Introduction

The Pure Turbos Stage 2 M3 Turbo Kit is a proven upgrade for owners of the BMW M3 (E9X S55 or equivalent platform) seeking substantial power gains without sacrificing daily drivability. This kit replaces the factory turbochargers with larger, high-flow units that can support up to 650+ wheel horsepower when paired with proper supporting mods and tuning. While the installation is a significant mechanical undertaking, it can be completed at home with preparation, patience, and the right tools. This guide provides a thorough, step-by-step walkthrough to help you perform the swap correctly the first time.

Before beginning, understand that this project involves heavy components, high-pressure oil and coolant lines, and critical torque specifications. If you are not comfortable with mid-to-advanced engine work, consider enlisting a professional shop. However, for the dedicated enthusiast, installing the Pure Turbos Stage 2 kit is a rewarding experience that transforms your M3 into a serious performer.

Preparation and Tools

Proper preparation eliminates most installation headaches. Set aside a full weekend and ensure you have a clean, well-lit workspace. The following list covers the essentials:

  • Pure Turbos Stage 2 Turbo Kit – Ensure all components (turbos, gaskets, hardware, oil/water lines) are present. Check the kit against the packing list included by Pure Turbos.
  • Socket and wrench set – Metric, 8mm to 21mm, including deep sockets and swivels for tight spaces.
  • Torque wrench – Two are ideal: a 3/8” drive for small bolts (5–80 ft-lb) and a 1/2” drive for larger fasteners (up to 150 ft-lb).
  • Jack and jack stands – Rated for the M3’s weight (approximately 3,600 lbs).
  • Coolant and oil – Use BMW-approved coolant (blue) and 5W-30 or 0W-40 synthetic oil. Prepare an extra quart for priming.
  • Shop towels, degreaser, and brake cleaner – For cleaning mating surfaces.
  • Feeler gauge – Not typically needed for this kit, but useful for verifying wastegate clearance.
  • Digital camera or phone – Take photos of every disassembly step to aid reassembly.
  • PB Blaster or similar penetrating oil – Loosen stubborn exhaust manifold nuts.
  • Disposable gloves and safety glasses – Protect yourself from oil, coolant, and debris.

Also verify you have the latest software from a reputable BMW tuner (e.g., ECUtek or Bootmod3) loaded onto your ECU, as the Stage 2 turbos require a custom tune to avoid overboost and fuel cut. Contact your tuner before starting to confirm they support the Pure Stage 2 hardware.

Safety Precautions

Working on a modern turbocharged engine involves hot surfaces, pressurized fluids, and heavy parts. Follow these safety rules:

  • Disconnect the battery (negative terminal) and wait at least 30 minutes for the DME capacitors to discharge. This prevents accidental short circuits and airbag deployment.
  • Work on a cold engine. Even after sitting overnight, exhaust manifolds can stay warm. Allow the car to cool for several hours before starting.
  • Use jack stands – Never rely on a jack alone. Place stands under the frame rails or designated lift points.
  • Wear eye protection when using compressed air or brake cleaner.
  • Have a fire extinguisher rated for Class B (flammable liquids) and Class C (electrical) nearby.

Step-by-Step Installation

Step 1: Removing the Stock Turbochargers

This is the most time-consuming portion. Allow 3–5 hours if you are methodical. The exact procedure varies by year (S55 vs N54-based M3, but this guide focuses on the S55 found in the F80/F82 M3/M4). Always refer to your vehicle’s service manual for variant-specific torque specs.

1A: Access and Drain Fluids

  • Remove the engine cover (six 8mm bolts).
  • Drain the engine oil (warm oil drains faster) into a clean container. Remove the oil filter to speed up draining.
  • Drain the coolant from the radiator petcock and the block drain plug (driver’s side, near the oil filter housing). Collect old coolant for proper disposal.

1B: Disconnect Intake and Charge Air Pipes

  • Remove the intake air filter housings and mass airflow sensors.
  • Unbolt the charge air cooler (CAC) – typically two lower brackets and two upper bolts. Carefully lower the CAC; it is heavy and filled with residual coolant. Disconnect the intercooler coolant pump electrical connector.
  • Disconnect all charge pipes between the turbos and the CAC. Label each hose clamp for orientation during reinstallation.

