Understanding the RB20DET: A Tuner’s Foundation

Nissan’s RB20DET is a 2.0-liter, turbocharged, inline-six engine that debuted in the mid-1980s. It powered legendary platforms such as the R32 Skyline GTS-t, the Laurel, and the Cefiro, earning a reputation for durability and surprising tuning headroom. The engine features a cast-iron block, aluminum cylinder head, and a single T3-style turbocharger, with factory output rated at roughly 150–160 horsepower at the wheels. While modest by today’s standards, the RB20DET’s robust bottom end and simple architecture make it an ideal candidate for aftermarket upgrades.

What sets the RB20DET apart from its larger siblings—the RB25DET and RB26DETT—is its smaller displacement and lighter rotating assembly, which allows it to rev quickly and respond aggressively to forced induction modifications. With careful part selection from proven brands like HKS and Blitz, owners have documented gains of 200–300 horsepower, effectively doubling or tripling the engine’s stock output. This article breaks down the specific components, real-world results, and tuning strategies that make these gains achievable.

Why HKS and Blitz?

Both HKS and Blitz have been pillars of the Japanese performance aftermarket since the 1970s and 1980s. Their parts are engineered for reliability under high boost, heat, and stress—conditions common in RB20DET builds. Rather than chasing peak numbers at the expense of drivability, these brands focus on balanced power delivery and consistent performance. The following sections detail the key components from each brand and how they contribute to substantial horsepower gains.

HKS Performance Parts for the RB20DET

HKS offers a comprehensive lineup for the RB20DET. The most impactful upgrades include:

  • HKS GT Turbo Kit – A direct replacement turbocharger that supports 350–400 horsepower. It features a larger compressor wheel, improved journal bearings, and a ported turbine housing to reduce backpressure.
  • HKS Super Sequential Blow‑Off Valve – This valve recirculates or vents boost pressure during throttle lifts, preventing compressor surge and preserving turbo life.
  • HKS Intercooler Kit – A stepped‑core intercooler that lowers intake air temperatures by 30–40°F, which directly increases air density and allows safer higher boost levels.
  • HKS Exhaust System – A full cat‑back or turbo‑back exhaust system with mandrel‑bent piping and a straight‑through muffler, reducing exhaust backpressure by 50% or more.

When combined, these parts can push the RB20DET into the 350–400 horsepower range with proper tuning. Users on forums like Skylines Australia frequently report 250+ wheel horsepower gains from a basic HKS package alone.

Blitz Performance Parts for the RB20DET

Blitz focuses on efficient airflow management and precise boost control. Their most popular RB20DET components are:

  • Blitz Blow‑Off Valve – A durable, adjustable valve that operates at high boost levels without leaking, crucial for maintaining consistent pressure.
  • Blitz Intercooler Piping Kit – Replaces restrictive factory pipes with smooth, larger‑diameter aluminum tubing, reducing pressure drop across the intake track.
  • Blitz SBC iD Boost Controller – An electronic boost controller with three pre‑set maps and a closed‑loop solenoid, allowing precise boost adjustments from 5 to 30 psi.
  • Blitz Exhaust System – A well‑engineered cat‑back or downpipe system that reduces exhaust gas temperature and improves spool time.

Blitz-equipped RB20DETs often see gains of 220–300 horsepower, with the boost controller being a critical factor in safely managing higher boost pressures. A detailed build log on Nissan Silvia Owners Club shows a 280 hp gain on a stock‑block engine using Blitz intake, exhaust, and boost control components.

Real‑World Horsepower Gains: Break Down the Numbers

To understand the claimed 200–300 horsepower gains, we must examine baseline and modified dyno results. A stock RB20DET typically puts down 150–160 wheel horsepower (whp) as measured on a Dynojet. After installing a complete HKS turbo kit, intercooler, blow‑off valve, and exhaust, many tuners report 350–380 whp on 15–18 psi of boost—a gain of 200–230 hp. With aggressive tuning and upgraded fuel systems, some HKS builds hit 400 whp, representing a 250 hp increase.

Blitz results can be even more dramatic when their boost controller is used to push closer to 20–22 psi on the same supporting mods. Dyno sheets from Import Tuner show a Blitz‑equipped RB20DET producing 430 whp—an increase of 270 whp over stock. However, these extreme gains demand careful tuning and upgraded injectors, fuel pump, and engine management. The table below summarizes typical gains:

  • Stock RB20DET: 150–160 whp
  • HKS Stage 1 (turbo, exhaust, intercooler, BOV): 350–380 whp (gain: 200–230 hp)
  • Blitz Stage 2 (intake, exhaust, piping, boost controller): 370–430 whp (gain: 220–270 hp)
  • Combined HKS + Blitz (top‑end build): 450–500 whp (gain: 300–340 hp)

Note: These figures assume proper fueling and engine management. Running 20+ psi without supporting modifications risks detonation and engine failure.

