Category Archives: STi

Drivetrain, Ej20, EJ257, gc8, Impreza, JDM, Legacy, STi, Subaru, Turbo, USDM, WRX

Cool Down WRX Turbo Procedure

Cool Down WRX Turbo Procedure:

It is not necessary to perform a cool down/idling procedure on Subaru WRX turbo models, as was recommended with past turbo models. “The current 2.0 liter turbo engine has a far greater cooling capacity and, coupled with technology advances, makes this practice no longer necessary. This explains why information about a cool down is not included in the Impreza Owner’s Manual.

Cool Down WRX Turbo Procedure: It is not necessary to perform a “cool down/idling” procedure on Subaru WRX turbo models, as was recommended with past turbo models.
Cool Down WRX Turbo Procedure: It is not necessary to perform a “cool down/idling” procedure on Subaru WRX turbo models, as was recommended with past turbo models.

The heat contained in the turbocharger begins to vaporize the coolant at the turbocharger after the engine is stopped. This hot vapor then enters the coolant reservoir tank, which is the highest point of the coolant system.

At the same time the vapor exits the turbocharger, coolant supplied from the right bank cylinder head flows into the turbo. This action reduces the turbocharger temperature. This process will continue until the vaporizing action in the turbocharger has stopped or cooled down.

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2.5RS, Drivetrain, Ej20, EJ25, EJ257, forester, Impreza, STi, Subaru, Turbo, USDM, WRX

Engine noise when cold (Winter is coming)

Engine Noise When Cold:

Beginning with the 1997 model year, the 2.2 and 2.5 engines were made more fuel efficient, more powerful, and were given a flatter, more usable torque curve than in previous years. To achieve these objectives, it was necessary to make improvements and modifications to the Subaru engine lineup. The following are some of those improvements:

• Mechanical valve lash adjusters (reduces friction).
• Lightweight pistons (reduces inertia).
• Short skirt, Molybdenum coated pistons (reduces friction).
• Increased compression ratio (improved power output).
• Improved cylinder head design (improved cooling).
• Improved induction system (improved breathing).

Engine Noise when cold: As a result of these enhancements, some Subaru engines may exhibit some engine noise during the warm-up period after a cold startup.
Engine Noise when cold: As a result of these enhancements, some Subaru engines may exhibit some engine noise during the warm-up period after a cold startup.

As a result of these enhancements, some Subaru engines may exhibit some engine noise during the warm-up period after a cold startup. This engine noise is a consequence of the engine improvements and is not, in any way, an indication of any engine problem.

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2.5RS, AWD, DCCD, Drivetrain, forester, gc8, Impreza, JDM, Legacy, STi, Subaru

AWD: The five types of Subaru systems

AWD: The five types of Subaru systems

Back in 1972, Subaru introduced the Leone 4WD Station Wagon. It was the first fourwheel drive vehicle designed specifically for everyday driving, rather than for off-road or rugged use.The safety and driving performance aspects of the Leone 4WD proved popular and made the car successful. It quietly set the standard for Subaru to become the global AWD leader of today.

AWD Genesis: The safety and driving performance aspects of the Leone 4WD proved popular and made the car successful.
AWD Genesis: The safety and driving performance aspects of the Leone 4WD proved popular and made the car successful.

 

Subaru Symmetrical All-Wheel Drive:

Subaru calls its system of mating a horizontally opposed (boxer) engine to various types of full-time AWD “Symmetrical All-Wheel Drive.” This system is based on the balance of both the powertrain and the straight, nearly-horizontal, flow of power to the wheels.The weight of the flat boxer engine and the transfer components lie very low in the chassis, providing a lower center of gravity, resulting in excellent traction and stability.

