Engine Intake System (H4DOTC) (except Sti) Subaru Impreza WRX STI GR

Scheme 302

Tightening torque: N.m (kgf-m, ft-lb)

T1: 1 (0.1, 0.7)

T2: 2.5 (0.3, 1.8)

T3: 6 (0.6, 4.4)

T4: 7.5 (0.8, 5.5)

Scheme 303

Tightening torque: N.m (kgf-m, ft-lb)

T1: 6.4 (0.7, 4.7)

T2: 17 (1.7, 12.5)

T3: 19 (1.9, 14.0)

Scheme 304

Tightening torque: N.m (kgf-m, ft-lb)

T1: 6.5 (0.7, 4.8)

T2: 16 (1.6, 11.8)

TURBOCHARGER

1. Except for WRX-SS model

Scheme 305

Tightening torque: N.m (kgf-m, ft-lb)

T1: 5 (0.5, 3.7)

T2: 8.8 (0.9, 6.5)

T3: 16 (1.6, 11.8)

T4: 20 (2.0, 14.8)

T5: 23 (2.3, 17.0)

T6: 33 (3.4, 24.3)

1. WRX-SS model

Scheme 306

Tightening torque: N.m (kgf-m, ft-lb)

T1: 4.9 (0.5, 3.6)

T2: 6.5 (0.7, 4.8)

T3: 16 (1.6, 11.8)

T4: 20 (2.0, 14.8)

T5: 23 (2.3, 17.0)

T6: 33 (3.4, 24.3)

CAUTION

1. Wear appropriate work clothing, including a cap, protective goggles and protective shoes when performing any work.
2. Remove contamination including dirt and corrosion before removal, installation or disassembly.
3. Keep the disassembled parts in order and protect them from dust and dirt.
4. Before removal, installation or disassembly, be sure to clarify the failure. Avoid unnecessary removal, installation, disassembly and replacement.
5. Vehicle components are extremely hot after driving. Be wary of receiving burns from heated parts.
6. Be sure to tighten fasteners including bolts and nuts to the specified torque.
7. Place shop jacks or rigid racks at the specified points.
8. Before disconnecting connectors of sensors or units, be sure to disconnect the ground cable from the battery.

GENERAL TOOL

GENERAL TOOL CHART

Scheme 307

Scheme 308

1. Disconnect the ground cable from battery.
2. Remove the air intake duct. Ref. to «REMOVAL»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/mechanical/#engine-intake-system-h4dotc-except-sti) , Air Intake Duct.
3. Disconnect the connector from air flow and intake air temperature sensor.
4. Remove the clip (B) from the air cleaner case (front).
5. Open the air cleaner case, and remove the air cleaner element.

Scheme 309

INSTALLATION

Install in the reverse order of removal.

Note. Check that there are no foreign objects in the air cleaner case.

INSPECTION

Replace if excessively damaged or dirty.

Scheme 310

Scheme 311

1. Disconnect the ground cable from battery.
2. Remove the air intake duct. Ref. to «REMOVAL»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/mechanical/#engine-intake-system-h4dotc-except-sti) , Air Intake Duct.
3. Disconnect the connector from air flow and intake air temperature sensor.
4. Loosen the clamp (B) which connects the air intake boot and intake duct.
5. Remove the clip (C) from the air cleaner case (front).
6. Remove the air cleaner case (rear) and air intake boot.
7. Remove the air cleaner element.
8. Remove the bolt (A) and-nut (B) which secure the air cleaner case (front) to the body.
9. Remove the air cleaner case (front).

Scheme 312

Scheme 313

1. Install the bolt (A) and nut (B) which secure the air cleaner case (front) to the body. Tightening torque: Bolt (A) 6 N.m (0.6 kgf-m, 4.4 ft-lb) Nut (B) 7.5 N.m (0.8 kgf-m, 5.5 ft-lb)
2. Install the air cleaner element.
3. Install the air cleaner case (rear) and air intake boot. NOTE: When installing the air cleaner case (rear), align the protrusion of the air cleaner case (rear) to the hole on the air cleaner case (front) to install. Tightening torque: 2.5 N.m (0.3 kgf-m, 1.8 ft-lb)
4. Install the clip (B) to the air cleaner case (front).
5. Connect the connector (A) to the mass air flow and intake air temperature sensor.
6. Install the air intake duct. Ref. to «INSTALLATION»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/mechanical/#engine-intake-system-h4dotc-except-sti) , Air Intake Duct.
7. Connect the ground cable to battery.

