Mike's 2003 Mazda MX-5 NB2 Turbo build
Just another trubo NB2
A 2003 Mazda MX-5 NB2 built into a home-built turbo project
Mike acquired a partially-built turbo NB2 Miata from a former chump-car racer after a string of accidents wrecked his previous NA project. He has been reworking the turbo setup with a megasquirt-style ECU, a head swap after an oiling failure, a reseal, suspension and brake upgrades, and new wheels and tyres, documenting ongoing progress and setbacks including a hurricane that delayed the build.
Specs
As stated in the original write-up.
- Engine
- 1999 BP4W head on 2003 VVT bottom end, ARP head studs, Flyin Miata GT2560 turbo kit, Skunk2 intake manifold and throttle body
- Intercooler
- Mishimoto intercooler with custom piping
- Cooling
- CSF radiator, Supermiata coolant reroute, Gates water pump and timing belt
- Management/Fuel
- Megasquirt MS3 Pro PNP, Innovative LC2 wideband, Injector Dynamics 1050cc injectors, DW 255lb fuel pump, Radium dual feed fuel rail
- Gearbox
- 6 speed Mazdaspeed transmission with Flyin Miata happy meal kit and 11lb flywheel
- Brakes
- Front Wilwood big brake kit, rear Stop Tech sport pads
- Gauges
- CANCheck multi gauge installed for AFR and boost monitoring
- Shifter
- Mazda Roadster tall angled short shifter with Circuit Sport shift knob
Parts used
Parts named as used in the original write-up, grouped the way the Parts page groups them. Where one of the shops we index lists the same thing for this car, it is shown underneath with a link to the shop.
Engine 3
- 1999 BP4W cylinder head
Swapped in after the original VVT head's exhaust cam journal starved of oil and was damaged
In the shops
Head Gasket Kit (1999-00) ↗
Flyin' Miata· $319.00 USD
Cylinder Head Stud (Short) ↗James Paddock Ltd· £5.85 GBP
Cylinder Head Stud 6.25" (MG) ↗
bpnorthwest.com· $12.99 USD - ARP head studsARP
Installed during the engine reseal after the head was checked for flatness
In the shops
ARP Head Studs (NA/NB) ↗Flyin' Miata· $189.00 USD
ARP Head Stud Kit (Mazda Miata) ↗
MiataSpeed· $140.00 USD
ARP Main Cap Studs (NA/NB) ↗Flyin' Miata· $139.00 USD - Flyin Miata GT2560 turbo kitFlyin Miata
Core turbo kit carried over from the prior owner's build
In the shops
Flyin' Miata Stage 1 Turbo System (1994-95 Miata) ↗Flyin' Miata· $4,837.99 USD
Flyin' Miata Stage 1 Turbo System (2006-15 Miata) ↗Flyin' Miata· $5,299.00 USD
Flyin' Miata FOX Suspension Kit ↗Flyin' Miata· $2,389.00 USD
Fuel & Ignition 6
- Skunk2 intake manifold and throttle bodySkunk2
Fitted as part of the turbo engine package, later modified slightly for injector clearance
In the shops
Skunk2 Pro 64mm Throttle Body ↗
Moss Miata· $379.75 USD
Pro 64mm Throttle Body (Skunk2 Racing) ↗Moss Miata· $379.75 USD
Throttle Body, 64mm, pro, Skunk2 Racing ↗Moss Europe (UK)· £578.50 GBP - MS3 Pro plug-and-play Megasquirt ECUMegasquirt
Engine management relocated to the glovebox from factory mount location
In the shops
Haltech Elite 750 ECU with Plug'n'Play Harness (Mazda Miata 01-05) ↗MiataSpeed· $1,495.00 USD
Haltech Elite 750 ECU with Plug'n'Play Harness (Mazda Miata 90-95) ↗MiataSpeed· $1,495.00 USD
Haltech Elite 1500 ECU with Plug'n'Play Harness (Mazda Miata 01-05) ↗MiataSpeed· $1,793.00 USD - Innovative LC2 widebandInnovative
Used for air/fuel monitoring on the turbo setup
In the shops
