Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Service manual — part 154

IN(w/o STI)-15

Turbocharger

INTAKE (INDUCTION)

13) Disconnect the oil outlet hose from the oil outlet

pipe, and remove the turbocharger.

14) Remove the turbocharger stay.

B: INSTALLATION

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) Temporarily tighten the union bolts and flare

nuts which secure the oil inlet pipe to the turbo-

charger.
NOTE:

Use a new gasket.

(A) To cylinder head RH
(B) To cylinder block RH

(A) To cylinder head RH
(B) To cylinder block RH

IN-02310

IN-02859

(A)

(A)

(B)

T1

IN-02860

(A)

(A)

(B)

T2

IN-02310

IN-02938

IN-02937

IN(w/o STI)-16

Turbocharger

INTAKE (INDUCTION)

5) Tighten the union bolts and flare nuts which se-

cure the oil inlet pipe to the turbocharger.
CAUTION:

In order to prevent damaging the oil pipe on the

cylinder head side, fix the section (a) shown in

the figure when tightening the oil inlet pipe flare

nut, and avoid the part from rotating together

while tightening the nut.

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)

6) Connect the air control hose (A), and install the

intake duct to the turbocharger.
Tightening torque:

3 N·m (0.3 kgf-m, 2.2 ft-lb)

7) Connect the engine coolant hoses to the coolant

filler tank.

8) 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)

9) Lift up the vehicle.

10) Install the center exhaust pipe. <Ref. to

EX(STI)-9, INSTALLATION, Center Exhaust

Pipe.>

11) Lower the vehicle.

12) Install the intercooler. <Ref. to IN(w/o STI)-12,

INSTALLATION, Intercooler.>

13) Connect the battery ground terminal.

14) Fill engine coolant. <Ref. to CO(w/o STI)-13,

FILLING OF ENGINE COOLANT, REPLACE-

MENT, Engine Coolant.>

(a)

IN-02955

IN-02939

T1

T2

IN-02940

(A)

IN-02936

IN-02935

IN-00203

IN(w/o STI)-17

Turbocharger

INTAKE (INDUCTION)

C: INSPECTION

1. WASTE GATE ACTUATOR

1) Remove the intercooler. <Ref. to IN(w/o STI)-12,

REMOVAL, Intercooler.>

2) Remove the turbocharger upper cover.

3) 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).

4) Pressurize slowly with the Mighty Vac, and mea-

sure the pressure when the control rod stroke (D)

becomes 2 mm (0.08 in). If it is not within the stan-

dard, 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)

5) 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)

2. OTHER INSPECTIONS

1) Check that the turbocharger and pipe have no

deformation, cracks or other damages.

2) Check that the hose and intake duct have no

cracks, damage or loose part.

3) Check that there are no oil leakage or water

leakage from the pipe attachment section.

(A) Waste gate actuator
(B) Boost hose

(C) Control rod
(D) Control rod stroke

EX-02662

(C)

(B)

(A)

IN-02941

(D)

IN(w/o STI)-18

Air By-pass Valve

INTAKE (INDUCTION)

8. Air By-pass Valve

A: REMOVAL

Disconnect the air by-pass pipe (A) and vacuum

hose (B) from the air by-pass valve, and remove

the air by-pass valve from the intercooler.

B: INSTALLATION

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)

C: INSPECTION

1. AIR BY-PASS VALVE

1) Check that the air by-pass valve has no defor-

mation, cracks or other damages.

2) Connect the Mighty Vac to the nipple (A) of the

air by-pass valve.

3) Using the Mighty Vac, generate the negative

pressure to –93.3 kPa (–0.95 kgf/cm

2

, –13.5 psi).

Check that the Mighty Vac gauge needle holds 10

seconds without falling by –92.6 kPa (–0.94 kgf/cm

2

,

–13.4 psi).

4) Set a dial gauge to the end of valve rod of the air

by-pass valve.

5) Using the Mighty Vac, generate the negative

pressure, and check the pressure when dial gauge

needle (valve stroke) shows 0.5 mm (0.02 in). If it is

not within the standard, replace the air by-pass

valve.
Opening pressure (valve stroke 0.5 mm (0.02

in)):

Standard

–53.3 — –61.3 kPa (–0.54 — –0.63 kgf/cm

2

,

–7.73 — –8.89 psi)

6) Generate the additional negative pressure from

5), and check the pressure when dial gauge needle

(valve stroke) shows 7.5 mm (0.3 in). If it is not with-

in the standard, replace the air by-pass valve.
Full open pressure (valve stroke 7.5 mm (0.3

in)):

Standard

–93.4 — –108 kPa (–0.95 — –1.10 kgf/cm

2

,

–13.5 — –15.7 psi)

2. OTHER INSPECTIONS

Check that the vacuum hose and air by-pass pipe

have no cracks, damage or loose part.

IN-03076

(A)

(B)

IN-02604

(A)

IN-02605