Why 300–400 Horsepower Is the Sweet Spot for Your Acura RSX

The Acura RSX, especially the Type-S with its K20A2 or K20Z1 engine, is one of the most popular platforms for affordable performance. With a well-chosen turbo kit, you can reliably push 300–400 wheel horsepower without sacrificing daily drivability. That power band keeps the stock block safe, allows for a conservative tune, and still gives you enough grunt to surprise cars costing twice as much. In 2024, the aftermarket offers several mature, bolt-on kits that make this goal achievable for a dedicated DIY builder or a shop-installed project.

Below we break down the top five RSX turbo kits that deliver in that 300–400 hp range. Each kit has its own philosophy—some prioritize off-the-shelf reliability, others lean into tunability, and a few focus on all-out build quality. We’ve included pricing, component highlights, and real-world considerations so you can pick the setup that matches your budget and skill level.

1. Greddy Turbo Kit – The Reliable All-Rounder

Greddy (Trust) has been a staple in the Japanese performance world for decades. Their RSX turbo kit is one of the most proven, with thousands of street cars and track builds using it over the years. The kit is designed to be a complete, bolt-on solution that does not require custom fabrication—ideal if you want a straightforward install and predictable results.

Key Components & Specifications

  • Turbocharger: Greddy T518Z or T62-1 (depending on revision). Both are journal-bearing units with fast spool characteristics well-suited to the K20’s displacement.
  • Intercooler: Bar-and-plate core, rated for up to the 400 hp mark. Mounting brackets and piping are included.
  • Wastegate & Blow‑Off Valve: Greddy Type-R or Type-S BOV included; the wastegate is a 38mm unit (or integral in some versions).
  • Manifold: Cast iron or stainless steel log manifold (model dependent). Cast manifolds reduce heat soak but can be heavier.
  • Piping & Hardware: Powder-coated charge pipes, couplers, clamps, oil lines, and all necessary bolts.
  • Fuel System Add‑Ons: Many Greddy kits do not include fuel injectors or a fuel pump—budget for at least 550cc injectors and a Walbro 255 lph pump.

Power Output & Tuning

The Greddy kit is capable of up to 400 hp on a well-tuned setup with proper fuel upgrades. Most owners report 320–360 whp on the stock K20A2 with a conservative tune (around 8–10 psi). If you push closer to 400 whp, you should consider ARP head studs and a stronger clutch. The kit is compatible with Hondata K‑Pro, FlashPro, or even a piggyback like the AEM F/IC for basic control.

Installation Notes

Installation is very straightforward compared to other kits. The Greddy kit is engineered as a “complete kit”—no cutting, no welding. The charge piping routes cleanly, and the intercooler sits behind the factory bumper beam. Expect a weekend install if you have moderate mechanical experience. Be mindful that the supplied oil feed and drain lines may need slight bending; test fit everything before final tightening.

Pricing & Value

Approximate price: $3,800–$4,200 depending on the vendor version (some include a Greddy e-Manage piggyback, others do not). Since it lacks injectors and a pump, add $400–$600 for those parts. Tuning will run another $400–$800 if you cannot self-tune. All-in, the Greddy route is a solid mid-range investment that has legendary support in the RSX community.

Pros

  • Proven reliability with thousands of street miles documented on forums like ClubRSX and RSX Owners.
  • Excellent spool characteristics – full boost by 3800–4200 rpm.
  • Complete bolt-on design, minimal fabrication required.
  • Strong aftermarket support (Greddy is widely available, parts easy to source).

Cons

  • Log-style manifold limits top‑end flow compared to equal-length tubular manifolds (like Full-Race).
  • Outdated turbo technology (journal bearing, not ball bearing). Upgrade options require custom downpipe modifications.
  • Not the best choice if you plan to exceed 400 hp – the cast manifold becomes a bottleneck above 450 whp.

Check Greddy’s official RSX turbo kit page →

2. Hondata K‑Pro Turbo Kit – The Tuner’s Choice

Strictly speaking, Hondata does not sell a full turbo kit with a manifold and turbocharger. Instead, their “K‑Pro Turbo Kit” refers to the bundle they market alongside their flagship ECU solution – the Hondata K‑Pro engine management paired with a selection of recommended components (manifold, turbo, injectors, etc.) that you assemble yourself. This approach appeals to enthusiasts who want complete control over the final configuration.

What the Kit Includes

  • Hondata K‑Pro ECU (PND or PRB version) – the heart of the setup, offering full fuel, ignition, VTEC, and boost control tables.
  • Base accessories: A Hondata intake manifold gasket, boost harness, and sometimes a 3‑bar MAP sensor.
  • Recommended component list: Most vendors bundle the K‑Pro with a Garrett GT3071R or BorgWarner S200SX turbo, a Precision or Treadstone intercooler, a custom downpipe, and 750cc+ injectors. You choose the manifold—many go with an equal-length tubular unit from Full-Race or a budget ramhorn manifold.

