Overview of the Full-Race RSX Turbo Kit

The Full-Race RSX Turbo Kit has earned a reputation as a top-tier forced-induction system for the Honda RSX (DC5 chassis and K20 engines). Unlike generic universal kits, this system is engineered specifically for the RSX’s engine bay, suspension geometry, and drivetrain layout, ensuring straightforward fitment and optimal performance. The kit’s modular design allows owners to tailor the setup from a street-friendly 300 hp package to a track-capable 400+ hp monster. With proper tuning and supporting modifications, 350+ wheel horsepower is consistently achievable, transforming the RSX into a serious performer that can challenge far more expensive sports cars.

The foundation of the kit lies in its meticulous engineering. Full-Race uses mandrel-bent 304 stainless steel for all piping, cast stainless steel for the exhaust manifold, and billet aluminum for the compressor housing options. This level of quality reduces cracking, improves flow, and withstands the thermal extremes of high-boost operation. The kit is available in several turbo frame sizes, typically ranging from a Garrett GT3071R (for quick spool and 350 hp) up to a GT3582R or G25-550 (for 400+ hp with a broader power band). This scalability is a key advantage, allowing owners to start with a modest tune and later upgrade the turbocharger and fuel system without replacing the core piping.

Key Components and Their Roles

Turbocharger Options

The turbocharger is the heart of the system. Full-Race typically offers the following options for the RSX:

  • Garrett GT3071R – Excellent response, capable of 350–380 whp on pump gas. Ideal for daily driving and street use.
  • Garrett GT3582R – Up to 450 whp with larger injectors and E85. More lag but huge top-end power.
  • Garrett G25-550 – Modern ball-bearing design, spools faster than the GT3582R, supports 400+ whp.

Selecting the right turbo depends on your power goals, transmission strength, and willingness to accept lag. For a reliable 350 hp target, the GT3071R is the popular sweet spot.

Cast Stainless Steel Exhaust Manifold

The manifold is a critical piece: it must withstand extreme heat and direct exhaust gases smoothly into the turbine housing. Full-Race uses a cast stainless steel divided (twin-scroll) manifold that reduces reversion and improves spool time. The runners are equal-length to ensure even cylinder scavenging, which helps maintain a steady A/F ratio across all cylinders. This manifold also positions the turbo in a location that keeps the charge piping short and avoids interference with the alternator and steering shaft.

Air-to-Air Intercooler

The intercooler core measures approximately 12” x 12” x 3.5” and features a bar-and-plate design with cast end tanks. This configuration offers an excellent balance between pressure drop and thermal efficiency. The included piping routes directly from the compressor outlet to the throttle body, with a bead-rolled lip on all couplers to prevent blow-offs at high boost (over 25 psi). The intercooler is mounted in the front bumper crash bar location, requiring slight trimming of the plastic bumper cover but retaining full functionality of the A/C condenser and radiator.

Blow-Off Valve / Bypass Valve

The kit includes a Tial Q or Turbosmart blow-off valve (depending on the current iteration). This component protects the turbocharger compressor wheel from surge when the throttle closes abruptly. The blow-off valve is vented to atmosphere, producing the classic “whoosh” sound, but the ECU must be tuned to account for the metered air being released (a common issue with MAF-based ECUs). Full-Race provides a recirculation option for those who prefer a quieter setup and easier tuning.

Fuel System Upgrades

To achieve 350+ hp, the stock RSX fuel system is insufficient. The kit includes either 550cc or 750cc injectors (depending on the power target) and a high-flow fuel pump (typically a Walbro 255 lph or a DW300). These components ensure enough fuel volume and pressure under high boost. If using E85, larger injectors (1000cc+) and a fuel return system are recommended. The fuel lines included are PTFE-lined for Ethanol compatibility.