The Five Types of Subaru Symmetrical All-Wheel Drive:

Subaru currently uses five different types of Symmetrical AWD. Each is specific to the Subaru model and transmission.The five types are:

■ Continuous All-Wheel Drive
■ Active All-Wheel Drive
■ Variable Torque Distribution (VTD) All-Wheel Drive.
■ Driver Controlled Center Differential (DCCD) All-Wheel Drive
■ Vehicle Dynamics Control (VDC) All-Wheel Drive

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2.5RS, AWD, Drivetrain, forester, gc8, Impreza, Legacy, STi, Tuning, Turbo, USDM, WRX

OBD-II Subaru Diagnostic Systems

OBD-II Subaru Diagnostic Systems:

The Environmental Protection Agency (EPA) now has regulations in place that establish requirements for on-board diagnostic (OBD-II) systems on light-duty vehicles and light-duty trucks. The purpose of the OBD-II system is to ensure proper emission control system operation for the vehicle’s lifetime by monitoring emission-related components and systems for deterioration and malfunction.

OBD-II Subaru Diagnostic Systems: The Environmental Protection Agency (EPA) now has regulations in place that establish requirements for on-board diagnostic (OBD-II) systems on light-duty vehicles and light-duty trucks.
OBD-II Subaru Diagnostic Systems:
The Environmental Protection Agency (EPA) now has regulations in place that establish requirements for on-board diagnostic (OBD-II) systems on light-duty vehicles and light-duty trucks.

There’s a big difference between detecting only hard faults (OBD-I) and having the ability to actively monitor the system for proper operation, deterioration or a malfunction (OBD-II).

Engines in today’s vehicles are largely electronically controlled. Sensors and actuators sense the operation of specific components (e.g., the oxygen sensor) and actuate others (e.g., the fuel injectors) to maintain optimal engine control. An on-board computer, known as the “powertrain control module,” controls all of these systems.

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forester, gc8, Impreza, Legacy, STi, Subaru, USDM, WRX

Part Number Decoder Subaru

Part Number Decoder:

For those of you who are interested, this is how Subaru breaks down a part number. This could help you guess a part number if one that you found on a part is missing digits or is damaged.

Part number decoder for Subaru: For those of you who are interested, this is how Subaru breaks down a part number.
Part number decoder for Subaru: For those of you who are interested, this is how Subaru breaks down a part number.

Genuine Part Classification Codes

A = Part Description Code
B = Part Sequential Code
C = Part Category Code
D = Specific Code
E = Modification Code
F = Color Code

Description of Genuine Part Classification Codes

A. Part Description Code: Identifies part name and function. If the first position is an alpha, it identifies an accessory.

B. Part Sequential Code: Sequential number system assigned to the part number by Fuji Engineering Division.

C. Part Category Code: Key position of the part number in determining the logic of the numbering system:
A = Engine and Transmission Parts
K = Engine and Transmission Parts
X = Some Automatic Transmission Parts
G = Body Parts

D. Specific Parts: Identifies specific characteristics of parts with the same part description code and designated sequences from A00. The specific code is assigned by the Fuji Engineering Division for internal use only.

E. Modification Code: Identifies an engineering change to the part. For example:
0 = original
1 = 1st modification
2 = 2nd modification
3 = 3rd modification

F. Part Color Code: Identifies color coded parts for digits 11 and 12. Digit 11 = color and digit 12 = degree.
Code E or F in the 12th digit is for Fuji Heavy Industries (FHI) internal purposes only.

Note: Code E or F in the 12th digit is for Fuji Heavy Industries (FHI) internal purposes only.

For example look at these rare 22B parts with their part numbers.

Part Name Part Number Quantity
22B Bolt Subaru 57728FA041 2
22B Bush B (L/Link) 20251AA050 1
22B Bushing Transverse Link Front ST2022044000 1
22B Bushing Transverse Link Rear ST2022044010 1
22B Clip Subaru 57728FA020 6
22B Fender 57110FA050 1
22B Fog Lamp Cover Set (LH and RH) S075580070 1 Set
22B Front Bumper Assembly S075580080 1
22B J Nut 57738KA000 2
22B Lateral Link Assy-F S075580140 1
22B Lateral Link Assy Rear RH S075580150 1
22B Lateral Link Assy Rear LH S075580160 1
22B License Plate Bracket S075580210 1
22B Pillow Ball Bushing 20252PA000 1
22B Seat Right Front 64101FA680 1
22B Seat Left Front 64101FA690 1
22B Seat Rear Cushion 64401FA410 1
22B Seat Rear Seatback 64451FA810 1
Drivetrain, forester, gc8, Impreza, Legacy, STi, Subaru, WRX

R-134a A/C refrigerant guide

R-134a A/C refrigerant guide for Subaru cars:

Since 1996, original equipment manufacturers have been using R-134a in all automotive air conditioning systems. R-134a is now the refrigerant of choice. This short article will help you learn proper safety procedures regarding the use of R-134a. Also, to stress the importance of refrigerant identification for OEM automotive A/C systems, we will explain some of the specific system component changes, and discuss important changes to A/C service equipment.

