For owners of the Acura RSX Type S—powered by the legendary K20Z1 engine—the quest for more power is a never-ending pursuit. While bolt-on modifications like intake and exhaust systems offer incremental gains, the camshaft remains one of the most impactful mechanical changes you can make to your engine’s breathing. Aftermarket camshafts promise a substantial increase in horsepower and a more aggressive powerband, but the investment is not trivial. This expanded guide will take a deep dive into the real-world performance gains of 15–20 horsepower from a typical $700 camshaft set, the supporting modifications required, installation costs, and whether this upgrade truly delivers value for your RSX Type S.

What Are Camshafts and Why Do They Matter?

Before evaluating the worth of aftermarket camshafts, it’s essential to understand their function. The camshaft is a rotating shaft with precisely ground lobes that open and close the engine’s intake and exhaust valves. The shape, duration, and lift of these lobes determine how much air and fuel enter the combustion chamber and how efficiently exhaust gases exit. Factory camshafts are engineered as a compromise between power, fuel economy, emissions, and idle quality. Aftermarket camshafts, by contrast, prioritize peak horsepower at higher RPM, often sacrificing low-end torque and idle smoothness for top-end punch.

On the RSX Type S, the stock K20Z1 camshafts are already more aggressive than those found in base RSX or Civic Si engines, but there is still room for improvement. Performance camshafts increase valve lift and duration, allowing the engine to inhale more air at high RPM. This directly translates to higher horsepower figures when the engine is properly tuned and supported by complementary modifications.

Real-World Performance Gains: Beyond the 15–20 HP Claim

Enthusiast forums and dyno result archives consistently report that a set of aftermarket camshafts—such as those from Skunk2, Brian Crower, or Rocket Motorsports—can yield between 15 and 20 wheel horsepower on a K20Z1 with minimal supporting mods. However, these numbers do not tell the full story. The shape of the horsepower and torque curve changes dramatically. Where a stock RSX Type S makes peak power around 7,800 RPM and runs out of breath near the 8,100 RPM redline, a camshaft upgrade can extend the powerband an additional 500–800 RPM. This allows the engine to continue pulling hard past the factory cut, often requiring a tune that raises the rev limit to 8,300–8,500 RPM to exploit the new cams.

Dyno Evidence and Curve Characteristics

To validate the 15–20 HP claim, we can look at published dyno results from reputable tuning shops. A common setup—Stage 2 camshafts (around .480” lift / 264° duration) with a K20Z1 intake manifold, cold-air intake, and a quality header—produces approximately 215–220 wheel horsepower. The stock K20Z1 in similar configuration typically makes 198–203 whp. That is a real gain of 12–17 whp. More aggressive Stage 3 cams (around .500” lift / 272° duration) can push gains to 20–25 whp, but at the cost of a lumpy idle and a significant dip in low-RPM torque below 3,500 RPM.

The 15–20 HP advertised is therefore a realistic ballpark for a moderately aggressive street cam with a proper tune.

Important note: These gains are not free. To realize the full potential, you must pair the cams with a professional tune—either via a Hondata K-Pro or K-Tuned ECU. Without tuning, the engine management system will not adjust fuel and ignition timing to match the new cam timing, and you may actually lose power in some areas while risking detonation.

Factors That Influence Realized Gains

Simply bolting in camshafts does not guarantee 15–20 HP. Several variables determine whether you hit that number, exceed it, or fall short.

Engine Configuration and Supporting Modifications

  • Intake System: A high-flow cold-air intake or short-ram intake helps supply the additional air the camshafts demand. Stock airboxes may become restrictive.
  • Exhaust System: A 2.5-inch or 3-inch cat-back exhaust, coupled with a high-flow catalytic converter (or a test pipe) and a quality header, reduces backpressure that could choke the engine at high RPM.
  • Valvetrain Upgrades: Aggressive camshafts with higher lift require stiffer valve springs and retainers to prevent valve float at elevated RPM. This is not optional for Stage 2 and above—skipping this can lead to catastrophic engine damage. Budget an extra $200–350 for springs/retainers.
  • Fuel System: At higher RPM and power levels, stock fuel injectors may be near their limit. A larger fuel pump (e.g., Walbro 255 lph) is a low-cost insurance upgrade.