Installation Considerations

Installing the Full-Race RSX Turbo Kit is an advanced job requiring mechanical experience and specialized tools. Expect to spend 8–15 hours in a home garage, less if the car is on a lift. Key steps include:

  • Removing the front bumper, radiator, and A/C condenser (reinstall required).
  • Draining coolant and oil.
  • Removing the stock exhaust manifold, downpipe, and intake.
  • Installing the turbo manifold and turbo assembly onto the studs; using thread locker on all nuts to prevent loosening from vibration.
  • Routing oil feed and drain lines; the drain must slope continuously downward to avoid oil coking in the turbo center section.
  • Mounting the intercooler and routing charge pipes, securing with silicone couplers and T-bolt clamps.
  • Installing the downpipe (must clear the subframe; Full-Race provides a flex joint to reduce strain).
  • Connecting vacuum lines for wastegate and blow-off valve.
  • Installing injectors and fuel pump (may require dropping the fuel tank).
  • Reassembling the front end and connecting the ECU for tuning.

Common pitfalls include inadequate clearance between the downpipe and the steering shaft (some minor adjustment may be needed) and routing the oil drain without kinks. If you are not comfortable with wiring or fuel system work, consult a professional shop – safety and reliability depend on proper installation.

Tuning for Maximum Power

After mechanical installation, tuning is the single most influential factor in achieving 350+ hp. The stock RSX ECU (with K-Pro or K-Tuner) can be reflashed for boost, but a standalone ECU like a Hondata S300, MoTeC M1, or a Haltech Elite 2500 offers more precise control and datalogging capability. Many Full-Race users favor Haltech or Hondata because of the extensive community support and plug-and-play harnesses.

ECU Tuning Parameters

A professional tuner will adjust the following:

  • Fuel maps: Adding fuel under boost to maintain a safe Air/Fuel Ratio (typically 11.5–12.0:1 for pump gas, richer for E85).
  • Ignition timing: Retarding timing as boost increases to prevent knock. Expect timing of 15–20° at peak boost on pump gas; more aggressive on ethanol.
  • Boost control: Using an electronic boost controller to set boost levels per gear and rpm, preventing wheel spin and reducing drivetrain stress.
  • VTEC engagement: Adjusted to match the turbo’s power band – often moved higher than stock to help the engine rev cleanly into high rpm.
  • Temporary overboost control: Fuel cut or boost cut to protect the engine if wastegate control fails.

Because the RSX’s K20 engine has a relatively high compression ratio (11.0:1), careful attention to knock detection is needed. A wideband oxygen sensor and knock sensor should be monitored in real time during dyno tuning.

Dyno Tuning Process

Once the car is on a chassis dynamometer, the tuner will perform several pulls, gradually increasing boost from wastegate spring pressure (typically 5–7 psi) up to the target pressure (10–15 psi for 350 hp). Pull after pull, the tuner adjusts fuel and ignition maps until the A/F ratio and power curve are smooth and safe. Expect to pay $400–$800 for a full dyno tune, depending on the shop and hourly rates. A reputable tuner will provide a printout of the final power numbers and A/F ratio across the rpm range.

For 350+ whp, typical boost levels are around 12–15 psi on 93 octane pump gas. If using E85, boost can be increased to 16–18 psi with less timing retard, yielding up to 400 whp on the same turbo. A proper tune will also account for variations in altitude and ambient temperature – a good tuner will include some safety margins.

Supporting Modifications for Reliability

While the Full-Race kit includes the essential parts for boosting, several supporting upgrades are strongly recommended to ensure the engine survives and thrives at 350+ hp:

  • Clutch upgrade: The stock clutch slips above 280 whp. A stage 2 or stage 3 clutch (e.g., ACT or Exedy) is necessary. Choose a sprung hub disc for smoother daily driving.
  • Exhaust system: The kit’s downpipe terminates with a 3” flange; a full 3” cat-back exhaust is needed to reduce back pressure. Keep the catalytic converter for street legality, or go test pipe for max flow (check local emissions laws).
  • Engine mounts: Stiffer bushings (Hasport, Innovative) prevent the engine from twisting under load, reducing drive-ability issues and potential exhaust leaks.
  • Cooling system: A larger radiator (e.g., Koyo or CSF) and possibly an oil cooler help manage heat. RSX engines run hot under boost, especially in summer track days.
  • Brake upgrade: Stopping a car making 350+ hp requires better brakes – at least upgraded pads and rotors, if not a BBK (big brake kit).

