Complete in-house rebuild service for the HKS turbocharger lineup. Signature Series T51R Kai and T51R SPL, GT Series GT2530 through GT3240, GTII 7460 and 8262, and the current GTIII-RS, GTIII-4R, and GTIII-5R. In-house VSR balancing since 2008.
HKS produces turbochargers across four distinct families: the legacy Signature Series, the GT universal series, the GTII series, and the current GTIII series. All use MHI (Mitsubishi Heavy Industries) center cartridges.
The Signature Series uses Garrett-based architecture with HKS-designed compressor wheels, turbine wheels, and custom housings. The T51R series in particular is legendary: the distinctive recirculation channel in the compressor housing produces the characteristic T51R sound. All Signature Series units use V-band turbine inlet flanges. The T51R Kai and T51R SPL are discontinued, so parts availability should be confirmed before shipping.
The T51R Kai is the smaller of the two T51R variants. 70.3mm compressor inducer, 94mm exducer, 82mm turbine wheel. Rated to 800 PS on a built 2JZ or RB26. Available in journal bearing and ball bearing (BB) configurations, with the BB version spooling approximately 11% faster. V-band turbine inlet. HKS's proprietary recirculation channel in the compressor housing provides anti-surge function and produces the characteristic T51R induction sound. Discontinued and increasingly rare in any condition. Contact us before shipping to confirm parts availability.
The T51R SPL is the HKS flagship Signature Series turbo. 76.5mm compressor inducer, 102.2mm exducer. Same 82mm turbine wheel as the Kai but with the larger compressor raising peak flow capacity to 1,000 PS on a built 2JZ. Journal bearing and ball bearing configurations. V-band turbine inlet. The same proprietary recirculation housing design as the Kai, producing the T51R sound. Also discontinued. Extremely rare in new condition, so used examples of known history are the realistic rebuild option.
The smaller Signature Series units. The TO4S is rated to 550 HP and is the entry point of the HKS Signature Series. The T04R uses a 66.7mm / 84mm compressor wheel with a 74.2mm / 64.7mm turbine wheel and was used in HKS turbo kits on the 2JZ and RB26 platforms. Multiple turbine housing A/R options available (.81, .96, 1.00). Journal bearing. The T04R is a versatile unit on builds targeting 400-500 HP that want more spool than the larger T51R variants provide.
The GT Series uses MHI center cartridges with HKS-designed compressor and turbine housings. All GT series turbos are ball bearing. The model number encodes the compressor wheel size and turbine wheel diameter: GT2835 means approximately 28mm compressor class with a 35mm turbine class. These are among the most common HKS turbos seen in the market and all are fully supported at Boost Lab.
The GT2530 is used as a twin-turbo upgrade for the Nissan Skyline R32/R33/R34 GT-R RB26DETT in HKS's GTIII-2530 Sports Turbine Kit: a parallel twin-turbo setup with a lightweight compressor wheel designed for sharp low-RPM response where spool time matters as much as peak power. Used in matched pairs. Contact us before shipping if you are sending the twin-turbo set, since both units rebuild together.
The GT2835 is one of the most widely used HKS GT turbos in the market. Ball bearing, MHI center cartridge. Used in HKS GTS turbo kits for the Subaru Impreza WRX STI (EJ207), Nissan Silvia SR20DET, Mitsubishi EVO, and various other 4-cylinder platforms. The 56T trim compressor configuration is the most common. The GTIII-RS is the direct successor and is compatible with GT2835 installation positions with minor modification. Fully supported at Boost Lab.
The GT3037 is the step up from the GT2835, capable of supporting 400-500 HP on 4-cylinder platforms and used on larger displacement inline-6 builds where the GT2835 has been outgrown. The GT3037S is a revised variant with improved compressor characteristics. Both use MHI ball bearing center cartridges. The GTIII-RS directly succeeds the GT3037 family and shares most installation dimensions. GT3037 and GT3037S are both fully supported.
The GT3240 is the largest of the GT series universal turbos, capable of 500-600 HP on 2JZ and RB26 applications. Used by HKS on dedicated inline-6 builds where the GT3037 lacks the top-end flow needed. The GT3240 is not well-suited to small displacement 4-cylinder engines because the compressor map is sized for 2.5L-3.0L+ displacement. On the right platform it delivers strong power through the upper RPM range. Fully supported at Boost Lab.
The GT4094R sits at the top of the original GT Series: a large-frame unit for high-power 2JZ and RB26 builds targeting 600-800 HP. Less common than the GT3037 and GT3240 but fully supported. The GT4094R compressor map is sized for large displacement or highly modified engines running significant boost. Contact us with the unit to confirm parts availability and rebuild timeline.
The GTII series represents a significant step up in design from the original GT series: new MHI CHRA architecture, improved compressor housing aerodynamics, and enhanced ball bearing cartridge systems. All GTII units share the T25 turbine inlet flange and 4-bolt turbine outlet. The GTII 8262 was the top universal GTII unit before the GTIII series succeeded it.
