Category Archives: JDM

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.

Limited Spoiler 07 STi install:

Limited Spoiler 07 STi install:

This is a step by step guide in installing the Limited Spoiler from a 07 STi.

Here is the limited spoiler, already painted to match the lid:

The part number is actually E7210FE900 and the kit cost $221 shipped at the time of purchase, but prices may have changed.

Limited Spoiler 07 STi install: Here is the spoiler already painted and ready to install.
Limited Spoiler 07 STi install: Here is the spoiler already painted and ready to install.

1.)From the factory this fitting is already installed in the center of the spoiler, if you bought it unpainted, remove this BEFORE you get your spoiler painted. It just makes it easier. I simply cut the nipple off so that nothing is protruding from the bottom of the spoiler. You can also use the nipple and cut a hole in your trunk.

Limited Spoiler 07 STi install: Limited Spoiler 07 STi install: If you bought it unpainted, remove this BEFORE you get your spoiler painted.
Limited Spoiler 07 STi install: If you bought it unpainted, remove this BEFORE you get your spoiler painted.

2.) The 3M tape you want to use looks like this, I picked it up at the local auto parts/auto body shop. You can see the part number in the picture. It costs around $15 and you will have enough for two or more installations.

The 3M tape you want to use looks like this, I picked it up at the local auto parts/auto body shop. You can see the part number in the picture.
The 3M tape you want to use looks like this, I picked it up at the local auto parts/auto body shop. You can see the part number in the picture.

You can buy the 3M Tape here:


3M(TM) Automotive Acrylic Plus Attachment Tape 06384, Black, 1/2 In X 5 Yds, 45 mil [PRICE is per ROLL]

Steering Systems on early Subarus Part 1

Steering Systems on early Subarus Part 1:

Rack And Pinion Steering Mechanism

Subaru steering systems utilize a rack and pinion steering mechanism. As the pinion gear rotates, the rack moves left or right. Rack and pinion steering gives the driver precise control over the wheels. The simple, compact design is easy to service.

Steering Systems on early Subarus Part 1: The Subaru SVX used Subaru's early power steering system.
Steering Systems on early Subarus Part 1: The Subaru SVX used Subaru’s early power steering system.

CGR – VGR Ratios

Two manual steering racks are used in Subaru vehicles: a constant gear ratio (CGR) rack and a variable gear ratio (VGR) rack. The teeth on the CGR rack are equally spaced so the turning effort is equal throughout the turning range. The teeth on the VGR rack are spaced closer together on the ends of the rack than in the middle. The turning effort decreases as the turning angle increases so sharp-radius turns are easier to make.

Legacy and SVX Steering Racks

Several different power steering racks have been installed in Subaru vehicles. The racks used in the L-series, XT, Legacy and SVX vehicles are similar. All have a one-piece gearbox and lack the external air vent distribution tube found on the rack in pre-’85 and carryover vehicles. However, the XT rack differs from the L-series rack in several ways.

The XT rack is made of aluminum and has a different control valve. Different types of hydraulic seals are used in the two racks, and each has its own unique special service tool. The power steering rack in the pre-’85 model year vehicles and the Brat has a two-piece gearbox and an air vent distribution tube. It also has seals, service procedures and special service tools that differ from the other racks.

Rigid Steering Column

Three types of steering columns are used in Subaru vehicles: a rigid steering column, a tilt steering column and the XT and SVX tilt and telescoping steering column. The rigid steering column is found on L-series DL models, the Legacy standard model, and Justy vehicles. The rigid steering shaft does not tilt or pop-up, but is collapsible (a safety feature). The shaft is connected to the gearbox by universal joints.

ABS 5.3 Antilock Brake System for Early Subaru Part 5:

ABS 5.3 Antilock Brake System for Early Subaru Part 5:

 

ABS 5.3 Antilock Brake System for Early Subaru Part 5: Beginning in approximately December of 1996, a new antilock braking system called ABS 5.3 was installed on Legacy vehicles equipped with ABS.
ABS 5.3 Antilock Brake System for Early Subaru Part 5:
Beginning in approximately December of 1996, a new antilock braking system called ABS 5.3 was installed on Legacy vehicles equipped with ABS.

 

Beginning in approximately December of 1996, a new antilock braking system called ABS 5.3 was installed on Legacy vehicles equipped with ABS. This system uses a Bosch hydraulic control unit and a Nippon electronic control unit. ABS 5.3 is a four channel control design which can independently control the front wheels and utilize select low control to control the rear wheels (a system which provides the same fluid pressure control for the two rear wheels if either wheel starts to lock up).

Although similar to other Subaru ABS systems, there have been enhancements to component operation and location. Diagnosis has also improved because of the ability of the 5.3 ABS system to communicate with the Select Monitor. The hydraulic control unit or HCU is located under the hood on the right side of the engine compartment. The size of the HCU has decreased by approximately a third from that of the ABS-2E system, used on previous model year vehicles.

The HCU controls brake fluid flow by utilizing eight solenoid valves. There is an inlet solenoid valve and an outlet solenoid valve for each wheel. Mechanically, the inlet solenoid valve is open during normal braking, and the outlet solenoid valve is closed. The HCU also contains a motor and pump assembly, which operates only while ABS is actively controlling the brake fluid flow–preventing a wheel lock.

