Introduction to the Precision 5858 Turbo Upgrade for the RSX Type-S

The Precision 5858 turbocharger is widely regarded as one of the most effective bolt-on upgrades for the RSX Type-S, capable of delivering impressive power gains while maintaining reasonable spool characteristics. Designed for engines producing up to 600 horsepower, this compact ball-bearing turbo offers an excellent balance between responsiveness and top-end flow. However, a successful installation requires more than simply bolting on parts—it demands meticulous preparation, proper hardware selection, and a thorough understanding of the K-series platform. This guide covers the essential best practices to ensure your Precision 5858 installation yields reliable, high-performance results.

Preparation Before Installation

Proper preparation significantly reduces installation time and prevents common mistakes. Before touching any bolts, take the following steps to set yourself up for success.

Review Factory Service Manuals and Turbo Documentation

Start by studying both the OEM Honda service manual for the RSX Type-S and the installation instructions provided with your Precision 5858 turbo. Understanding torque specifications, fastener locations, and routing diagrams prevents damage to critical engine components. If you no longer have the printed manual, AcuraWorld offers digital service manuals for the RSX platform.

Assess Your Engine’s Condition

A turbo system places additional stress on the engine. Perform a compression and leak-down test before installation to verify that your K20A2 or K20Z1 is healthy. Weak rings or worn valve seals will fail quickly under boost. Replace any suspect components—such as head gaskets, timing chain tensioners, or oil pumps—while the engine is accessible.

Gather All Necessary Parts and Fluids

Beyond the Precision 5858 kit, you will need:

  • High-quality synthetic engine oil (5W-30 or 10W-40) and OEM oil filter
  • Coolant (Honda Type 2 or equivalent)
  • New gaskets for the exhaust manifold, turbo flange, and downpipe
  • Stainless steel exhaust studs and locking nuts
  • Heat wrap or ceramic coating for the downpipe and hot side
  • Boost controller (manual or electronic) and boost gauge
  • Fuel system upgrades: larger injectors (at least 1000cc), a Walbro 450 or AEM 340 fuel pump, and a Flex Fuel sensor if using E85
  • Intercooler and piping (2.5" to 3" recommended)
  • Blow-off valve (dual-piston or high-flow recirculating style)

Having everything on hand before you begin saves repeated trips to the auto parts store.

Tools Required for Installation

Using the correct tools prevents stripped fasteners and damaged components. Below is a comprehensive list of what you will need:

  • Metric socket set – 10mm, 12mm, 14mm, 17mm, 19mm deep and shallow
  • Torque wrench – ⅜" and ½" drives, range 10-150 ft-lbs
  • Combination wrenches – 10mm to 19mm with flex-head for tight spaces
  • Screwdrivers – Phillips #2 and flathead (standard and long reach)
  • Intercooler pipe pliers – for spring clamps and T-bolt clamps
  • Oil and coolant catch containers – at least 2 gallons each
  • Pry bar and rubber mallet – for stubborn exhaust parts
  • Brake cleaner and shop rags – for cleaning mating surfaces
  • Digital caliper or feeler gauges – to verify turbo flange thickness
  • Thread chaser or tap set – for cleaning threads in the oil pan and block

Step-by-Step Installation Process

Follow these expanded instructions for a trouble-free installation. Work methodically and never force components into place.

1. Remove the Stock Turbo and Manifold

Disconnect the battery negative terminal and drain the engine oil and coolant into approved containers. Remove the intake box, air filter, and all intake piping. Unbolt the factory exhaust manifold heat shield.

To access the turbo flange, you will need to:

  • Disconnect the exhaust from the manifold.
  • Unplug the oxygen sensors (front and rear) and move the harness aside.
  • Remove the catalytic converter or test pipe.
  • Unbolt the stock exhaust manifold from the cylinder head (17mm bolts, often torqued to 33 ft-lbs).

Important: Soak all exhaust fasteners in penetrating oil the night before to reduce the risk of snapping studs. If a stud breaks, drill and extract it with care to avoid damaging the head threads.

Once the manifold is free, lift the stock turbo assembly out through the top of the engine bay. Remove the oil drain line and turbo oil feed line.

2. Prepare the Precision 5858 Turbo

Inspect your new turbo for any shipping damage. Ensure the compressor wheel spins freely and that the shaft has minimal axial play. Apply a few drops of engine oil to the thrust bearing and spin the wheel by hand to distribute lubrication. Verify that all fittings—oil inlet, oil drain, and coolant lines—are correctly sized and that gaskets are included. If your kit lacks a turbo blanket, consider purchasing one to reduce under-hood temperatures.

If you plan to rotate the compressor housing for a different outlet orientation, follow Precision Turbo’s guidelines exactly. Over-tightening the housing bolts can warp the cover.

3. Install the Precision 5858 Turbo

Position the new turbo onto the exhaust manifold (or a high-quality aftermarket manifold designed for the Precision 5858 flange). Use new copper gaskets at the manifold-to-turbo joint. Install the manifold studs with thread locker (medium strength) and torque them to 25-30 ft-lbs. Torque the turbo-to-manifold fasteners to the manufacturer’s specification—typically 35-40 ft-lbs.

Reconnect the oil supply line (usually from the block or a sandwich plate) and the oil drain line. Ensure the drain line slopes downward without kinks to prevent oil backup. Connect coolant lines per your kit’s routing; if your car originally had a water-cooled turbo, use the stock lines or upgrade to AN fittings.