60A Poly Engine Mount by Innovative Mounts ↗Moss Miata· $303.25 USD
Innovative Mounts 60A Poly Engine Mount, 1.6L ↗Moss Miata· $291.75 USD
Innovative Mounts B-Series Rear T-Bracket ↗
JDMuscle — Mazda MX-5· $104.97 USD - Injector Dynamics 1050x injectorsInjector Dynamics
Required manifold clearance grinding to fit correctly with the Skunk2 manifold
In the shops
Diode Dynamics HP5 LED Rear Side Marker Bulbs (194R) ↗Flyin' Miata· $24.99 USD
Diode Dynamics HP11 LED 3rd Brake Light Bulb (1156R) ↗Flyin' Miata· $34.99 USD
Diode Dynamics HP5 LED Front Side Marker Bulbs (194A) ↗Flyin' Miata· $24.99 USD - Radium dual feed fuel railRadium
Paired with the ID1050x injectors on the BP4W head setup
In the shops
Dual Feed Fuel Rail Kit ↗Moss Miata· $369.75 USD
Radium Engineering Fuel Pump Hanger Dual Pump Add-On (94-01 Integra / 92-00 Civic) ↗JDMuscle — Mazda MX-5· $132.95 USD
Catch Can Kit by Radium Engineering ↗Moss Miata· $469.95 USD - Deatschwerks 255lb fuel pumpDeatschwerks
Fitted to support higher fuel delivery for the turbo build
In the shops
DeatschWerks Fuel Pumps ↗Moss Miata· $102.99 USD
Fuel Pump, 165lph, Deatschwerks ↗Moss Europe (UK)· £161.26 GBP
Fuel Pump, 255lph, Deatschwerks ↗Moss Europe (UK)· £161.26 GBP
Cooling 3
- Mishimoto intercoolerMishimoto
Fitted with custom piping to complete the intercooler setup
In the shops
Mishimoto ND2 Oil Cooler Kit ↗MiataSpeed· $791.95 USD
Mishimoto 155°F Racing Thermostat ↗MiataSpeed· $72.30 USD
Mishimoto Aluminum Fan Shroud - Gold ↗MiataSpeed· $344.75 USD - CSF radiatorCSF
Installed as the upgraded radiator for the turbo build
In the shops
CSF Replacement Radiators ↗Moss Miata· $113.99 USD
Radiator, replacement, CSF ↗Moss Europe (UK)· £209.26 GBP
Radiator, replacement, CSF ↗Moss Europe (UK)· £209.26 GBP - Supermiata coolant reroute kitSupermiata
Used to improve cooling system routing
In the shops
Coolant Reroute Kit ↗Flyin' Miata· $471.99 USD
Coolant Reroute Kit ↗Moss Miata· $338.00 USD
Coolant Reroute Kit ↗Moss Miata· $216.99 USD
Gearbox & Drivetrain 1
- Mazdaspeed 6 speed transmissionFlyin Miata
Swapped in with a Flyin Miata clutch kit and lightweight flywheel
In the shops
Mazdaspeed Intake Package ↗Flyin' Miata· $1,025.00 USD
Mazdaspeed MX-5 Intercooler Upgrade ↗Flyin' Miata· $439.00 USD
Head Gasket Set (2004-05 Mazdaspeed) ↗Flyin' Miata· $329.00 USD
Suspension & Steering 3
- Extended ball jointsPaco
Fitted alongside the coilover install
In the shops
Extended Lower Ball Joints ↗Flyin' Miata· $129.00 USD
Extended Lower Ball Joints ↗Moss Miata· $149.75 USD
Lower Ball Joint, extended, Flyin' Miata ↗Moss Europe (UK)· £203.00 GBP - Supermiata adjustable endlinksSupermiata
Paired with the upgraded front swaybar
In the shops
Pedders Adjustable Sway Bar Endlink Kit (11-13 Corvette) ↗JDMuscle — Mazda MX-5· $134.96 USD - Harddog HC rollbarHarddog
Fitted to the chassis as part of the rollover protection and bracing
Brakes 2
- Wilwood front big brake kitWilwood
Fitted for improved front stopping power, carried over from the prior NA project
In the shops
ND Stage 3 Wilwood Big Brake Kit ↗Flyin' Miata· $1,329.00 USD
Front-Only FM Big Brake Kit (Red 6-Piston Dynapro, NA/NB) ↗Flyin' Miata· $1,359.00 USD
Front-Only FM Big Brake Kit (Red 4-Piston Dynapro, NA/NB) ↗Flyin' Miata· $1,239.00 USD - Stop Tech sport padsStop Tech