The GTII 7460 is the smaller of the two main universal GTII units. 49T trim compressor, 0.69 A/R turbine housing. Compressor housing inlet 100mm, outlet 50mm. T25 turbine inlet flange, 4-bolt 65mm outlet flange. Water and oil cooled. Rated 340-450 HP. Compatible with GT2835 and GT3037 series installation positions, making the GTII 7460 a direct upgrade path from those earlier units. The GTIII-RS directly succeeds the 7460 with improved CHRA and better compressor efficiency.
The GTII 8262 is a step up from the 7460 with a larger compressor wheel while retaining the same T25 turbine inlet. Designed as an upgrade to the GTII 7460, so installation is direct with simple modification where required. Comparable in output potential to the GT3037S and GT3240 from the original series but with improved efficiency from the newer MHI CHRA design. The GTIII-RS also directly succeeds the 8262. Water and oil cooled. T25 inlet, 4-bolt 65mm outlet.
The GTIII Series is HKS's current-production universal turbocharger lineup. All GTIII units use the latest MHI high-performance CHRA, machined aluminum ported shroud compressor housings with anti-corrosion anodizing, and the inherited T51R-style recirculation channel for anti-surge. The GTIII-RS succeeds the GT2835, GT3037, GTII 7460, and 8262 family. The GTIII-4R and GTIII-5R succeed the TO4Z and T51R SPL respectively.
The GTIII-RS is the successor to the GTII 7460, GTII 8262, GT2835, and GT3037 series. MHI high-performance CHRA. Compatible with all of those prior units for direct installation with minor modification. T25 turbine inlet flange, 4-bolt 64mm outlet. Compressor housing inlet 100mm, outlet 49mm. Recommended range 340-480 HP. The machined ported shroud with anti-surge recirculation is standard, inheriting the T51R induction sound characteristic. Current production, so parts are available.
The GTIII-4R is positioned between the GTIII-RS and GTIII-5R: a step up from the RS for builds targeting over 500 HP. Successor to the TO4Z. Compact for its output class with MHI high-performance CHRA and forged aluminum impeller. Ported shroud function is selectable using an adapter to optimize for either anti-surge or maximum intake flow depending on application. Machined aluminum compressor housing with black anodizing and champagne gold ported shroud are the visual identifiers. Current production.
The GTIII-5R is the direct successor to the T51R SPL BB. MHI high-performance CHRA with forged aluminum impeller. Withstands over 800 PS. Oil and water cooled. Selectable ported shroud function via adapter. Designed as a drop-in replacement for T51R series turbos and kits: the oil and water inlet and outlet positions are matched for direct replacement of T51R installations. If you are considering upgrading from a T51R to a GTIII-5R, no kit modification is needed beyond what HKS specifies.
HKS uses a 14001-XXXXX format for their universal turbocharger part numbers. Vehicle-specific kit numbers follow a different format (11003-XXXXX and 11520-XXXXX). Search by HKS part number, model name, or application.
| HKS Part # | Model | HP Range | Application | Notes |
|---|---|---|---|---|
| T51R Signature Series | ||||
| 14001-AK014 | T51R SPL | 1,000 PS | Toyota Supra 2JZ-GTE / Nissan Skyline RB26DETT | Discontinued, confirm parts before shipping |
| 1401-RA145 | T51R SPL | 1,000 PS | Toyota Supra 2JZ-GTE / Nissan Skyline RB26DETT | T51R SPL alternate PN |
| 1401-RA146 | T51R SPL BB | 1,000 PS | Toyota Supra 2JZ-GTE / Nissan Skyline RB26DETT | Ball Bearing version |
| GT Series | ||||
| 14001-AK001 | GT2835 | 300-450 HP | Subaru EJ207 STI / Nissan SR20DET / EVO 4G63 / universal | MHI Ball Bearing |
| 14001-AK002 | GT2835 | 300-450 HP | Subaru EJ207 / Nissan SR20DET / universal | MHI Ball Bearing variant |
| 14001-AK003 | GT3037 | 400-500 HP | Universal T25 / inline-6 moderate builds | MHI Ball Bearing |
| 14001-AK004 | GT3037S | 400-500 HP | Universal T25 / 2JZ-GTE / RB26DETT mild builds | MHI Ball Bearing |
| 14001-AK005 | GT3240 | 500-600 HP | Toyota 2JZ-GTE / Nissan RB26DETT / large inline-6 | MHI Ball Bearing |
| GTII Series | ||||
| 14001-AK018 | GTII 7460 0.69 A/R | 340-450 HP | Universal T25 / SR20DET / EJ207 / 4G63 / 2JZ / RB26 | HKS MHI CHRA Ball Bearing |
| 14001-AK019 | GTII 7460 | 340-450 HP | Universal T25 / SR20DET / EJ207 / 4G63 | GTII 7460 variant |
| 14001-AK020 | GTII 8262 | 400-520 HP | Universal T25 / SR20DET / EJ / 4G63 / 2JZ / RB26 | HKS MHI CHRA Ball Bearing |
| 14001-AK021 | GTII 8262 | 400-520 HP | Universal T25 / inline-4 and inline-6 builds | GTII 8262 variant |