Beginning in approximately December of 1996, a new antilock braking system called ABS 5.3 was installed on Legacy vehicles equipped with ABS.
ABS 5.3: Beginning in approximately December of 1996, a new antilock braking system called ABS 5.3 was installed on Legacy vehicles equipped with ABS.

Externally the HCU of the ABS 5.3 has a relay box attached. This allows troubleshooting of the valve and motor relay area to be kept separate from the troubleshooting of the solenoid valves and pump motor. There are four modes of operation for the ABS 5.3 system. They are normal, pressure-drop, pressure-hold and pressure-increase. When wheel lockup is sensed, Mode Two, Mode Three and Mode Four may be activated. They are described as follows:

Wastegate and Boost Creep FAQ

Wastegate and Boost Creep FAQ

What is Boost Creep?

Boost creep is a situation where your wastegate port is not large enough to allow the exhaust gas to bypass the turbo. What happens is the exhaust gas will choke the wastegate port preventing further gas flow through the port. Then, the exhaust gas has to take the path of least resistance which is through the turbine of the turbo. This will spool the turbo ‘uncontrolled’ beyond your normal controlled max boost level.

Wastegate and Boost Creep FAQ: A stock Subaru turbo with the internal wastegate and stock actuator.
Wastegate and Boost Creep FAQ: A stock Subaru turbo.

The turbo will be spooling past wastegate spring rate pressure even though the wastegate is fully open thus it is uncontrolled. The best way to check for boost creep is to connect the turbo outlet port directly to the wastegate actuator port and go for a drive. In 4th gear you should normally get a stable boost level of about 0.5 BAR, if you have boost creep the boost will hit 0.5 BAR and will continue to rise with rpm until you either back off or hit overboost fuel cut.

Boost creep should only be present on a turbo that has very little restriction. For example a fully de-catted and high flow induction. It’s been found that the fast spooling IHI VF35 is very prone to boost creep. The cure is to remove the turbo and enlarge the wastegate port. Then, fit a stronger actuator 0.75 BAR the reason for this is because you have made the wastegate port larger. The effective size of the wastegate plate acting against the exhaust gas flow is larger which allows the exhaust gas excert more force on the wastegate plate.

This in effect weakens the effectiveness of the actuator. Before the increase in size of your wastegate port the actuator would open at 0.5 BAR, after the increase the actuator would open earlier at 0.3–0.4 BAR. After these changes are made to the turbo either a boost controller or a remap (to adjust solenoid duty cycle) should be sought to control the boost to a safe level.

Boost control systems on a Turbo Subaru:

Boost control system on a Turbo Subaru:

This guide covers most  boost related issues including a short introduction on how your boost systems work. This information is based on the Classic Impreza’s, but will cover the newer WRX/STi cars to a certain extent.

Safe boost levels:

When modding your car without mapping (full de-cat and high flow induction etc) you increase the efficiency of your turbo which could result in engine damage due to lean running at high rpm / max boost. To prevent damage always try and keep your boost level as close to standard as possible until your car is mapped for the increase in boost pressure.

TLDR: Don’t screw with your boost levels until you get the car tuned by someone who knows what they are doing. Otherwise you’ll probably end up with a blown up Subaru.

Boost Issues:

Is the boost control system connected correctly:

ABS for Early Subaru Part 4:

ABS Brake System for Early Subaru Part 4:

Troubleshooting Process:

To troubleshoot ABS systems, it’s best to follow a step-by-step procedure like the one on the 1992 Legacy ABS-2E Service Manual Supplement. Enter the flow diagram with the symptom reported on the repair order.

ABS Brake System for Early Subaru Part 4: The Subaru Legacy RS was known for using this ABS System.
ABS Brake System for Early Subaru Part 4: The Subaru Legacy RS was known for using this ABS System.

The diagram calls that Trouble Occurs. The first step in the procedure is “Basic Checks.” This calls for a visual inspection to look for obvious problems and includes the following items:

• improper battery voltage
• low brake fluid level
• brake fluid leaks
• brake drag
• condition of the brake pads and rotors
• size, type, and condition of the tires (Check the tires to confirm that they are the correct tires for the vehicle, that they are in good condition, and that they are inflated to the correct pressure).

If you find something wrong at this stage, correct it and see whether it eliminates the reported symptom. If not, continue to Step 3. Step 3 is Self-diagnosis. At this time, put the ECU into self-diagnostic mode, and monitor the ABS warning lamp for trouble codes.

Headlight aiming basics for Subarus:

Headlight aiming basics for Subarus:

Subaru models equipped with aerodynamic headlights require no special fixtures for headlight alignment. Each headlight is equipped with a built-in headlight aiming mechanism. The following sequence demonstrates the correct technique for adjusting the headlights on a Subaru Legacy equipped with aerodynamic headlights.

Headlight aiming basics for Subarus: Some basic headlight adjusting techniques for Subaru cars.
Headlight aiming basics for Subarus: Some basic headlight adjusting techniques for Subaru cars.

1.) Turn off the headlight before adjusting headlight aiming. If the light is necessary to check aiming, do not turn on the headlights for more than two minutes.

2.) Inspect the area around the headlight for any damage. If the vehicle has been involved in an accident, it may not be possible to properly adjust the headlights until the damage has been professionally repaired.

3.)The vehicle must be parked on level ground and all four tires must be properly inflated.