Check for cracks or loose connections.

REMOVAL

Remove the clip which secures the air intake duct, and remove the air intake duct.

Scheme 314

Install in the reverse order of removal.

1. Check for cracks or loose connections.
2. Inspect that no foreign objects in the air intake duct.

1. Disconnect the ground cable from battery.
2. Remove the intake manifold. Ref. to «REMOVAL»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/fuel-system/#fuel-injection-system-h4dotc) , Intake Manifold.
3. Remove the sensor, engine harness and fuel pipe attached to the intake manifold. Ref. to «DISASSEMBLY»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/fuel-system/#fuel-injection-system-h4dotc__disassembly) , Intake Manifold.
4. Remove the intake duct from intake manifold.

Scheme 315

Install in the reverse order of removal.

Tightening torque

17 N.m (1.7 kgf-m, 12.5 ft-lb)

Scheme 316

Scheme 317

Scheme 318

1. Disconnect the air by-pass pipe (A) and vacuum hose (B) from the air by-pass valve.
2. Loosen the clamp (C) which connects the intercooler and intake duct.
3. Remove the bolts which secure the intercooler to the turbocharger.
4. Remove the bolts which secure the intercooler to the intercooler stay, and remove the intercooler.
5. Remove the brake booster vacuum hose from the clip (A), and remove the intercooler stay.

Scheme 319

Install in the reverse order of removal.

Note. Use new O-rings. Be careful not to pinch the O-ring.

Tightening torque

16 N.m (1.6 kgf-m, 11.8 ft-lb)

Scheme 320

Tightening torque

3 N.m (0.3 kgf-m, 2.2 ft-lb)

Scheme 321

DISASSEMBLY

1. Remove the air by-pass valve from intercooler.

Scheme 322

ASSEMBLY

Assemble in the reverse order of disassembly.

Note. Use new O-rings. Be careful not to pinch the O-ring.

Tightening torque

6.5 N.m (0.7 kgf-m, 4.8 ft-lb)

Check for cracks or loose connections.

Scheme 323

Scheme 324

Scheme 325

Scheme 326

Scheme 327

Scheme 328

Scheme 329

Scheme 330

1. Set the vehicle on a lift.
2. Disconnect the ground cable from battery.
3. Lift up the vehicle.
4. Drain approximately 3.0 C (3.2 US qt, 2.6 Imp qt) of coolant. Ref. to «DRAINING OF ENGINE COOLANT»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/cooling-system-mechanical/#engine-cooling-system-h4dotc-except-sti) , REPLACEMENT, Engine Coolant.
5. Lower the vehicle.
6. Remove the intercooler. Ref. to «REMOVAL»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/mechanical/#engine-intake-system-h4dotc-except-sti) , Intercooler.
7. Remove the center exhaust pipe. Ref. to «REMOVAL»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/exhaust/#exhaust-system-exhaust-h4dotc-except-sti) , Center Exhaust Pipe.
8. Lower the vehicle.
9. Remove the joint pipe from the turbocharger.
10. Disconnect the engine coolant hoses from coolant filler tank.
11. Disconnect the air control hose (A), and loosen the clamp holding the turbocharger to the intake duct. Except for WRX-SS model WRX-SS model
12. Remove the oil inlet pipe from the turbocharger. Except for WRX-SS model WRX-SS model
13. Disconnect the engine coolant hose from the water pipe.
14. Disconnect the oil outlet hose from the oil outlet pipe, and remove the turbocharger.
15. Remove the turbocharger stay.