Power Output

Because this kit is built from your chosen components, the power potential is wide open. With a Garrett GT3071R and good manifold, 300–350 whp is achievable on pump gas at 10–12 psi. Push to 18–20 psi with ethanol and you can hit 450 whp, but that requires internal engine modifications (rods, pistons). The 300–350 hp range is safe on a stock K20A2 with ARP studs and a good tune.

Why Tuners Love It

Hondata K‑Pro is the gold standard for K‑series tuning. The ability to alter VTEC engagement, cam phasing, and boost targeting gives you unmatched flexibility. The kit is really a platform, not a fixed part list – you can start with a modest setup and upgrade components over time without changing the ECU.

Installation & Tuning Notes

Installation is more involved than a complete kit because you are sourcing the turbo, manifold, intercooler, and piping separately. You will need to fabricate or purchase a downpipe and charge piping. However, many online vendors (like Hondata directly or Acura performance shops) offer “K‑Pro kit” bundles that include all the necessary pieces – you just assemble and tune. Expect a more hands-on weekend, or pay a shop for custom piping (around $800–$1,200).

Pricing

The K‑Pro ECU itself retails for about $1,100. A complete bundle with turbo, intercooler, manifold, injectors, and fuel pump runs $3,500–$4,500 depending on component quality. This is competitive with Greddy, but you get a much more capable ECU and modularity for future upgrades.

Pros

  • Best engine management in the K‑series world – full user control, data logging, real-time tuning.
  • Build-your-own approach means you can choose exactly the turbo and manifold for your goals.
  • Easier to upgrade later (swap turbo, change injectors, re-tune).
  • Huge community and tuning support (hundreds of K‑Pro base maps available).

Cons

  • Not a turnkey solution – requires more planning and sourcing.
  • Total cost can escalate if you choose premium components.
  • If you are not a tuner, you must factor in professional tuning costs.

Learn about Hondata K‑Pro for RSX →

3. AEM Turbo Kit – Precision Engineering with Strong Support

AEM (Advanced Engine Management) has been a competitor to Greddy in the “complete bolt-on” space for many years. Their RSX turbo kit is built around a precision ball‑bearing turbocharger (often a BorgWarner EFR unit in later versions) and a high-efficiency bar-and-plate intercooler. AEM focuses on power consistency and component durability, making this kit a favorite for daily drivers who occasionally track their car.

Key Features

  • Turbo: BorgWarner EFR 6258 (or equivalent). Ball‑bearing center cartridge for lightning-fast spool and reduced lag.
  • Manifold: T4 divided stainless steel tubular manifold with equal-length runners. This design greatly improves exhaust scavenging compared to log manifolds.
  • Intercooler: AEM-specific 22”×12”×3” core with cast end tanks. Rated at over 500 hp – lots of headroom.
  • Wastegate: Tial 38mm MVR (included and pre‑mounted to the manifold).
  • Blow‑Off Valve: AEM adjustable BOV included.
  • Piping: Mandrel-bent 2.5” charge pipes with T‑bolt clamps. All couplers are silicone and reinforced.
  • Fuel System: AEM 320 lph fuel pump and 625cc injectors are included with the “complete” version of the kit. Some retailers sell a “basic” kit without these – verify before ordering.
  • Tuning Support: AEM provides base maps for their own AEM F/IC6 or Infinity ECU. You can also use K‑Pro if you prefer.

Power Output

On the RSX Type-S, the AEM kit reliably produces up to 400 hp at the wheels with the included injectors and a safe tune (around 11 psi). The ball‑bearing turbo spools significantly faster than the journal‑bearing Greddy – expect full boost by 3500 rpm. This makes the car very responsive in daily driving, with strong mid-range torque.

Installation Experience

Installation is similar to Greddy in terms of completeness. The manifold and downpipe are designed to bolt up to the stock engine mounts and exhaust system (though the downpipe neck-down to 2.5” can slightly restrict top-end power – many owners upgrade to a full 3” exhaust). The intercooler piping routes neatly behind the bumper; you do not need to cut the crash bar. The kit includes detailed instructions. Most DIY mechanics can finish in 12–15 hours.

Pricing

The AEM RSX turbo kit typically retails for $4,200–$4,600 depending on whether you buy the “stage 1” (without fuel system) or “stage 2” (with fuel upgrades). Considering the ball‑bearing turbo, Tial wastegate, and tubular manifold, this is a premium kit that justifies its cost with parts quality.