| 14001-AK027 | GTII 8267 (GT1000+ R35) | R35 GT-R only | Nissan R35 GT-R GT1000+ | Not Serviceable proprietary one-off |
| GTIII Series, Current Production | ||||
| 14001-AK031 | GTIII-5R A/R 1.00 WG | 800 PS+ | T51R SPL replacement / 2JZ-GTE / RB26DETT | Current Production, T51R drop-in |
| 14001-AK032 | GTIII-RS A/R 0.75 WG | 340-480 HP | GT2835 / GT3037 / GTII 7460 / 8262 replacement / universal T25 | Current Production |
| Vehicle-Specific Kits | ||||
| 11003-AN013 | GT1000 Full Turbine Kit | 1,000 HP R35 | Nissan R35 GT-R 2009+ | Not Serviceable proprietary one-off turbines |
| 14020-AN008 | GT1000+ Setup Kit | 1,000+ HP R35 | Nissan R35 GT-R 2009+ | Not Serviceable requires 14001-AK027 symmetry turbines |
| 11520-AN001 | GTIII-2530 Sports Turbine Kit | Twin for RB26 | Nissan Skyline R32/R33/R34 GT-R RB26DETT | Twin turbo kit, both turbos rebuilt together |
No results for your number? Contact us at sales@theboostlab.com with your HKS part number and we can confirm serviceability.
The T51R's proprietary recirculation channel, the feature responsible for the iconic T51R induction sound, has a separate seal system from a conventional compressor housing. The recirculation port can develop weeping oil if the seal at the recirculation channel deteriorates. This is often mistaken for a shaft seal failure. At teardown we distinguish between recirculation seal weeping and genuine shaft oil loss before quoting the rebuild. Most T51R oil loss at the compressor is the recirculation seal, not the primary shaft seal.
All HKS GT and GTII series turbos use ball bearing MHI center cartridges. Ball bearing turbos are sensitive to oil contamination and hot shutdown heat soak. Extended oil change intervals on Subaru EJ and Nissan SR20 engines, both of which are known for oil consumption and degradation under boost, accelerate ball bearing wear. The GT2835 and GTII 7460 are the most common HKS units we see with worn ball bearing cartridges from degraded oil. Ball bearing cartridge replacement is part of every GT and GTII rebuild where wear is found.
The T51R Kai and SPL are discontinued. Units in circulation have typically accumulated significant boost events over many years. The OEM compressor wheel on high-mileage or high-boost T51R units should be inspected for bore cracking at teardown. We check every T51R compressor wheel for stress fractures at the bore before assembling. Given the age of these units and the difficulty of sourcing genuine replacement wheels, any questionable wheel gets flagged before we proceed. Contact us before shipping so we can discuss inspection and replacement options upfront.
The GTII and GTIII series use machined aluminum compressor housings with anodized coatings. The ported shroud section in particular, which is a separate anodized insert on GTIII units, can develop surface corrosion if the coating is compromised by cleaning solvents, impact damage, or exposure to coolant from a failing head gasket (a common issue on EJ and SR20 platforms). Surface corrosion in the compressor housing affects both flow efficiency and the anti-surge function of the ported shroud. Housing condition is inspected at every GTII and GTIII teardown.
The GT2835 is extremely popular on Subaru EJ207 STI platforms. The EJ207 is notorious for oil consumption, particularly on modified engines running more aggressive cam timing and boost. Turbos on EJ207 engines frequently see oil that has thinned from combustion blowby contamination or extended intervals on degraded oil. The result is accelerated ball bearing wear that shows up as shaft play and vibration noise. Every GT2835 rebuild from an EJ207 application gets an oil system investigation recommendation.
The T51R series is water-cooled in addition to oil-cooled, which helps manage heat after shutdown. However, T51R turbos running very high boost levels on 2JZ and RB26 engines can still develop oil coking in the CHRA if coolant flow is marginal or if the coolant system has not been maintained. Coking restricts the oil passages inside the bearing housing, causing oil starvation on subsequent cold starts. Every T51R teardown includes internal passage inspection. Coolant line condition should be confirmed before a rebuilt T51R goes back on.
Start your rebuild request in our repair system. T51R through GTIII, all supported. Every job documented from intake through return with in-house VSR balancing.
Start Your Rebuild Request37833 Pineapple Ave Unit A • Dade City, FL 33523 • sales@theboostlab.com