Scheme 331

Scheme 332

Scheme 333

Scheme 334

1. Install the turbocharger stay. Tightening torque: T1:33 N.m (3.4 kgf-m, 24.3 ft-lb) T2:42.5 N.m (4.3 kgf-m, 31.3 ft-lb)
2. Connect the oil outlet hose to the oil outlet pipe.
3. Connect the engine coolant hoses to the water pipe.
4. Install the oil inlet pipe to turbocharger. Except for WRX - SS model Tightening torque: T1: 5 N.m (0.5 kgf-m, 3.7 ft-lb) T2: 16 N.m (1.6 kgf-m, 11.8 ft-lb) T3: 20 N.m (2.0 kgf-m, 14.8 ft-lb) WRX-SS model Tightening torque: T1: 16 N.m (1.6 kgf-m, 11.8 ft-lb) T2: 20 N.m (2.0 kgf-m, 14.8 ft-lb)
5. Connect the air control hose (A), and install the turbocharger to the intake duct. Tightening torque: 3 N.m (0.3 kgf-m, 2.2 ft-lb) Except for WRX-SS model WRX-SS model
6. Connect the engine coolant hoses to the coolant filler tank.
7. Install the joint pipe to turbocharger. NOTE: Replace the gasket with a new part. Tightening torque: 42.5 N.m (4.3 kgf-m, 31.3 ft-lb)
8. Lift up the vehicle.
9. Install the center exhaust pipe. Ref. to «INSTALLATION»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/exhaust/#exhaust-system-exhaust-h4dotc-except-sti) , Center Exhaust Pipe.
10. Lower the vehicle.
11. Install the intercooler. Ref. to «INSTALLATION»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/mechanical/#engine-intake-system-h4dotc-except-sti) , Intercooler.
12. Connect the ground cable to battery.
13. Fill engine coolant. Ref. to «FILLING OF ENGINE COOLANT»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/cooling-system-mechanical/#engine-cooling-system-h4dotc-except-sti) , REPLACEMENT, Engine Coolant.

Scheme 335

Scheme 336

Scheme 337

1. Except for WRX-SS model Remove the intercooler. Ref. to «REMOVAL»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/mechanical/#engine-intake-system-h4dotc-except-sti) , Intercooler. Remove the turbocharger upper cover. Remove the boost hose (B) from the waste gate actuator (A) of the turbocharger, and connect the Mighty Vac to the waste gate actuator (A). Pressurize slowly with the Mighty Vac, and measure the pressure when the control rod stroke (D) becomes 1 mm (0.04 in). If it is not within the standard, replace the turbocharger assembly. CAUTION: Do not pressurize over 56.0 kPa (0.57 kgf/cm 2 , 8.12 psi) to prevent damaging the waste gate actuator. Operating pressure (Control rod stroke 1 mm (0.04 in)): Standard 44.0 - 46.6 kPa (0.45 - 0.48 kgf/cm 2 , 6.38 - 6.76 psi) After inspection, install the related parts in the reverse order of removal. Tightening torque: 7.5 N.m (0.8 kgf-m, 5.5 ft-lb)

Scheme 338

1. WRX-SS model Remove the intercooler. Ref. to «REMOVAL»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/mechanical/#engine-intake-system-h4dotc-except-sti) , Intercooler. Remove the turbocharger upper cover. Remove the boost hose (B) from the waste gate actuator (A) of the turbocharger, and connect the Mighty Vac to the waste gate actuator (A). Pressurize slowly with the Mighty Vac, and measure the pressure when the control rod stroke (D) becomes 2 mm (0.08 in). If it is not within the standard, replace the turbocharger assembly. CAUTION: Do not pressurize over 89.9 kPa (0.92 kgf/cm 2 , 13.0 psi) to prevent damaging the waste gate actuator. Operating pressure (Control rod stroke 2 mm (0.08 in)): Standard 74.7 - 80.8 kPa (0.76 - 0.82 kgf/cm 2 , 10.8 - 11.7 psi) After inspection, install the related parts in the reverse order of removal. Tightening torque: 7.5 N.m (0.8 kgf-m, 5.5 ft-lb)

OIL PIPE AND WATER PIPE

1. Check that there are no oil leakage or water leakage from the pipe attachment section.
2. Check for cracks or loose connections.

1. Disconnect the air by-pass pipe (B) and vacuum hose (C) from the air by-pass valve (A).
2. Remove the air by-pass valve (A) from the inter-cooler.

Scheme 339

Install in the reverse order of removal.

Note. Use new O-rings. Be careful not to pinch the O-ring.

Tightening torque

6.5 N.m (0.7 kgf-m, 4.8 ft-lb)

Scheme 340

See also:
• REMOVAL
• DISASSEMBLY
• DRAINING OF ENGINE COOLANT
• REMOVAL
• REMOVAL