rust and corrosion. Here brand new painted rock auto parts rust within six months and look like they where on the car from factory.
    Here was the intercooler after I welded 2.5" fittings to it and coated it in matte black spray paint. To put on the rusted 626when I got it: (black spraypaint lasted a few months).
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    Here it is after 5years of driving on the rusted 626 (after sand blasting):
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    Corrosion was eating through the supports and covering the tanks.
    I sand blasted and powdercoated the end tanks and mounting brackets and peeled the first layer of corroding fins off the front, used black body shop primer and spay paint to coat the fins this time:
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    But I didn't like the fact that the end tanks would now dissipate less heat on this overtaxed factory intercooler due to the powder coat, so I upgraded the intercooler, had the upgrade sitting in my basement for years but was trying to avoid modifying the hood latch assembly (against the law, unless inspected by a provicial engineer) and having to run the pipes across the turbo and manifold. The new intercooler will be coated in Cerakote C-102 matte black ceramic coating, it dissipates heat and resists corrosion and will make the hideous front mount intercooler disappear behind the bumper. Will find out how tough cerakote really is.
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    A few pictures that go with what has already been posted:
    -Head port work
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    Ported manifold (stock above)
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    Flux core welded T3 flange
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    Ported turbine housing
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    Enlarged wastegate port WP_001594.jpg #ad

    Ported intake manifold
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    The interior parts being used (without the seats):
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  7. MazdaCarnage

    Jul 8, 2022
    The transmission:
    This cars transmission is how I met Rob the previous owner of the rusted 626, about 18years ago someone sent him to my garage because after getting his engine back from the machine shop he was so excited that he started the engine with no axles in the transmission and the axle gear spun in the diff and everything was out of alignment so I rebuilt it for him.

    The transmission is factory but I tore it down again, change the shaft seals, weld the differential shaft to the differential housing, it's normally just held in place by a 1/4" roll pin that will shear off and send the differential shaft though the transmission case.

    The clutch and flywheel got upgraded, the rusted 626 ran a stage 3 bulley clutch and a factory flywheel with 12lbs of steel removed from the back side. The new 626 has a 10lbs aluminum flywheel and bulley stage 4/5 clutch. It uses a stage 5 pressure plate with needle bearings rated for 700ft/lb with soft pedal engagement, the disk has the sharp edged shape of the stage 5 pucks and uses the same material sintered steel(no break in required) as the stage 5 disk but has 6puck like the stage four instead of 3 like the stage 5 making it better for the street.

    Tore down some CV-joints, put in new grease and axle boots, cleaned them and coated them in por15.

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    Powder coated the cap and clutch fork because they where rusty, used the dormant blue powdercoat because I paid for it and these parts can't be seen.
    Have plans to powdercoat another transmission at some point down the road.

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    Stage 3 upper. Stage 4/5 lower.

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    Here is where the 12lbs was removed from the back of the factory flywheel, had three of these machine out and surfaced years ago, after spending 600$ on the aluminum flywheel, it's still about 23lbs heavier than the aluminum flywheel but cost 1/6 the price. The stage 5 pressure plate is so heavy both assemblies weigh about the same.

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    The back end of the car:
    Coated everything under the bumper in POR15 .
    Coated 4 new trailing axle arms and installed them. Installed performance trailing axle links with poly bushings, Installed and 3/4" solid adcco swaybar with poly bushings and link kits with larger bolts. Reinforced the mounting tabs for the sway bar on the trailing axle. Installed a lower trailing axle bar and upper strut mount bar, the rear got new disks and bearings, rebuilt calipers, new handbrake cables, coated calipers and spindles, performance struts and 1" lower performance springs (I ran them on the rusty 626) added thicker spring seat rubbers that raise the car 1/4" and stiffen the springs a bit.

    The front runs the 1" drop performance springs and performance struts with new upper rubber spring seats, added lower rubber spring seat rubbers and metal shims between the strut mount bearing, increasing the preload on the springs and increasing the spring rate and raising the car. The factory control arm bushings have up and down resistance but the poly bushings have greased floating metal sleeves so the control arm have no up and down resistance, I am trying to make up for that with stiffer springs.
    If the poly control arm bushings don't keep the control arms from moving forwards or backwards under torsion causing torque steer I will make front wheel drive torsion bars for the control arms if the poly bushings driving performance is better than factory, if not I will go back to factory style bushings with travel limiting washers welded to the control arm, The washers eliminate any back and forth movement of the control arm and eliminate all torque steer.

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    Random hidden parts coated in dormant blue

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    Keep in mind although I had 50+ pounds of powdercoat from 2008 and older I didn't want to use any of it because I tried test panels with the old super durable clear and it was clumping and not flowing out during curing. I had purchased chrome, candy red, clear, dormant blue and crazy chameleon, and was out of crazy chameleon so I coated the whipper arms dormant blue.

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    Since then I have ran test panels with some of the other 14+ year old powder coat and started using some of it again, only the clears seam to have been effected from sitting so long, the black on the intercooler pipes is old powdercoat.
    I might have to coat another set of wiper arms if these look too ricey on the car, the springs are such a struggle to remove and reinstall, have to hammer washers between the coils of the spring to space it out enough to remove it from the arm.

    The ECU housing was corroding away so I powdercoated a box that was in good shape and installed the boards in that.
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    This sits inside the car, under the dash on an elevated bracket, the liquid sodium they put on the roads gets into everything, even when it's never winter driven.

    Mounting bracket
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    16year old screaming eagle black crinkle powder coat
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    I needed to run 9 bulkhead fittings through the firewall, for the air horn, water/meth, boost control, bov/bpv control and water/meth vacuum manifold. No local stores have what I need, I can find them cheap online but shipping to Canada was insane.

    The ID10T I rent the garage from bought a decommissioned private passenger jet so I pillaged all the AN fittings and hose fittings I could get to:
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    Got enough bulkhead fittings to do the whole car. The brass barbed fittings where on the car or going on the car.

    And some hose
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    I really like these hose fittings, you crew the socket onto the hose, insert the nipple into the AN cap and screw it into the socket and hose, rated for 200psi, easy to connect and disconnect (unlike barbed fittings).
    These will replace all or most of the barbed fittings I added to the car. They can even be used with hose that isn't the right size for the socket, like the BOV/BPV hose I will just use the AN cap and nipple and a hose clamp to hold the hose to the nipple, the AN cap will still connect the same way.
    Pro-SC and tbird like this.
  8. tbird

    Sep 1, 2004
    I remember you from a Mazda/probe gt forum.
    Been years since ive check those pages out.
    I have a 91 gt just sitting
  9. Pro-SC

    Feb 8, 2014
    I have had luck removing the moisture from old powder using rice. Just add rice to a bag of powder and let it sit for a few days, filter out with a sifter and just like new.
    20112011Cummins likes this.
  10. 20112011Cummins

    Jul 4, 2014
    I got here from the electrical thread. Very cool build!
    MazdaCarnage likes this.
  11. Twin Turbo Skylark

    Dec 16, 2009
    Hello from Alberta, great attention to detail!!! Keep going it looks great
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