You may already be familiar with R-134a, A/C retrofits, and proper procedures. If you are confident of your abilities and retrofit knowledge, try answering the 20 question quiz that ends this article. If you are not sure about your R-134a retrofit knowledge, read this article first.

R-134a A/C refrigerant guide for Subaru cars: Since 1996, original equipment manufacturers have been using R-134a in all automotive air conditioning systems. R-134a is now the refrigerant of choice.
R-134a A/C refrigerant guide for Subaru cars:
Since 1996, original equipment manufacturers have been using R-134a in all automotive air conditioning systems. R-134a is now the refrigerant of choice.

What Is R-134a?

R-134a does not contain suspected ozone-depleting chlorofluorocarbons. The chemical compounds and molecular structures of the old refrigerant R-12 and the new refrigerant R-134a are completely different. However, the temperature/pressure relationships of the two are very similar. Automotive publications, equipment manufacturers, and refrigerant suppliers, provide technical specifications and properties for R-134a.

R-134a and R-12 are not compatible. Under no circumstances should they be mixed. Vehicle and service manufacturers have gone to great lengths to prevent cross-charging or contamination of these two refrigerants. For instance, R-12 systems use a small high-side service port, and a large low-side service port. R-134a service fittings are completely different. The high side service port is now the larger of the two. These quick disconnect fittings will not work with R-12 service equipment.

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2.5RS, Drivetrain, Ej20, ej20G, EJ25, EJ257, forester, gc8, Impreza, JDM, STi, Subaru, Turbo, UK, USDM, WRX

Subaru Engine Block Piston Size Identifier:

Subaru Engine Block Piston Size Identifier:

The picture below of this paragraph shows the location of piston size and main journal size information on all Subaru engines. As the figure illustrates, it is possible to have more than one piston size in the same engine.

Subaru Engine Block Piston Size Identifier: The picture on the bottom shows the location of piston size and main journal size information on all Subaru engines. As the figure illustrates, it is possible to have more than one piston size in the same engine.
Subaru Engine Block Piston Size Identifier:
The picture on the bottom shows the location of piston size and main journal size information on all Subaru engines. As the figure illustrates, it is possible to have more than one piston size in the same engine.
2.5RS, forester, gc8, Impreza, STi, Subaru, UK, USDM, WRX

Electrical Grounding System inspection

Electrical Grounding System inspection:

The importance of checking electrical ground connections during any electrical troubleshooting cannot be over stressed. For example, a poor electrical ground at the radiator support or fender (depending on the affected Subaru model) may cause any or all of the following problems:

• The door ajar indicator light dims when the brake pedal is applied.

• There is a loss of communication with the Automatic Transmission side of the New Select Monitor when the vehicle is put into gear.

• The engine starts running poorly after driving only a few feet.

• There is a loss of communication with the Anti-lock Brake side of the New Select Monitor when the brake pedal is applied.

Vehicles that have been involved in accidents should be inspected especially closely. In the example below, a Subaru Legacy had been involved in a front end collision.

During reassembly of the vehicle, the electrical ground wire behind the left front headlight that fastens to the radiator support had not been reinstalled (refer to photo). This electrical ground is attached to the left front fender on Subaru Impreza and Forester models. After reinstalling this ground wire, all of the affected systems returned to proper working order.

Electrical Grounding System inspection: The importance of checking ground connections during any electrical troubleshooting cannot be over stressed.
Electrical Grounding System inspection: The importance of checking ground connections during any electrical troubleshooting cannot be over stressed.