The Honda B-series engine has earned a legendary reputation among enthusiasts for its high-revving nature, robust construction, and remarkable tuning potential. Whether you are building a daily-driven Civic or a track-focused Integra, the camshaft upgrade is one of the most effective modifications for reshaping the engine’s power delivery. A properly selected camshaft can transform a peaky stock powerband into a strong, broad curve from 1500 rpm all the way to 7000 rpm and beyond. This article provides a comprehensive guide to B-series camshaft upgrades, covering the technical fundamentals, selection criteria, supporting modifications, installation steps, and tuning requirements. By the end, you will have the knowledge to choose the right cam for your goals and extract maximum performance from your B-series engine.

Understanding the B-Series Engine Family

The B-series engine family, produced by Honda from the late 1980s through the early 2000s, spans multiple displacements and configurations. The most common variants are the B16A, B18C, and B20B. Each has distinct characteristics that influence camshaft selection.

  • B16A – 1.6-liter, high-revving design found in the Civic Si, CRX Si, and Del Sol. Stock output typically 160 hp in USDM versions, but JDM variants (B16B) produce 185 hp. The B16A loves RPM and responds well to cams that shift the powerband upward.
  • B18C – 1.8-liter, found in the Acura Integra GS-R and Type R. The B18C1 (GS-R) produces around 170 hp, while the B18C5 (Type R) makes 195 hp. The larger displacement provides more torque low in the rev range, and cam upgrades can further enhance both mid-range and top-end.
  • B20B/Z – 2.0-liter, typically from the Honda CR-V. This engine has low compression and small ports, but its displacement is ideal for torque builds. With B20VTEC conversions (using a B16 or B18 head), camshaft upgrades become especially potent.

Understanding these differences is critical because a camshaft that works beautifully on a B16A may be too aggressive or cause piston-to-valve clearance issues on a B20. Always verify compatibility with your specific block and head combination.

Camshaft Fundamentals: How They Shape Power

A camshaft influences engine performance through three primary parameters: lift, duration, and lobe separation angle (LSA). The interaction of these variables determines where in the RPM range the engine produces peak torque and horsepower.

Lift refers to how far the camshaft opens the valve. Higher lift allows more air and fuel into the cylinder, but requires stiffer valve springs to prevent float at high RPM. Duration is the number of crankshaft degrees that the valve remains open. Longer duration shifts the powerband higher, often at the expense of low-rpm torque. Lobe Separation Angle (LSA) affects overlap—the period when both intake and exhaust valves are open. A wider LSA (110-114 degrees) reduces overlap, improving low-end torque and idle quality. A tighter LSA (104-108 degrees) increases overlap, favoring high-RPM horsepower but making the idle rough and reducing manifold vacuum.

For a B-series engine aiming to produce strong power from 1500 to 7000 rpm, a cam with moderate duration (260-268 degrees intake, 264-272 degrees exhaust) and lift around 11.5-12.5 mm, paired with an LSA of 110-112 degrees, is often ideal. This profile retains good driveability while adding significant mid-range and top-end punch.

Benefits of a Camshaft Upgrade

Swapping a stock cam for a performance grind yields measurable gains across the rev range. Key benefits include:

  • Increased area under the curve – Not just peak power, but more power throughout the usable RPM band.
  • Higher peak horsepower and torque – Typical gains of 15-30 whp depending on cam aggressiveness and supporting mods.
  • Improved throttle response – A faster rising torque curve makes the engine feel livelier.
  • Extended powerband – Many performance cams sustain power well past 7000 rpm, allowing you to shift later and stay in the sweet spot.

These benefits are most noticeable when the camshaft is matched with a proper intake, header, exhaust, and engine management. Stock components often become bottlenecks, limiting the gains from a cam upgrade alone.

Choosing the Right Camshaft for Your Build

Selecting a camshaft requires evaluating your engine’s intended use, existing modifications, and realistic power goals. Here are the critical factors:

Intended Use

For a daily driver that sees occasional spirited driving, a mild street cam (e.g., Skunk2 Tuner Stage 1 or Brian Crower Stage 2) provides a noticeable gain without ruining idle quality or low-end torque. For a dedicated track car or drag racer, more aggressive profiles (Skunk2 Stage 3 or higher) are appropriate, but they will sacrifice low-rpm performance and may require upgraded valvetrain components.