1C: Unbolt Exhaust and Manifold

  • Loosen the exhaust downpipes from the turbo outlets. Use penetrating oil on the nuts if they are rusty. The V-bands often require a 13mm wrench.
  • Support the catalytic converters (or catless downpipes) with a jack stand to avoid straining the exhaust hangers.
  • Remove the intake manifold brace (if equipped).
  • Working from underneath, unbolt the exhaust manifolds from the cylinder head. There are ten M10 bolts per side. Follow a star pattern to prevent warping.
  • With the manifolds free, carefully maneuver the assembly (manifold plus stock turbo) out from between the engine and frame rail. It may be necessary to rotate the turbo to clear the subframe.

1D: Oil and Coolant Lines

  • Disconnect the oil feed line from the top of each turbo (usually a 17mm banjo bolt). Have rags ready for any residual oil.
  • Disconnect the coolant hoses from the turbo water jackets. Use pliers to loosen spring clamps. Expect some coolant spillage.
  • Remove the oil return line from the bottom of the turbo (two 10mm bolts). The gasket should be replaced.

Once both turbos are free, set them aside. Inspect the cylinder head mounting surface and clean any gasket residue with a plastic scraper. Do not use metal scrapers on the aluminum head.

Step 2: Preparing the Pure Turbos Stage 2 Kit

Before installation, bench-test the wastegate actuators. Using a hand vacuum pump, apply vacuum to each actuator and verify that the rod moves freely and holds vacuum. The Stage 2 turbos often feature upgraded actuators with dual diaphragms. Adjust the actuator rod length to the same preload as the stock unit (typically 0.5–1mm of preload). Consult Pure Turbos’ instructions for your specific variant.

  • Transfer any heat shields or brackets from the old turbos if the new kit does not include them. Most Pure kits are direct fit.
  • Apply a thin film of anti-seize to all threads that will contact the turbo housing (manifold bolts, V-band clamps).
  • Verify that all oil and coolant line fittings are clean and free of debris.

Step 3: Installing the Pure Turbos Stage 2 Turbos

Installation is essentially the reverse of removal, but with added care to avoid contaminating the oil system.

3A: Manifold and Turbo Assembly

  • Position a new OEM or upgraded gasket onto the cylinder head studs.
  • Set the manifold/turbo assembly into place. You may need to lift the engine slightly from underneath (using a block of wood on a jack) to gain clearance.
  • Hand-thread all manifold bolts before tightening. Torque to 18 ft-lb (25 Nm) in two passes, following the sequence in the BMW repair manual.

3B: Oil and Coolant Connections

  • Use new crush washers on the oil feed banjo bolts. Torque to 18 ft-lb (25 Nm). Do not overtighten – the oil feed lines are brittle.
  • Install the coolant hoses with new O-rings (if provided). Ensure the hoses are not kinked and clear of the exhaust.
  • Attach the oil return line with a new gasket. Torque to 10 ft-lb (14 Nm).

3C: Exhaust and Charge Pipes

  • Connect the downpipes to the turbo outlet with new V-band clamps. Torque to 35 ft-lb (47 Nm). Ensure the wastegate rod does not contact the downpipe.
  • Reinstall the charge air cooler and connect all charge pipes. Tighten worm-gear clamps to 4 Nm (35 in-lb) – plastic intercooler tanks can crack if overtightened.
  • Reconnect the intercooler coolant pump and fill the low-temperature coolant circuit with the correct G48 or G64 coolant.

Step 4: Reassembling Ancillary Systems

  • Install the intake air filter housings and sensors. Reconnect any vacuum lines that were disconnected (boost reference lines, diverter valve solenoids).
  • Refill the engine oil – use a high-quality synthetic with a robust add-pack. Do not start the engine yet.
  • Refill the main cooling system with BMW coolant mix. Leave the bleeder screw open at the highest point of the coolant pipe.