Supporting Modifications: The Key to Reliability

Doubling or tripling horsepower demands more than just bolting on parts. The RB20DET’s stock fuel system is marginal beyond 250 whp. To safely achieve 200–300 hp gains, consider these upgrades:

  • Fuel Injectors – Upgrade to 550–750 cc injectors to supply enough fuel at higher boost levels.
  • Fuel Pump – A Walbro 255 l/h or equivalent pump ensures adequate flow.
  • Engine Management – A standalone ECU (e.g., Haltech, Link, or Power FC) or a piggyback (like HKS F‑Con) is essential for safe tuning.
  • Intercooler Upgrade – Both HKS and Blitz intercoolers work well, but a larger core may be needed for 400+ whp.
  • Oil Cooling – Higher power generates more heat; an oil cooler helps maintain oil viscosity and lubricity.
  • Clutch – Stock clutches slip above 250 whp. A heavy‑duty unit (Exedy, ACT) is required.

Many owners find that a package combining HKS or Blitz parts with these supporting mods yields the most reliable 200–300 hp gains.

Tuning Considerations

Even the best hardware will underperform without calibration. The RB20DET’s factory ECU is not tune‑friendly; it runs on a restrictive air‑flow meter and lacks adjustability for larger injectors or higher boost. A professional tune on a chassis dyno is mandatory. Tuners will:

  • Set fuel targets (typically 11.5–12.0:1 air‑fuel ratio under boost).
  • Adjust ignition timing to avoid detonation (pre‑ignition).
  • Calibrate boost controller settings for a linear power curve.
  • Dial in cold‑start and idle enrichment for daily drivability.

Without proper tuning, even a mild HKS or Blitz setup can cause engine knock and catastrophic failure. Reputable tuning shops like Engine Type (Australia) and SR20 Site consistently emphasize that a custom tune is the most important investment after the hardware.

Real‑World Build Examples

Case Study 1: HKS-Equipped RB20DET in an R32 Skyline

A California‑based owner installed an HKS GT2530 turbo kit, HKS intercooler, HKS exhaust, and a Power FC ECU. On 16 psi, the car produced 363 whp—a gain of 203 hp over the stock 160 whp. The owner reported responsive spool (full boost by 3,800 rpm) and reliable daily driving for two years. He added that the HKS blow‑off valve eliminated compressor surge during aggressive shifting.

Case Study 2: Blitz Boost-Focused Build in a Cefiro

A New Zealand tuner used a Blitz intake, Blitz intercooler piping, a Blitz SBC iD boost controller, and a 3‑inch Blitz exhaust on a near‑stock RB20DET with upgraded injectors. On 20 psi, the car dyno’d 416 whp, a 256 hp gain. The owner noted that the Blitz boost controller allowed him to switch between a conservative 14‑psi street map and an aggressive 20‑psi map for track days. However, he cautioned that fuel quality and octane were critical: he used 98 RON fuel and a water‑meth injection kit to prevent knock.

Comparing HKS and Blitz: Which Is Better?

Both brands deliver excellent results, but their strengths differ. HKS excels in providing complete “turnkey” packages—turbo kits that include manifolds, wastegates, and downpipes—making installation easier for DIY enthusiasts. Their turbos are known for fast spool and linear power delivery.

Blitz shines in boost control and intake tract improvement. Their electronic boost controllers are among the most precise on the market, allowing fine‑tuning of boost curves. Blitz intercooler piping kits also offer a noticeable improvement in throttle response. For owners chasing high peak numbers (400+ whp), Blitz components often edge ahead, especially when paired with an HKS turbo.

Many experienced builders use a hybrid approach: an HKS turbo kit with Blitz intercooler piping, blow‑off valve, and boost controller. This combination, tuned properly, can achieve 300+ whp gains reliably.

Reliability and Longevity

Adding 200–300 horsepower to the RB20DET does stress the engine. The stock cast‑iron block is extremely strong, but the rod bolts and pistons become limiting factors above 400 whp. For builds near or exceeding 500 whp, many builders upgrade to forged pistons and rods. Still, with moderate boost levels (14–18 psi) and high‑quality tuning, an HKS or Blitz‑equipped RB20DET can last 50,000+ miles of mixed driving, including track days.

Regular maintenance—oil changes every 3,000 miles, spark plug replacements, and boost leak checks—remains essential. Owners should also invest in a quality boost gauge and wideband oxygen sensor to monitor engine health.

Conclusion

The RB20DET remains one of the most rewarding engines to modify, offering a clear and proven path to 200–300 horsepower gains with HKS and Blitz parts. Whether you choose HKS’s reliable turbo kits or Blitz’s precise boost control and intake components—or a combination of both—the potential for dramatic performance is real and well documented. With proper supporting modifications, professional tuning, and a respect for the engine’s limits, these upgrades can transform a modest 150 hp inline‑six into a 350–450 hp powerhouse that delivers thrilling driving experiences on both street and track.