Fitted to the rear brakes
In the shops
Hawk HPS Street Rear Brake Pads D1002 (Miata Sport Suspension) ↗MiataSpeed· $157.99 USD
Wheels & Tyres 1
- Konig Hypergram wheels 15x8.5Konig
Fitted with 245/40/15 tyres
In the shops
Wheel, Hypergram, grey, 15x8, ET35, Konig ↗Moss Europe (UK)· £240.50 GBP
Wheel, Hypergram, grey, 15x8.5, ET35, Konig ↗Moss Europe (UK)· £256.25 GBP
Wheel, Hypergram, bronze, 15x8, ET35, Konig ↗Moss Europe (UK)· £256.25 GBP
Interior 1
- Mazda Roadster tall angled short shifterMazdaroadster.com
Installed with a Circuit Sport shift knob
In the shops
Fidanza 90-00 Mazda Miata Short Throw Shifter ↗MiataSpeed· $135.99 USD
CravenSpeed Short Throw Shifter (ND) ↗Flyin' Miata· $359.00 USDCravenspeed Short Throw Shifter (ND) ↗Flyin' Miata· $359.00 USD
Electrical 1
- CANCheck multi gaugeCANCheck
Installed to display AFR and boost without blocking A/C vents, with configurable pop-up alarms
In the shops
P3 V3 OBD2 Multi Function Gauge ↗
MazSpec MX-5 Spares & Accessories· £374.99 GBP
Haltech Multi-Function CAN Gauge ↗MiataSpeed· $426.00 USD
Tools & Workshop 1
- Equip 68 inch toolboxEquip
Traded in a Snap-on KRL722 for this larger toolbox
Photos
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How it was done
Starting condition
Mike bought the 2003 NB2 Turbo after his previous NA was totalled by another driver. The car had come from a chump-car racing background, stripped of interior, A/C and trim, and fitted with a prior owner's Flyin Miata GT2560 turbo kit, Voodoo Box management and basic suspension, but with sloppy workmanship including loose steering column bolts and a badly rigged oil drain.
Early failures
At its first autocross the car developed a serious oil leak from a cross-threaded turbo oil return fitting and began overheating. A planned quick reseal and clutch job turned into months at the shop. During initial start-up on the new Megasquirt system, a snapped camshaft dowel caused oil starvation damage to the exhaust cam journal, forcing a swap to a spare 1999 BP4W head.
Rebuild and upgrades
With the head swapped and engine resealed, Mike fitted ARP head studs, a Skunk2 intake and throttle body, CSF radiator, Supermiata coolant reroute, and relocated the ECU to the glovebox. He later installed Injector Dynamics 1050cc injectors and a Radium fuel rail, requiring some manifold clearance grinding, plus a DW255 fuel pump, Silvers coilovers, extended ball joints, and a Mazda Roadster short shifter.
Progress so far
By early January the car was running again with wheels and tyres mounted, fenders rolled, and a CANCheck gauge installed. A hardtop, trunk and bumper were being repainted, and Mike had booked a remote tuning session and tuning classes while continuing small fixes such as vacuum and boost leaks.
A summary in our own words. The full account, with all its detail, is in the original write-up: read it at Just another trubo NB2 ↗
Worth knowing
- Check that specialty injectors actually clear the intake manifold before assuming a spacer is missing
- Loose steering column pinch bolts and a makeshift turbo oil drain from a previous build can hide serious safety and reliability issues
- Inspecting an engine internally before use can reveal it is cleaner than its history suggests, but does not guarantee no hidden faults like a cam dowel failure