Turbocharger Replacement

Overview

This guide walks you through replacing a turbocharger, such as the K27, on your Porsche 944 S2 with its 3.0L naturally aspirated engine, assuming an aftermarket turbo setup has been installed. While the S2 doesn’t come with a factory turbo, this procedure adapts the process for enthusiasts adding a turbocharger. It’s a detailed job requiring the removal of several components, but with mechanical know-how, it’s manageable. The turbo boosts engine performance, and proper installation ensures reliability. Tips for fitting a K27 turbo, including modifications, are included.

Tools Required

• Jack stands or ramps
• 10mm (3/8 inch) open-end wrench
• 10mm socket, ratchet, and 6-inch (152mm) extension
• 12mm socket
• 13mm socket and ratchet
• 15mm combination wrench
• 15mm socket
• 17mm socket and ratchet or 17mm wrench
• 19mm open-end wrench
• Thin-head 24mm (15/16 inch) open-end wrench
• 5mm Allen head socket or hex key
• Long 6mm Allen head socket or long 6mm hex key
• Medium flat-tip screwdriver
• Flat-tip jeweler’s screwdriver or straight probe
• Phillips head screwdriver
• Catch rags
• Drain pans

Parts Required

• Turbocharger Outlet Flange Seal Ring 944 111 205 03
• Turbocharger Inlet Flange Seal Ring 944 111 205 04
• Turbocharger Outlet Pipe to Cat Pipe Flange Seal Ring 944 111 205 03
• Turbocharger Supply Line O-Ring (top of turbocharger) 999 707 043 00
• Turbocharger Oil Discharge O-Ring (bottom of turbo to motor mount) 900 174 058 40
• Turbocharger Oil Inlet Flange O-Ring (top of bearing housing) 999 707 043 00
• Turbocharger Oil Supply Line Banjo Bolt Seal Rings (2 needed) N 013 814 8

Required Additional Procedures

Steps in these procedures are required to complete this process:

• Air Filter Housing and Air Flow Sensor Removal and Installation
• Allen Head and Cheesehead Bolt Removal
• Fuel Injector and Fuel Rail Removal and Installation
• Intake Manifold Removal and Installation
• Coolant System Draining, Filling, and Venting

Step-by-Step Procedure

Step 1: Prepare the Vehicle

1. Disconnect the negative battery cable to ensure safety while working.
2. Lift the car using jack stands or ramps for easy access underneath.

Step 2: Remove Air and Fuel Components

3. Remove the air filter housing and air flow sensor. Follow this link to ensure this step – Air Filter Housing and Air Flow Sensor Removal and Installation – is followed accurately.
4. Loosen the clamps on the intercooler outlet pipe (to the throttle body), disconnect the hoses on both sides, and remove the pipe.
5. Pull off the rubber inlet plenum boot from the turbocharger inlet. For a K27 turbo, you may need to modify this boot or use an adapter due to the larger inlet size.
6. Take out the fuel rail and injectors. Follow this link to ensure this step – Fuel Injector and Fuel Rail Removal and Installation – is followed accurately.
7. Remove the intake manifold. Follow this link to ensure this step – Intake Manifold Removal and Installation – is followed accurately.

Step 3: Drain Coolant and Remove Cooling Components

8. Remove the belly pan under the car.
9. Drain the coolant system. Follow this link to ensure this step – Coolant System Draining, Filling, and Venting – is followed accurately. Use drain pans to catch the fluid.
10. Remove the alternator air supply hose.
11. Disconnect the turbocharger cooling pump electrical connector (near the shock tower), loosen the 10mm (3/8 inch) nut at the strut tower holding the pump bracket, and remove the 10mm bolt behind the master cylinder heat shield. Slide the bracket off and disconnect the coolant hoses to remove the pump.

Step 4: Access the Turbocharger

12. (Optional) Remove the master cylinder heat shield for easier access, though it’s not required.
13. Loosen the heat shield between the turbocharger and engine block to access the 19mm banjo bolt for the oil supply line. Remove the bolt carefully, keeping the seal rings (N 013 814 8) intact.
14. Remove the two 15mm bolts securing the other end of the oil supply line.
15. Disconnect the cooling supply and return lines from the turbocharger.
16. Unbolt the turbocharger exhaust flange from the exhaust system.
17. Under the car, remove the steering shaft universal joint heat shield.
18. Loosen the four bolts holding the steering rack to the front cross-member to lower it slightly, giving access to the lower turbo mounting bolt.
19. Remove the bolts from the turbocharger outlet pipe triangle flange (above the O2 sensor) and the M8 bolt attaching it to the engine block.
20. From under the motor mount bracket, remove the two 6mm Allen head bolts holding the turbocharger. “Wake up” the bolts first to avoid stripping them. Follow this link to ensure this step – Allen Head and Cheesehead Bolt Removal – is followed accurately. You may need to lift the engine slightly with a jack for clearance.

Step 5: Remove the Turbocharger

22. Lift the turbocharger out of the car. The outlet pipe will stay attached during removal.

Step 6: Install the New Turbocharger

23. Attach the exhaust-side outlet pipe to the new turbocharger (e.g., K27), using a new flange seal ring (944 111 205 03).
24. Place a new O-ring (900 174 058 40) in the groove on top of the motor mount for the oil outlet seal.
25. Set a new seal ring (944 111 205 04) in the turbocharger inlet flange groove, using a dab of grease to hold it.
26. Carefully lower the turbocharger onto the motor mount, avoiding excessive movement to protect the O-ring. Tighten the two 6mm Allen bolts to 20 Nm (15 ft-lbs).
27. Reinstall the steering universal joint heat shield.
28. Tighten the turbocharger inlet flange bolts to 25 Nm (18 ft-lbs).
29. Install the oil supply line with a new O-ring (999 707 043 00) at the turbo flange and new seal rings (N 013 814 8) for the 19mm banjo bolt.
30. Reattach the balance shaft housing heat shield and its bolts.
31. Secure the turbocharger downpipe triangle flange to the block with its M8 bolt.
32. Connect the cooling water supply line and reinstall the turbocharger cooling pump.
33. Reinstall the master cylinder heat shield if removed.
34. Attach the turbocharger cooling pump to the heat shield.
35. Fit the inlet plenum boot. For a K27, reshape the cooling water outlet line if it contacts the larger housing, and check the temperature sensor clearance.
36. Install the cooling water outlet line and plug in the coolant temperature sensor.
37. Tighten the downpipe triangle flange bolts to 25 Nm (18 ft-lbs).

Step 7: Reassemble Remaining Components

39. Install the intake manifold. Follow this link to ensure this step – Intake Manifold Removal and Installation – is followed accurately.
40. Install the fuel injectors and fuel rail. Follow this link to ensure this step – Fuel Injector and Fuel Rail Removal and Installation – is followed accurately.
41. Install the air flow sensor and air filter housing. Follow this link to ensure this step – Air Filter Housing and Air Flow Sensor Removal and Installation – is followed accurately.
42. Fill and vent the cooling system. Follow this link to ensure this step – Coolant System Draining, Filling, and Venting – is followed accurately.

Post Procedure Checklist

• Check for oil or coolant leaks around the turbocharger connections.
• Ensure the cooling pump operates and no air is trapped in the system.
• Verify the inlet plenum boot is secure and adapted correctly (especially for K27).
• Start the engine and listen for unusual noises from the turbo.

Sources

• Clark’s Garage
• Pelican Parts
• Porsche 944 Workshop Manual, Volume 1
• YouTube