HKS GTIII 2530 Turbo Kit Review: RB26 Skyline GT-R

The HKS GTIII 2530 turbo kit is one of the most respected forced-induction upgrades ever built for the Nissan Skyline GT-R and its legendary RB26DETT engine. Where the factory RB26 leaves the line at a conservative 276 hp (a figure everyone in the industry knows was capped by Japan's old gentlemen's agreement, with real dyno numbers closer to 310–330 hp), this HKS parallel-twin turbine kit rewrites the ceiling: up to roughly 600 PS (about 592 hp) on a properly built engine. In our Tampa, FL shop, RB26 builds are some of the most rewarding platforms we spec, and the GTIII 2530 sits right at the heart of the classic "500–600 horsepower Godzilla" recipe. Here is our full review, real specifications, fitment, and the supporting parts you need to run it safely.

What Is the HKS GTIII 2530 Sports Turbine Kit?

The HKS GTIII 2530 Sports Turbine Kit is a bolt-on parallel twin-turbo upgrade for the RB26DETT that replaces the factory ceramic-wheel turbochargers with two purpose-built HKS GTIII units. It keeps the RB26's signature parallel twin-turbo layout — one turbo feeding the front three cylinders, one feeding the rear three — so it drives like a factory GT-R, just with far more headroom. HKS designs the compressor wheels to spool in a linear, streetable way while unlocking the airflow needed for serious power. The kit ships preset at roughly 13 psi (0.9 kg/cm²) of boost and includes strengthened turbine actuators for stable boost control, plus upgraded oil-feed and water inlet/outlet lines to improve cooling and installation durability.

Because it bolts to the stock exhaust manifolds and reuses the OEM twin-turbo packaging, the GTIII 2530 is a genuine "turbine kit" rather than a full single-turbo conversion — the appeal for many Skyline owners is exactly that: big, reliable power without abandoning the RB26's character or drivability. It is not CARB approved and cannot ship to California; HKS lists it for off-road and competition use.

How Much Power Does the GTIII 2530 Make on an RB26?

The HKS GTIII 2530 supports up to roughly 600 PS (about 592 hp) on a built RB26DETT with proper fueling and tuning. On a healthy, otherwise-stock engine the kit typically targets a safer 330–400 PS window at its ~13 psi preset boost, which already represents a massive jump over the factory ~276–330 hp. The RB26 loves to rev, and the 2530's compressor sizing is tuned to keep pulling hard at the top of the tach where the engine is happiest — making it the natural choice for owners who want a big top-end hit rather than pure low-rpm response.

To be clear about the platform: a stock-internal RB26 will reliably live around 500 PS with good tuning and fueling, and the block is famously strong. To chase the full 600 PS and beyond with real durability, most builders add forged or billet rotating assembly parts — which is exactly where the supporting mods below come in. The turbos are the easy part; the fuel system, clutch, and tune are what turn the GTIII 2530 into a reliable street-and-track weapon.

GTIII 2530 vs GTIII-SS: Which RB26 Turbine Kit Is Right for You?

The choice between the GTIII 2530 and the smaller HKS GTIII-SS comes down to response versus top-end. The GTIII-SS is the near lag-free option: with wastegate spring pressure alone it will build around 7 psi by 3,000 rpm on an untuned RB26, so it feels almost like a factory turbo you can drive every day. The GTIII 2530 uses a slightly larger compressor that spools roughly 1,000 rpm later but rewards you with a bigger mid-to-top punch and a higher ceiling — up to 600 PS versus the SS kit's more modest target. If you daily your GT-R and value instant throttle, the SS is superb. If you want the classic big-power RB26 rush and plan to build the motor, the 2530 is the pick.

RB26 Build Sheet: What Pairs With the GTIII 2530

A turbine kit is only as good as the parts around it. Below is the core hardware we recommend to safely reach 500–600 PS on an RB26DETT alongside the GTIII 2530. The Manley Turbo Tuff billet crankshaft turns the 2.6L into a stroked 2.8L for a stronger, higher-ceiling bottom end; the HKS VCAM system broadens the powerband with variable intake cam timing; and Ohlins coilovers make sure the chassis can use the new power. Every item here fits the R32/R33/R34 GT-R and is in stock at NLP Performance.

Bottom End: Manley RB26DETT Stroker Crankshaft

To back up 600 PS with confidence, the Manley Turbo Tuff 77.7mm billet crankshaft is one of the best foundations you can lay. It is machined from premium 4340 billet with gun-drilled pins and fully knife-edged counterweights for reduced rotating weight and superior balance. A multi-step heat treatment plus nitriding maximizes durability, and every crank is stress-relieved, shot-peened, and 100% magnaflux inspected. The 77.7mm stroke bumps displacement toward the classic RB28 recipe, giving the GTIII 2530 turbos a bigger, torquier engine to breathe against.

Powerband: HKS RB26 VCAM System

The HKS RB26 VCAM Step 2 system adds continuously variable intake cam timing to the RB26 — technology the factory engine never had. By advancing and retarding the intake cam on the fly, VCAM fattens low-rpm torque, sharpens throttle response, and extends usable power up top, working hand-in-hand with the GTIII 2530's top-end character. It is a favorite on serious RB26 builds because it makes a big-turbo setup feel far more streetable without giving up peak output.

Chassis & Driveline: Ohlins Coilovers and a Stronger Clutch

Big power deserves a chassis that can put it down. The Ohlins Road & Track coilover system for the R33/R34 GT-R gives you race-derived damping with real street comfort, and it is the suspension we reach for on GT-R builds that see both canyon roads and track days. On the driveline side, the factory clutch is the weak link past ~400 PS, so a heavy-duty multi-plate clutch such as the Exedy Hyper Triple is a must to reliably hold GTIII 2530-level torque. Both are in stock and fit the classic Skyline GT-R.

Fitment: R32, R33 and R34 Skyline GT-R

The HKS GTIII 2530 Sports Turbine Kit fits every RB26DETT-powered Skyline GT-R across all three legendary generations: the R32 (BNR32, 1989–1994), the R33 (BCNR33, 1995–1998), and the R34 (BNR34, 1999–2002). Because it retains the factory parallel twin-turbo architecture and bolts to the OEM exhaust manifolds, installation is straightforward relative to a single-turbo conversion, though it is still a job for an experienced RB26 shop. Note that R34 engines came with ball-bearing turbochargers from the factory, while R32 and R33 units used less durable ceramic wheels — another reason the upgraded HKS billet-wheel turbos are a smart move on the earlier cars.

Pros and Cons of the HKS GTIII 2530