Tag Archives: GD

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.

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.

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.

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.

JDM Automatic Intercooler STi Switch Install:

JDM Automatic Intercooler STi Switch Install:

Here is the step by step guide to installing the JDM Automatic Intercooler STi switch. For those of you wondering the advantage of upgrading to the JDM automatic intercooler switch is that it essentially works as a on/off switch for the STi intercooler sprayer. So there is no more constant pushing of the sprayer button. Push the button once to turn it on, and again to turn it off. However, it will empty out your intercooler sprayer tank very quickly if you keep it on.

Here is the switch we are going to be installed:

JDM Automatic Intercooler Switch: The JDM intercooler switch that you will be installing.

1.) Pop out the fuse box panel. The fuse box panel is located underneath and to the left of the steering wheel.

2.) Use your fingers to depress the tab on the button of the button to pop it out.

JDM Automatic Intercooler Switch: The USDM stock STi switch that you will be removing.

3.) Pull the switch out of the dash.

4.) Depress the tab on the back of the plug to remove the switch.

JDM Automatic Intercooler Switch: USDM STi intercooler switch removed. Get ready to install the JDM switch now.

Maintenance:Subaru Periodic Maintenance Part 1:

Maintenance: Subaru Periodic Vehicle Maintenance Services:

Vehicle maintenance is an important factor for proper vehicle operation. It’s the vehicle owner’s responsibility to ensure that fluid levels (engine oil, coolant, etc.) are checked frequently, in accordance with the instructions in the Subaru owner’s manual. However, many ‘gas and go’ vehicle owners may not take the time to fulfill these basic responsibilities. This places added importance on the performance of periodic maintenance services. If the Subaru owner isn’t looking after his vehicle, it falls to the automotive service professional to ensure that proper maintenance procedures are performed.

Maintenance: Subaru Periodic Vehicle Maintenance: It’s always important to periodically check your Subaru’s timing belt for wear and tear.

The frequency of scheduled inspection and maintenance services required by late model Subaru vehicles is minimal when compared with vehicles of the past. For example, even the very commonly used term ‘tune-up’ has lost most of its original meaning. In the old days, a ‘tune-up’ meant fresh spark plugs, points and condenser, and basic engine adjustments such as timing, idle mixture and idle speed. Modern technology has eliminated the need for many of these adjustments and replacement parts. However, the tune-up is alive and well— only its definition has changed.

While the number of vehicle items requiring regular replacement has decreased, the number of items needing periodic inspection has not. Whether you call it a tune-up or something else, this service offers an excellent opportunity for all engine belts, hoses and ignition wires to be checked for wear and tension. Old tune-up standbys like spark plugs, fuel and air filters are still on every Subaru vehicle and still require periodic inspection and replacement as necessary.

The same applies to all other items on the Subaru maintenance schedule. The important thing is to carefully inspect each item. If additional corrective action is required, now is the time to find out.