Attach the downpipe and all exhaust piping. Use exhaust hangers that support the weight without binding. Secure the downpipe with lock nuts and reinstall the oxygen sensors.

4. Install the Intercooler and Piping

Mount the intercooler in front of the radiator or in the lower bumper opening. Use silicone couplers and T-bolt clamps on all joints. Route the charge pipes to the throttle body and turbo compressor outlet. Ensure the blow-off valve is positioned after the intercooler (post-MAF if you are keeping a mass air flow sensor) to avoid stalling issues.

Check for clearance with the radiator fan and A/C lines. Trim any plastic shrouds if necessary. Pressure test the entire intake system to 20 psi with a boost leak tester – leaks as small as 1 psi will reduce performance.

5. Check All Connections and Double-Clearance

Visually verify that every bolt, clamp, and hose is tight. Use a torque wrench for critical fasteners. Inspect the area around the turbo for any loose wiring that might contact hot surfaces. Add heat shielding or DEI boot covers over spark plug wires and the main harness near the downpipe.

Fill the engine with fresh oil (5 quarts, then check dipstick). Refill coolant, ensuring you bleed air from the system. Crank the engine with the fuel pump fuse removed to prime the oil system – watch the oil pressure gauge; you should see pressure within 5-10 seconds. Reinstall the fuse and start the engine.

6. Reconnect the Battery and Perform Initial Startup

Once the engine idles, let it warm up to operating temperature. Monitor oil pressure (target 20-30 psi at idle, 50+ psi under load), coolant temperature, and fuel trims. Listen for unusual noises – a high-pitched whistle could indicate an intake leak; a rattling sound might mean a loose heat shield. Shut the engine off if you see smoke or oil leaks.

During the first run, do not rev the engine beyond 3000 RPM. Allow the turbo bearings to break in for 5-10 minutes of light driving before any boost attempts.

Post-Installation Tuning and Calibration

Installing the Precision 5858 changes the air-fuel ratio and ignition timing requirements dramatically. You must tune the ECU to match the new hardware. Do not drive the car under boost without a proper tune – severe engine damage will occur.

  • Base map: Use a reliable base map from a reputable tuner like K-Tuned or Hondata. If you are using an aftermarket ECU such as a MoTeC or Haltech, start with conservative timing (5-10° at high load).
  • Fuel adjustments: Install a wideband O2 sensor and adjust fuel tables to target 11.5:1 air-fuel ratio under boost (12.0:1 for E85).
  • Ignition timing: Retard timing in boost onset to prevent detonation. A good starting point is 15° at 0 psi linearly dropping to 8° at 20 psi.
  • Boost control: Set initial wastegate pressure (typically 5-7 psi). Only increase boost after confirming the fuel system can deliver adequate pressure.

Consider Hondata’s S300 tuning resources for detailed step-by-step calibration guidance.

Essential Post-Installation Tips

Maintaining your Precision 5858 turbo and supporting systems ensures longevity and consistent performance.

  • Oil changes: Switch to a high-quality synthetic oil with a robust additive package. Change oil and filter every 3,000 miles. Consider adding a magnetic oil drain plug to catch wear metals.
  • Cool-down period: After any hard run, allow the engine to idle for 30-60 seconds before shut down to prevent oil coking in the turbo bearings.
  • Fuel quality: Use 93 octane pump gas at a minimum. For higher boost levels (18+ psi), blend with E85 or use race gas. Regularly test fuel for ethanol content if using flex fuel.
  • Monitor boost: Install a quality boost gauge and log peak boost. Never exceed the turbo’s rated maximum (60 psi for the 5858, but stay under 30 psi for street use).
  • Check for leaks: Once per month, inspect all hose clamps, intercooler couplers, and exhaust gaskets. Tighten any that feel loose.

Common Pitfalls and How to Avoid Them

Many RSX owners encounter issues during or after installation. Knowing these pitfalls saves time and money.

  • Insufficient oil return: The oil drain line must be at least -10 AN and slope steadily downward into the oil pan. A kinked or too-small drain causes oil to leak past the turbo seals, resulting in blue smoke. If necessary, relocate the oil pan bung.
  • Heat soak: The Precision 5858 sits close to the radiator and valve cover. Wrap the downpipe and turbine housing in titanium or fiberglass wrap. Install a turbo blanket. Consider a vented hood to extract hot air.
  • Clutch slip: Stock clutches cannot handle 350+ whp. Upgrade to a stage 3 or multi-plate clutch from ACT, Exedy, or Competition Clutch before tuning.
  • Fuel system starvation: The stock fuel pump and injectors max out near 250 whp. Always install a high-flow pump and injectors before the first startup.

For additional community-driven advice, check the Club RSX discussion thread on Precision 5858 builds.

Conclusion

Installing a Precision 5858 turbo on your RSX Type-S is a rewarding project that transforms the driving experience. By following the best practices outlined here—thorough preparation, correct tooling, careful installation, and professional tuning—you can expect a reliable, high-horsepower setup that performs for years. Always prioritize oil system integrity, heat management, and fuel delivery. Whether you are aiming for a stout 400 hp daily driver or a 600 hp track monster, the Precision 5858, when installed correctly, delivers exceptional results. Remember to continue learning and refining your setup; the K-series community is rich with experience. Visit Precision Turbo’s official website for additional technical resources and compatibility charts.