The Starion and its Chrysler Conquest twin ran Mitsubishi's own TD05 turbo family on the 2.6L G54B, and Mitsubishi walked away from parts support when production ended in 1989. Boost Lab, Inc. rebuilds the whole line: the early flat-fender TD05H-12A under 49178-01600, the later 12A revisions, and the intercooled widebody TD05H-16G on the 1987 to 1989 ESI-R and TSi. We also service the 16G through 20G upgrade hybrids these cars commonly wear. Nationwide ship-in service.
Three factory turbo configurations across the production run, plus the upgrade culture that followed. Identify yours by the tag, not the fender.
The early narrow-body cars ran the TD05H-12A under 49178-01600, Mitsubishi MD112706, with the early flatback compressor wheel. Non-intercooled at first, these are the simplest Starquest turbos and among the most age-worn cores we see: forty years of heat cycles on original bearings and seals.
Later 12A service units carry 49178-01730 and -01740 with the 40/54mm 12A wheel on the standard TD05 56.4/47.4mm turbine. Note the trap: 49178-01750 and -01760 look similar but use the larger TD05H turbine wheel, and cartridge parts do not interchange. The tag decides everything.
The intercooled widebody cars stepped up to the TD05H-16G, the same 16G designation that later became famous under DSMs. 176-188 hp with the intercooler and the strongest factory Starquest configuration. Cores rebuild readily and 16G wheel parts remain in production thanks to the DSM world.
The Starquest's TD05/TD05H frame is one of the most supported turbo architectures ever made, serving DSMs, EVOs and Subarus for decades after. Bearings, seals, thrust parts, and wheels all remain available, which makes the Starquest one of the best-supported orphan platforms in the hobby.
Half the running Starquests wear an upgraded compressor: Big 16G, 18G and 20G hybrids on the stock frame are community standards. We rebuild them all, balance every assembly, and can build your 12A core into a 16G-class hybrid during the rebuild if that is the direction you want.
The 2.6L G54B is torquey, under-square, and hard on oil when neglected, and the turbo lives downstream of those oil habits. Jet-valve-era oiling quirks and long intervals show up as coked centers and worn journals on the bench. Fresh oil habits protect the rebuild.
The Starquest 12A family hides a trap. Units tagged 49178-01730 and -01740 run the standard TD05 turbine; units tagged 49178-01750 and -01760 run the larger TD05H turbine wheel, and cartridges, kits and wheels do not interchange between them despite identical-looking housings. Buying parts by model name instead of tag number is how Starquest rebuilds go wrong. Photograph your tag and send it through the repair form before ordering anything, from us or anyone else.
Verified Mitsubishi Heavy Industries numbers for the Starion and Conquest. Search by any number.
| Turbo PN | Model | OEM PN | Application | Notes |
|---|---|---|---|---|
| 49178-01600 | MHI TD05H-12A | Mitsubishi MD112706 | 1983-1986 flat-fender Starion / Conquest 2.6 | Early flatback compressor wheel |
| 49178-81100 | MHI TD05-12A | Verify by tag | Flat-fender era service unit | Flatback wheel variant |
| 49178-01730 / 49178-01740 | MHI TD05-12A | Verify by tag | Later 12A service units, G54B 2.6 | Standard TD05 turbine (56.4/47.4mm) |
| 49178-01750 / 49178-01760 | MHI TD05H (larger turbine) | Verify by tag | 12A-family units with TD05H turbine wheel | Does NOT share cartridge parts with -01730/-01740 |
| Tag-specific | MHI TD05H-16G | Verify by tag | 1987-1989 widebody Starion ESI-R, Conquest TSi | Intercooled cars; DSM-shared 16G wheel family |
| Tag-specific | Big 16G / 18G / 20G hybrids | n/a (upgrade) | Community upgrade builds on the TD05 frame | Rebuilt and balanced; conversion builds available |
| 405-02013-006 class | 12A compressor wheel | n/a | TD05H-12A service | Fits 49178-01600 / -01700 / -01710 / -01740 units |
Forty-year-old cores from an orphaned platform: the patterns are consistent.
Every factory Starquest turbo is now 36 to 43 years old, and most have never been apart. Shaft play, whine, and oil consumption are the default presentation. Caught before the wheels contact the housings, these simple journal-bearing units rebuild to better than new.
The G54B era predates synthetic oil culture, and long intervals plus hot shutdowns coked center sections for decades. We clean CHRA passages to bare metal on every Starquest rebuild, and modern oil plus a 30-second idle-down habit keeps the fresh bearings alive.
Starquests sit. Storage hardens the seals, and the first hard pull of the season pushes oil into the exhaust and intercooler plumbing. Startup smoke that clears is the classic sign; the core underneath is usually fine.
We regularly open 12A units carrying mismatched cartridge parts from the -01730 versus -01750 turbine confusion: wrong wheels, wrong clearances, assemblies that were never balanced. The tag governs. We put them right and balance every assembly.
The Starquest community has been winding up boost since the 80s. Overworked thrust bearings let the compressor wheel walk, and tired wastegate hardware causes creep that gets blamed on the cartridge. Uprated thrust parts and actuator setting are standard on our performance rebuilds.
Decades of heat cycling checks the turbine housing surface. Light checking is normal and serviceable; through-cracks need housing work, and the TD05's massive parts ecosystem means good housings remain findable.
Yes, and better than for almost any other orphan car. The TD05/TD05H architecture lived on under DSMs, EVOs and Subarus, so bearings, seals, thrust parts and wheels remain in production. Your original casting is the only scarce piece.
US-spec 1987-1989 widebody cars, Starion ESI-R and Conquest TSi, run the TD05H-16G with the intercooler. Earlier flat-fender cars run the TD05H-12A family. The compressor housing tag confirms it; send photos if the car's history is unclear.
Because 49178-01730/-01740 and 49178-01750/-01760 look identical but run different turbine wheels, and cartridge parts do not interchange. Order by tag number, never by '12A' alone.
Yes. The TD05 frame accepts the larger wheel families, and a Big 16G-class hybrid on your original housings is a proven Starquest combination. Tell us your power goal in the submission and we will spec it honestly.
Likely just seals hardened by storage, the most common Starquest complaint. A reseal with modern materials plus a bearing inspection usually returns a unit healthier than it has been in decades.
Start at repair.theboostlab.com, photograph the tag first, drain the oil passages, cap the openings, and double-box. Ship to Boost Lab, Inc., 37833 Pineapple Ave, Unit A, Dade City, FL 33523.