Head and Compression Ratio

Your cylinder head’s port flow capacity determines how much lift and duration you can effectively use. A stock B16 head with small ports will stall with a massive cam. Porting the head or swapping to a PR3 or B16B casting allows larger cams to deliver their full potential. Compression ratio also matters: higher static compression (11:1 or more) helps retain low-end torque even with longer duration cams.

Valve Train Compatibility

Aggressive cam profiles with high lift and fast ramps require upgraded valve springs, retainers, and often new valves. Stock springs will experience valve float above 7500 rpm with a mild performance cam, and much sooner with a race grind. Always upgrade the springs and retainers when installing a cam with more than 11.5 mm lift or a duration above 270 degrees. Additionally, aftermarket cam gears allow fine-tuning of the cam timing to shift the powerband up or down.

Brand Reputation and Cam Specs

Reputable manufacturers for B-series camshafts include Skunk2 Racing, Brian Crower (BC), Toda Racing, CAT Cams, and Crower. Each offers multiple stages. Compare the actual specifications (lift, duration at 0.050 inch, LSA) rather than relying solely on marketing claims. A forum search for dyno results of a particular cam on a similar setup is invaluable.

Types of B-Series Camshaft Upgrades

Camshafts for the B-series range from mild bolt-ons to full race grinds. Here is a breakdown of common categories:

Stock Replacement / OEM+ Cams

These are copies of the B16A or B18C5 cams with slightly optimized profiles. Gains are modest (5-10 hp) but they require no supporting mods. Suitable for a beginner who wants a small improvement.

Stage 1 Performance Cams

Examples: Skunk2 Tuner Stage 1 (11.5 mm lift, 264 degrees duration). These offer a broad power increase with a slight idle lope and require only upgraded springs. Good for daily drivers with basic bolt-ons.

Stage 2 Performance Cams

Examples: BC Stage 2 (12.0 mm lift, 268 degrees duration). These shift the powerband higher but still retain decent low-end. Upgraded springs, retainers, and cam gears are recommended.

Stage 3 and Race Cams

Examples: Skunk2 Stage 3 (12.5 mm lift, 274 degrees duration) or Toda Spec C (12.9 mm lift, 284 degrees duration). These require a fully built head, high compression, aggressive tuning, and are intended for competition use. Idle is rough, and low-rpm torque below 2000 rpm is minimal or nonexistent.

Custom Grinds

For unique builds (turbo, high-compression, specific RPM targets), custom ground cams from specialists like Web Cams or Colt Cams can be ordered. These allow you to specify lift, duration, and LSA to exactly match your setup.

Supporting Modifications You Shouldn’t Skip

A camshaft upgrade alone will not deliver its full potential without complementary parts. Plan to address the following:

  • Valve Springs and Retainers – Necessary to prevent valve float. Dual springs are recommended for aggressive cams.
  • Cam Gears – Adjustable cam gears allow you to dial in the intake and exhaust timing independently, optimizing the powerband for your specific setup.
  • ECU Tuning – A piggyback or standalone ECU (such as Hondata S300, AEM EMS, or K-Pro with an adapter) is mandatory to adjust fuel and ignition maps. Without tuning, the engine will run poorly and may suffer detonation.
  • Intake and Exhaust Upgrades – A cold air intake, larger throttle body (62-65 mm), and performance header (e.g., Kamikaze, RMF, Hytech) eliminate restrictions.
  • Fuel System – Larger fuel injectors (440-550 cc for naturally aspirated builds) and a higher-flow fuel pump may be needed with aggressive cams or high RPM operation.

Neglecting any of these will leave power on the table and risk engine damage.

Installation Overview: Step-by-Step Guidance

Installing a camshaft is a moderate mechanical task that requires precision. While we cannot cover every torque specification here, the following sequence outlines the process:

  1. Preparation – Gather tools: torque wrench, feeler gauges, cam gear wrench, piston stop, dial indicator (for degreeing). Remove the battery, intake, radiator fan shroud, and cam cover.
  2. Timing belt removal – Set the engine to Top Dead Center (TDC) on cylinder 1. Remove the serpentine belt, tensioner, and timing belt. Secure the crankshaft from rotating.
  3. Camshaft removal – Remove the rocker arms (or VTEC rocker assemblies on DOHC VTEC engines). Unbolt the cam cap journals in a spiral pattern. Lift out the old camshaft and clean the bearing surfaces.
  4. New camshaft installation – Lubricate the cam lobes and journals with assembly lube. Install the new cam, ensure the cam gear key aligns, and torque the cap bolts in stages to spec (typically 7-9 ft-lbs for the small bolts, 15-17 ft-lbs for the main cap bolts).
  5. Degreeing the cam – Use a degree wheel and dial indicator to verify that the cam timing matches the manufacturer’s specifications. If not, install an adjustable cam gear and set the intake centerline.
  6. Reinstall timing belt – Follow the manufacturer’s timing belt tension procedure. Rotate the engine by hand twice to confirm no interference.
  7. Valve clearance adjustment – B-series engines use mechanical adjusters. Check and set the clearances per the camshaft’s recommended specs (often 0.006-0.008 inch intake, 0.007-0.009 inch exhaust on performance cams).
  8. Final assembly – Reinstall the cam cover, throttle body, intake, and all accessories. Refill coolant if drained.