Tuning: The Non-Negotiable Variable

No other factor matters more than a proper calibration. The RSX Type S uses an electronic throttle body and a complex ECU (either the stock K20Z1 ECU or a Hondata K-Pro). Aftermarket camshafts alter airflow characteristics, requiring adjustments to fuel maps, ignition timing, and VTEC engagement points. A skilled tuner will dial in cam timing using adjustable cam gears (often included in higher-end cam kits) to shift the powerband to match your driving style. Expect to pay $400–$600 for a dyno tune or $200–$400 for an e-tune.

This brings the total investment well beyond the $700 camshaft cost.

Camshaft Profile Selection

  • Street / Mild: Duration 252°–260°, lift 0.440”–0.480”. Retains decent low-RPM torque, minimal idle change. Gains of 12–18 HP.
  • Street Performance / Stage 2: Duration 264°–272°, lift 0.480”–0.510”. Noticeable lope at idle, powerband shifts higher. Gains of 18–25 HP.
  • Race / Stage 3: Duration 274°–280°, lift 0.520”+. Rough idle, poor low-RPM driveability, requires high stall converter for autos. Gains can exceed 25 HP but come with significant trade-offs.

For most street-driven RSX Type S, a Stage 2 camshaft provides the best balance of drivability and power. The original article’s 15–20 HP figure aligns well with a Stage 2 setup when properly tuned.

Cost Breakdown: The True Investment

The $700 figure quoted in the original article is achievable for entry-level camshafts (e.g., Skunk2 Stage 1 or Pro Series) but many performance-oriented owners spend more. Let’s break down a realistic budget for a complete camshaft installation on an RSX Type S.

Parts List and Estimated Costs

  • Aftermarket camshafts (Stage 2, brand such as Brian Crower or Skunk2): $600–$800
  • Valve springs and retainers: $200–$350
  • Adjustable cam gears (optional but recommended): $150–$250
  • Head gasket and head bolt set (if removing cylinder head): $100–$200 (only needed if engine is apart)
  • Timing chain tensioner and gaskets: $50–$100
  • Coolant and oil: $30–$60
  • Total parts cost: $1,130–$1,760

Labor Costs

Installing camshafts is not a beginner-level job. It requires removing the valve cover, timing chain, cam gears, and often the cylinder head to access the camshafts properly. A professional shop will charge 6–10 hours of labor at $100–$150 per hour. That adds $600–$1,500. If you are mechanically skilled and have the tools, DIY labor is free but expect a full weekend of work.

Tuning Costs

  • Hondata K-Pro ECU (if you don’t already have one): $595–$895
  • Professional dyno tune: $450–$600
  • Total tuning investment (without ECU): $450–$600

Adding everything: a bare-bones camshaft install using stock valvetrain and no tune might cost $700 for parts + $0 labor = $700, but this is ill-advised. A realistic, safe, and effective build runs $2,000–$3,500 when you include required complementary parts, labor, and tuning. The original article’s $700 investment is misleadingly low if you want reliable, optimized results.

Pros and Cons Revisited

Advantages of Aftermarket Camshafts

  • High-RPM Power Extension: Gains of 15–25 HP above 6,000 RPM transform the car’s top-end pull, especially on track or during aggressive highway passing.
  • Improved Throttle Response (with tune): A well-tuned camshaft setup can sharpen response in the VTEC engagement zone (typically 5,500–6,500 RPM on aftermarket cams).
  • Customizable Powerband: By selecting the right cam profile and pairing with adjustable cam gears, you can shift torque higher or lower to suit your driving.
  • Exhaust Note: A more aggressive cam creates a distinct, rhythmic lope at idle that many enthusiasts find appealing.

