Wastegate Removal and Installation

Introduction

Removing the wastegate from a 944 Turbo is a genuinely difficult job. There is no straightforward approach — tight clearances, deeply recessed bolts, and overlapping pipe flanges all combine to make the job awkward. Understanding the mounting arrangement fully before starting will help you plan the best approach for your specific situation.

Wastegate Mounting Arrangement

The wastegate diaphragm attaches to the valve body with three Allen head bolts (6 mm hex) that pass up through the valve body and through the bottom flange of the diaphragm. One bolt threads into a nut tack-welded to the diaphragm flange; the other two pass through the flange and thread into bolts tack-welded to the wastegate mounting bracket. The other end of the mounting bracket is bolted around the torque tube with two 13 mm head bolts.

The discharge pipe has a flange bolted to the valve body with four 13 mm head bolts, and is additionally secured to the torque tube bracket by one 13 mm bolt. The other end connects to the main exhaust pipe at a flange with two 10 mm bolts.

The inlet pipe mounts to the valve body with a four-stud flange and connects at its other end (near the crossover pipe) via a triangle flange with three 10 mm bolts.

Known difficulties:

1. Both the inlet and discharge pipe flanges insert several inches into their mating connections. Even with the wastegate unbolted from the torque tube bracket, one of the pipes must be removed to extract the assembly.
2. Removing the inlet pipe while the assembly is in the car is impractical without removing the inlet flange studs — not recommended given the tight working space.
3. The discharge pipe bolts have heads too close to the flange to accept a standard socket — the socket must be modified.
4. Moving the discharge pipe enough to clear the wastegate body after unbolting is awkward.
5. The wastegate mounting bolts at the torque tube are very difficult to access.

Tools

• 13 mm socket (modified — see step 4)
• Ratchet
• Universal joint for socket
• 6" socket extension
• 10 mm socket and 10 mm wrench, or two 10 mm wrenches
• Pry bar
• Flat-tip screwdriver
• 8 mm socket or wrench
• 17 mm wrench
• 6 mm hex key or long 6 mm Allen head socket

Removing the Wastegate

1. Place the car on ramps or jack stands.
2. Remove the 8 mm nut on the back of the starter heat shield. Loosen (do not remove) the two bolts on the side of the clutch housing holding the shield. Slide the heat shield off the starter and set aside.
3. Using a flat-tip screwdriver, loosen the wastegate diaphragm hose clamp and disconnect the actuating hose from the diaphragm.
4. Remove the wastegate discharge pipe. The flange bolts (4 × 13 mm) have insufficient clearance for a standard socket. Grind down the outer diameter of the open end of a 13 mm socket on a bench grinder until it fits in the recesses. Use the modified socket with a universal joint and 6" extension to access the more difficult bolts. Remove all four discharge flange bolts.
5. Using the 13 mm socket, also remove the single bolt attaching the discharge pipe flange to the torque tube mounting bracket.
6. Remove the two flange bolts at the other end of the discharge pipe (10 mm).
7. Using the pry bar, slide the discharge pipe toward the torque tube and down toward the starter motor. Once the flange clears the wastegate valve body, remove the discharge pipe.
8. Disconnect the triangle-shaped flange bolt on the inlet pipe (3 bolts, 10 mm).
9. Locate the two wastegate diaphragm Allen head bolts securing the wastegate mounting bracket. Remove them using the 6 mm hex key or long 6 mm Allen head socket.
10. Slide the wastegate off the mounting bracket and out of the car with the inlet pipe still attached.

Installing the Wastegate

1. With the inlet pipe attached to the wastegate, slide the end of the inlet pipe into the crossover pipe flange and attach the wastegate to the mounting bracket with the two Allen head bolts. Torque to 20 Nm (14 ft-lb) using the 6 mm hex key or Allen socket. Torque the inlet pipe to crossover pipe triangle flange bolts to 8 Nm (6 ft-lb) using 10 mm socket and wrench or two 10 mm wrenches.
2. Install the wastegate discharge pipe. Torque the four discharge flange bolts and the discharge pipe to torque tube bracket bolt to 20 Nm (14 ft-lb) using the modified 13 mm socket. Torque the discharge pipe to main exhaust pipe flange bolts to 8 Nm (6 ft-lb) using 10 mm socket and wrench.
3. Connect the wastegate actuating hose and tighten the hose clamp.