Expected Power Gains and Real-World Dyno Results

The following table summarizes typical results from multiple Full-Race RSX Turbo Kit builds:

Configuration Fuel Boost (psi) Wheel Horsepower
GT3071R, stock block, 550cc injectors 93 octane 12 340–360 whp
GT3071R, upgraded cams, 750cc injectors E85 16 380–400 whp
GT3582R, built block, 1000cc injectors E85 18 440–460 whp

Note: Wheel horsepower figures vary based on dyno type (Dynojet reads higher than Mustang), altitude, and ambient conditions. A conservative tune on a Dynojet often reads 5–10% higher than a Mustang dyno. The numbers above are representative of well-built, properly tuned examples.

Reliability and Maintenance

When built and tuned correctly, the Full-Race RSX kit exhibits excellent reliability. The factory K20A2 block can handle 350 whp on pump gas without internal upgrades, provided it is not subjected to extreme detonation. However, daily-driven cars at this power level require strict maintenance:

  • Change engine oil every 3,000 miles (use a high-quality synthetic 5W-30).
  • Inspect turbo oil return line for leaks at every oil change.
  • Check all charge pipe clamps for tightness – loose clamps cause boost leaks and erratic AFRs.
  • Monitor catch can (if installed) for oil blow-by; excessive blow-by indicates ring wear.
  • Use a boost controller with a failsafe mode (mechanical or digital) to protect against wastegate failure.
  • Replace spark plugs with a colder heat range (e.g., NGK BKR7EIX) gapped to 0.028” under boost.

Many owners report daily driving their 350+ whp RSX for 30,000+ miles with no major issues when they adhere to these practices. Track-driven cars may need stronger connecting rods (e.g., Eagle or K1 rods) if exceeding 400 whp.

Cost Breakdown

The Full-Race RSX Turbo Kit itself retails for approximately $3,200–$4,000 depending on the turbo option. However, the total cost of a 350+ hp build extends beyond the kit:

  • Full-Race RSX turbo kit: $3,200–$4,000
  • Fuel system (injectors + pump): $500–$700
  • Clutch: $400–$800
  • Exhaust (downpipe to cat-back): $600–$1,200
  • Engine mounts: $250–$500
  • Radiator/oil cooler: $400–$800
  • ECU tuning (K-Pro or Haltech): $500–$1,500
  • Professional installation (if not DIY): $1,000–$2,000
  • Dyno tuning: $400–$800

Total investment: approximately $7,000–$11,000+ for a reliable 350+ hp RSX. While that may sound high, the result is a car that can outperform a new Civic Type R or many German turbo coupes at a fraction of the cost.

Comparison with Other RSX Turbo Kits

The Full-Race kit competes with offerings from GReddy, Garrett by SPOOLIN, and Rev9 (budget). Here’s how it stacks up:

  • Build quality: Full-Race uses 304 stainless and cast iron vs. GReddy’s budget cast manifold (prone to cracking). Rev9 kits require significant modification to fit and often have poor welding.
  • Support: Full-Race provides excellent customer support, detailed instructions, and phone assistance. Many owners recommend buying directly or from authorized dealers like Full-Race.com.
  • Performance: Full-Race out-of-the-box designs flow better, enabling higher horsepower with less boost than cheaper kits. The twin-scroll manifold provides faster spool than single-scroll alternatives.
  • Long-term value: Higher initial cost pays off in reliability – fewer failures, less time troubleshooting, and better resale value.

For those on a strict budget, a used Full-Race kit often offers better long-term value than a new budget kit due to the superior build quality.

Final Thoughts

Achieving 350+ horsepower with the Full-Race RSX Turbo Kit is not just a marketing claim – it is a repeatable, documented outcome when the kit is combined with proper supporting modifications and professional tuning. The key is to resist cutting corners on fuel system, clutch, and engine management. Every weak link will be exposed at 350+ whp. For RSX owners who want a fast, reliable, and enjoyable street car or weekend track toy, this kit is one of the best investments you can make.

Before starting a build, spend time on forums such as Club RSX and Hondata to learn from others’ experiences. Source the kit from a reputable vendor, and never compromise on the quality of the tune. With the right approach, your RSX can become a reliable 350+ hp machine that delivers thrills for years to come.