Step 5: Battery, Priming, and Leak Checks

  • Reconnect the battery negative terminal.
  • Prime the oil system: Disable the fuel pump (pull the fuel pump fuse or relay), then crank the engine for 10 seconds at a time (with 30-second rests) until the oil pressure warning light extinguishes. This ensures oil reaches the turbo bearings before combustion.
  • Re-enable the fuel pump and start the engine. Let it idle for 5 minutes. During this time, inspect for oil and coolant leaks at every connection. Pay special attention to the oil return lines – they are a common leak point after turbo swaps.
  • Check the BMW-specific bleeding procedure for the cooling system. Rev the engine to 2,500 RPM until the thermostat opens and coolant flows freely. Top off as needed.

Step 6: Initial Start-Up and Test Drive

  • Allow the engine to reach operating temperature. Listen for unusual noises – a whistling sound could indicate a boost leak; a metallic rattle may mean the wastegate is loose.
  • Check for fault codes using a scan tool (e.g., BimmerGeeks ProTool). Expect a few pending codes for disconnections; clear them after the first drive.
  • Take a short test drive (5 miles) under light throttle. Avoid heavy boost until the ECU has learned the new wastegate positions. After 20–30 miles, perform a few full-throttle pulls in 3rd gear to log fuel trims, boost pressure, and intake air temps. Share these logs with your tuner.

Post-Installation Tuning and Calibration

Pure Turbos Stage 2 turbos flow significantly more air than stock. Your engine management system must be recalibrated to prevent overboost, knock, or lean mixtures. Most tuners offer a specific map for this kit. Key adjustments include:

  • Boost target – Typically 20–22 psi on a conservative tune, 24–26 psi for race fuel or meth injection.
  • Wastegate duty cycle – Pure’s larger actuators require a recalibrated duty cycle table to avoid boost creep.
  • Fueling – Larger turbos demand increased fuel flow. You may need upgraded HPFP (Bosch 2200cc lpfp) and injectors (Motiv or or similar port injection).
  • Ignition timing – The tuner will pull timing from the mid-range to keep cylinder pressures safe under high boost.

Do not drive the car hard until the tune is finalized. Running the Stage 2 turbos on a stock tune can cause catastrophic overboost. If you cannot flash the ECU yourself, drive gently to your tuning shop.

Frequently Asked Questions

How long does the installation take?

For an experienced home mechanic, allow 10–15 hours total. First-timers should budget two full weekends – one for removal and one for installation and debugging.

Do I need upgraded injectors or a fuel pump?

It depends on your power goals. The Pure Stage 2 turbos can support up to 650 whp on E85 with a full fuel system. On pump gas at lower boost (550 whp), stock injectors are adequate, but the HPFP may still need upgrading if you see fuel pressure drop. Consult your tuner.

Will this kit pass emission tests?

No, not without a complex secondary air system and proper catalyst setup. The downpipes in the kit are typically catless. Emission legality varies by state. Check your local regulations before installing.

Can I reuse my old oil lines?

Pure Turbos recommends replacing all oil feed and return lines with new OEM parts. Old lines may contain debris that can damage the new turbo bearings.

What is the break-in procedure?

After installation and a short test drive, change the oil and filter. Drive for 500 miles under varied RPM (avoid sustained high load) before performing a full dyno pull. Some tuners suggest a brief break-in period for the turbo seals.

Conclusion

Installing the Pure Turbos Stage 2 M3 Turbo Kit is a major but manageable project that delivers impressive power gains when combined with proper tuning. By following the detailed steps in this guide—from preparation and stock turbo removal to careful reassembly and initial start-up—you can achieve a clean, reliable installation. Remember to invest time in thorough priming and leak checking, and always work with a tuner who is experienced with Pure Turbos hardware. The result is an M3 that pulls hard to redline with a linear, responsive torque curve that surpasses any factory turbocharger. With patience and attention to detail, you can transform your car into a true performance machine that you built yourself.

Always refer to the official Pure Turbos installation instructions for your specific kit version, and when in doubt, consult a certified BMW technician.