Important: After installing a performance cam, you must check piston-to-valve clearance, especially on B20V builds where the piston pockets are smaller. Use clay on the piston dome and rotate the engine; measure the minimum clearance. If less than 0.080 inch, you may need deeper valve reliefs or a different cam.

Tuning After the Cam Upgrade

Once the camshaft is installed and the engine is running, proper tuning is essential. A basemap from the cam manufacturer can get you started, but a professional dyno tune is strongly recommended. Key tuning adjustments include:

  • Fuel mapping – Wider lobe centers and increased overlap change volumetric efficiency. Expect to add fuel in the mid to high RPM ranges and sometimes reduce it in the low-range.
  • Ignition timing – Aggressive cams often require slightly less timing at high RPM to avoid detonation, but more timing near the torque peak.
  • VTEC engagement point – With a bigger cam, the VTEC crossover may need to be raised or lowered. Typically, performance cams work well with VTEC engaging between 4000 and 4600 rpm.

An aftermarket ECU with datalogging capability (e.g., Hondata S300) allows you to adjust VE tables and see real-time corrections. Tuning yields not only power but also reliability; a poorly tuned cam car can knock and melt pistons.

Potential Challenges and How to Address Them

Upgrading the camshaft is not without trade-offs. Here are common issues and solutions:

  • Rough idle – Aggressive cams with high overlap cause a choppy idle. This is normal; you can raise the idle speed to 900-1100 rpm to stabilize it.
  • Loss of low-end torque – Especially with stage 3 or race cams. Consider increasing compression ratio, using a more aggressive intake manifold, or lowering the VTEC point.
  • Valve float – If you reused stock springs, upgrade to dual springs immediately. Valve float can bend valves and destroy the engine.
  • Increased valvetrain noise – More lift and faster ramps naturally create more noise. Use high-quality engine oil (5W-40 or 10W-40 synthetic) with adequate zinc.
  • Clearance issues – Always check piston-to-valve and valve-to-valve clearance. If clearance is insufficient, flycut the pistons or select a milder cam profile.

Being aware of these challenges lets you plan ahead and avoid frustration.

Real-World Dyno Results: What to Expect

To illustrate, consider a typical B18C1 (GS-R) with bolt-ons: cold air intake, header, 2.5-inch exhaust, and a mild tune. Adding a Skunk2 Stage 2 cam (12.0 mm lift, 268/272 duration) and adjustable cam gears, with upgraded springs and retainers, typically yields the following gains:

  • Peak horsepower increases from 170 whp to 195-200 whp
  • Peak torque rises from 115 wtq to 130 wtq
  • Power from 1500-3000 rpm is slightly reduced (by 3-5 hp) but still strong
  • Power from 4000-7000 rpm gains 15-25 hp throughout
  • Engine now pulls to 7800 rpm versus stock’s 7200 rpm

For a B16A with aggressive cams (Skunk2 Stage 3), a built head, and high compression (11.5:1), expect 220+ whp at 8500 rpm, with usable power from 4500 rpm upward. The low-end below 2500 rpm is significantly weaker, but the car becomes a beast on the track. Always review dyno graphs from similar builds to set realistic expectations.

Conclusion

Upgrading the camshaft in your B-series engine is one of the most rewarding modifications when done correctly. By understanding the interplay of lift, duration, and LSA, choosing a cam that matches your engine and driving style, and investing in supporting hardware and professional tuning, you can unlock impressive gains from 1500 to 7000 rpm and beyond. The B-series platform is incredibly responsive to cam upgrades, and with careful planning, your build will deliver the performance you have been chasing.

For further reading, consult the technical specifications from Skunk2 Racing, see detailed installation guides on Honda-Tech, or explore tuning resources from Hondata. Take your time, plan every step, and enjoy the process of turning your B-series into a high-revving powerhouse.