Pros

  • Exceptional turbo spool – near‑instant throttle response.
  • Tubular manifold provides superior flow and power potential (good for future upgrades beyond 400 hp).
  • Complete kit with fuel system included in most packages.
  • Strong build quality – every bracket and hose is custom‑made for the RSX.

Cons

  • Price is on the high side; some users find the Greddy kit sufficient for 300 hp at a lower cost.
  • The AEM F/IC6 piggyback is less capable than K‑Pro – if you already have Hondata, you may not need the F/IC.
  • Minor fitment issues have been reported with aftermarket cold‑air intakes (battery relocation may be needed).

View AEM’s official RSX turbo kit →

4. Full‑Race Turbo Kit – Maximum Build Quality and Performance

Full‑Race Motorsports is known for high-end fabricated components, especially their tubular exhaust manifolds. They offer a complete RSX turbo kit that is arguably the best on the market for those who want the absolute highest quality piping and the ability to exceed 400 hp reliably. The kit is engineered as a “built engine” solution, but it works fine on a stock block if you keep boost moderate.

What You Get

  • Manifold: Full‑Race signature cast-steel “Ramhorn” manifold with divided T4 or T3 flange. This design is virtually crack‑proof and provides excellent flow distribution. It flows well over 700 hp, leaving plenty of headroom.
  • Turbocharger: The kit is typically sold with a Garrett GTX3076R Gen2 (ball‑bearing). However, Full‑Race offers custom turbo options (EFR, GTW, etc.) at additional cost.
  • Wastegate: Tial 44mm MVR (external) – heavy‑duty, pro‑level wastegate.
  • Intercooler: Garrett or Treadstone core (Full‑Race branded) – large 24”×12”×3” core with 3” inlet/outlet.
  • Downpipe: 3” mandrel‑bent stainless steel downpipe with V‑band connections. Supports high flow and easy removal.
  • Piping & Coupers: 2.5” or 3” aluminum charge pipes with silicon couplers from Vibrant Performance.
  • Fuel System: Includes 1000cc injectors (Bosch EV14), fuel rail, and a Walbro 450 lph pump.
  • Engine Management: The kit does not include an ECU – you are expected to use K‑Pro, MoTeC, or Haltech.

Power Output

The Full‑Race kit is designed for 350–400+ hp on a stock block with a conservative tune. The GTX3076R Gen2 can easily support 550+ whp on a built motor. At 400 whp, you are operating well within the turbo’s efficiency range, resulting in low intake temps and steady boost control. On pump gas (93 octane) at 12 psi, expect 370–390 whp. With E85 and 18–20 psi, you can cross 500 whp – but that requires forged rods and pistons.

Build and Installation

Full‑Race kits are known for “show‑quality” fabrication. The manifold is tig‑welded, the downpipe is handcrafted, and every bracket is powder‑coated. Installation is more involved than other kits because of the large intercooler and the need to relocate the battery (to the trunk) on many RSX models. The downpipe clearance is tight; you may need to trim the subframe braces slightly. This is not a beginner’s kit – plan a full week of work if doing it yourself, or budget $1,500–$2,000 for professional installation.

Pricing

This is the most expensive kit in our list. The complete Full‑Race RSX turbo kit (with all fuel system components) retails for $5,500–$6,500 depending on turbo choice and options. The base level (less turbo and intercooler) is around $4,000, but by the time you add a Garrett blower and a large intercooler, you’re at the premium price point.

Pros

  • Unmatched build quality – the manifold and downpipe are work of art.
  • True plug‑and‑play for 500+ hp builds; you can grow into the kit.
  • Excellent customer support from Full‑Race (they help with tuning advice and specific questions).
  • Resale value remains high because of the brand reputation.

Cons

  • Overkill for someone targeting only 300–350 hp – you are paying for headroom you may never use.
  • Installation is complex and may require battery relocation and subframe modifications.
  • Not a budget option – likely twice the cost of a Greddy kit.

Explore Full‑Race’s RSX turbo kits →

5. Precision Turbo Kit – Budget‑Friendly Without Sacrificing Reliability

Precision Turbo & Engine (formerly Precision PT) offers a turbo kit that targets the enthusiast on a tighter budget. While Precision is famous for their high‑power turbochargers (like the 6262, 6466, etc.), their RSX kit uses a more modest PT5266 or PT5862 turbo, which provides excellent response and the ability to hit 350 hp without stressing the factory engine internals.

Kit Contents

  • Turbo: Precision PT5266 or PT5862 (journal bearing, but Precision’s proprietary ball‑bearing option is available as an upgrade).
  • Manifold: Cast iron T3 log manifold – simple and durable, but not as free‑flowing as tubular designs.
  • Intercooler: Precision 21”×11”×3” bar‑and‑plate core with cast end tanks.
  • Wastegate: Tial 38mm MVR (included).
  • Blow‑Off Valve: Tial Q (included).
  • Piping: Mandrel‑bent 2.5” charge pipes with silicone couplers.
  • Fuel System: The basic kit does not include injectors or pump – budget for 550cc injectors and a 255 lph pump.
  • EMS: No ECU – you will need K‑Pro or a standalone.