Disadvantages and Risks

  • Loss of Low-End Torque: With longer duration, the engine’s low-RPM efficiency drops. Daily driving below 4,000 RPM may feel lazier if the cams are too aggressive.
  • Increased Wear and Maintenance: Higher valve lift and stiffer springs accelerate valvetrain wear. Valve lash adjustments may be needed every 15,000–20,000 miles, and cam journals may wear if oiling is inadequate.
  • Idle Quality Degradation: Stage 2 and Stage 3 cams cause a rough, hunting idle that may not be suitable for a daily driver in stop-and-go traffic.
  • Hidden Costs: As detailed above, the true cost is often 2x to 3x the advertised camshaft price when you include supporting parts, labor, and tuning.
  • Emissions Compliance: Aggressive cams can shift the powerband past the effective range of the catalytic converter, potentially causing failure of emissions tests. Some tuners disable the secondary O2 sensor, which may be illegal in certain jurisdictions.

Comparing Aftermarket Camshafts to Other Modifications

Before committing to a camshaft swap, it is wise to consider the cost-per-horsepower ratio of other upgrades.

ModificationEstimated HP GainCost (Parts + Tune)Cost per HP
Cold-air intake + tune8–12 HP$500–$800$50–$100/HP
Header + exhaust + tune12–18 HP$1,000–$1,500$55–$125/HP
Stage 2 camshafts (with supporting mods + tune)15–20 HP$1,500–$3,000$75–$200/HP
Nitrous oxide (50 HP shot)40–55 HP$600–$1,000$12–$25/HP
Supercharger kit60–100 HP$3,500–$5,500$35–$90/HP

As the table shows, camshafts offer competitive cost-per-horsepower compared to bolt-on combinations but are less cost-effective than forced induction. However, camshafts preserve the engine’s naturally aspirated character and reliability while providing a more linear power delivery compared to a power adder. For RSX Type S owners who want to maintain the K20’s high-revving thrill without the complexity of a turbo or supercharger, camshafts remain a classic choice.

Installation Considerations

Installing camshafts on a K20 engine is not a weekend project for the faint of heart. The camshafts are driven by a timing chain, which requires precise timing alignment. Mistakes can lead to bent valves or piston-to-valve contact. Most experienced DIYers will budget a full two days for the work, including removal of the cylinder head (to access the camshafts without removing the timing chain entirely). If you are not comfortable with engine internal work, professional installation is strongly recommended.

Can You Install Without Removing the Head?

It is possible to swap camshafts with the cylinder head in place by holding the timing chain tensioner and carefully rotating the cams out. However, this is risky because the timing chain can skip teeth, and it is difficult to verify proper timing without removing the head and cam caps. Many tuners recommend removing the head, especially if you are also upgrading springs and retainers. The extra labor is worthwhile for peace of mind.

External Resources for Further Research

To make an informed decision, we encourage you to read real-world experiences from RSX Type S owners and professional builders.

Note: Some links above are illustrative examples. We recommend searching specific brand forums and trusted tuning shops for the most current data.

Final Verdict: Is the $700 Investment Worth It?

If you are expecting to spend exactly $700 and gain 15–20 reliable horsepower on your RSX Type S, the reality is more complex. The camshafts themselves can be purchased for around $700, but a safe and effective installation pushes the total investment to $2,000–$3,500. However, for enthusiasts who value a high-RPM, naturally aspirated powerband and are willing to tune the car properly, the result is a noticeably faster, more exciting vehicle. The 15–20 HP gain is very real when measured on a dyno with proper tuning and supporting mods, and the sound of a VTEC engine with aggressive cams hitting its stride is something no bolt-on can replicate.

Aftermarket camshafts are worth the investment if: you have already addressed intake and exhaust restrictions, are prepared for the cost of tuning and valvetrain upgrades, and prioritize top-end power over low-RPM drivability. If you are looking for a simple bolt-on experience, start with a cold-air intake and a K-Tuner base map—camshafts are the next step for dedicated performance seekers.

Ultimately, the decision comes down to your performance goals and budget. For the RSX Type S enthusiast who wants to extract the maximum naturally aspirated potential from the K20Z1, camshafts remain one of the most rewarding modifications available.