Power Output & Tuning

The Precision kit is rated for up to 350 whp safely on a stock RSX motor with proper fuel and tuning. The PT5262 turbo spools quickly (full boost by 4000 rpm) and holds boost well. Many owners report 330–340 whp on 9 psi with 93 octane. If you upgrade to the ball‑bearing center section and add a 3‑bar MAP sensor, you can push towards 400 whp, but the small turbine housing becomes restrictive above that.

Installation Notes

Installation is comparable to the Greddy kit – relatively simple for a weekend. The log manifold simplifies piping layout. The intercooler fits behind the stock bumper with minimal trimming. The only tricky part is routing the oil drain line; use the supplied stainless braided line and ensure no kinks. The kit is designed to work with the stock AC and power steering – a big plus for daily‑driven cars.

Pricing

This is the most affordable complete kit in our roundup, retailing for $2,800–$3,200 depending on whether you get the ball‑bearing upgrade. Even after adding injectors ($250), pump ($120), and tuning ($500), you are still under $4,000 total. For the budget‑conscious RSX owner, this is a strong contender.

Pros

  • Lowest entry price for a new, complete turbo kit.
  • Preserves AC and power steering with no relocation.
  • Simple installation – good for first‑time turbo builders.
  • Precision has a solid reputation for reliability and customer support.

Cons

  • Journal‑bearing turbo lags slightly behind ball‑bearing kits (spool is still good, but not as sharp as AEM or Full‑Race).
  • Power ceiling is lower – not ideal if you plan to build the engine later and aim for 400+ hp.
  • No fuel system included; you must source injectors and pump separately.
  • Log manifold limits top‑end horsepower compared to tubular manifolds.

Visit Precision Turbo’s website →

How to Choose the Right RSX Turbo Kit for Your Build

All five kits can get you to the 300–400 hp target, but the best choice depends on your priorities. Consider the following factors before pulling the trigger:

1. Your Horsepower Goal – Now and Future

If you are certain you will never go beyond 350 whp, the Precision or Greddy kit is cost‑effective and proven. If you think you might build the bottom end later and aim for 500+ whp, go with the Full‑Race or AEM kit – their tubular manifolds and ball‑bearing turbos scale better. The Hondata K‑Pro route gives you the most flexibility to change parts incrementally.

2. Tuning Capability

Do you already have Hondata K‑Pro? If yes, you can save money by buying a kit without an ECU (Precision, or a custom bundle). If you plan to use a stock ECU with a piggyback, Greddy or AEM kits include (or offer) a basic tuner. But for serious power and reliability, K‑Pro is strongly recommended.

3. Installation Complexity & Mechanical Skill

Greddy and Precision kits are the easiest for DIY installation. AEM is slightly more involved because of the tubular manifold’s tight fit. Full‑Race requires the most skill – battery relocation and possibly subframe trimming. If you plan to pay a shop, factor $1,000–$2,000 for labour, which might push a budget kit like Precision into the same total cost as an AEM kit.

4. Supporting Mods & Safety

Do not forget to budget for a stronger clutch. The stock RSX clutch will slip at 300 whp. A Stage 2 or Stage 3 clutch (like ACT or Exedy) will cost around $400–$700. Also, consider upgrading the engine mounts – stiffer mounts reduce wheel hop and prevent the turbo piping from cracking. Finally, fuel system upgrades (injectors, pump, and a fuel pressure regulator) are non‑negotiable for 300+ hp.

5. Emissions & Inspections

If you live in a region with strict emissions testing, a CARB‑legal turbo kit may be required. Unfortunately, none of these kits are currently CARB‑approved for the RSX. You may need to maintain the stock catalytic converter and ensure no check engine lights. Some owners install a catalytic converter in the downpipe to pass visual inspection. Be sure to check local laws before buying.

Final Thoughts

The RSX platform continues to reward well‑planned turbo builds. Whether you choose the proven Greddy, the tuner‑centric Hondata K‑Pro approach, the responsive AEM, the premium Full‑Race, or the budget‑friendly Precision, each kit has a clear place in the market. The 300–400 hp range is a sweet spot – it transforms the RSX into a legitimate sports car without sacrificing reliability or requiring a built block. Pair any of these kits with proper tuning, a quality clutch, and good maintenance, and you will have a car that can hold its own on any back road or highway pull.

For more detailed build threads and real‑world dyno sheets, check out the RSX section on ClubRSX or Honda‑Tech. Use those resources to refine your parts list and learn from others who have already taken the plunge.