Boost Control Systems Explained. Part 2 PERRIN Performance Official Blog. How do you get more boost than the spring pressure in the wastegateIn Part 1, we describe the basics on how your boost control system works and the components involved. Some of the diagrams in Part 1 were common items found on stock turbocharged engines, and some only found on aftermarket turbo systems. In both setups, its possible get more boost from your turbo, than the wastegate spring pressure. This is done by using different methods to change the boost signal getting to the wastegate actuator. Part 2 of Boost Control Systems Explained will hit on the most common ways of doing this. In order to get more boost than the spring pressure in the wastegate actuator, pressure needs to be bled off or blocked from the hose going to the wastegate actuator. This in turn delays when the wastegate will start to open and control boost. How do you get more boost than the spring pressure in the wastegate In Part 1, we describe the basics on how your boost control system works and the components involved. Auto Parts and Truck Part for Car and Automotive parts. How to read the engine diagnostic code The following applied to a 2004 Nissan Altima but I believe any Nissan uses this method. The Service Engine Soon light will. Think of this as tricking the wastegate as to what boost its seeing. Boost pressure can be bled off in a few ways, using a mechanical bleeder type system with a needle and a seat, a small opening or bleed hole, or the more reliable and accurate way using an electromechanical solenoid. Manual Boost Controllers. Starting with one of the simplest forms of boost control, lets look at a Manual Boost Controller. These are mechanical devices that are set manually and have no feedback and are not connected to the ECU in any way. Manual boost controllers are simple, cost effective ways to increase boost. But they are not perfect. How does our PERRIN Manual Boost Controller work  There are 4 main components to it, the body, stem, spring and ceramic ball. Boost enters the body but is blocked by the ceramic ball. The spring behind the ball keeps the boost from getting past the ball. Install Root Enumerated Driver Live Suit Pack. Adjusting the tension on the spring adjusts when boost pressure pushes the ball off its seat. When the ball moves off its seat, the boost flows through the boost controller and actuates the wastegate actuator. The ball simply delays when the boost gets to the actuator. The adjustment to when the ball lifts effecting boost is the tension on the spring. IWG75-3-Port-MAC-800x610.png' alt='How To Install A Boost Solenoid Actuator' title='How To Install A Boost Solenoid Actuator' />In our design, the stem gets screwed in and out of the body which changes the spring pressure on the ball. One key thing to our MBC Manual Boost Controller is our bleed hole. In the stem is a bleed hole that serves 2 purposes. One is to relieve pressure from behind the ball, when the turbo is not making boost. If this wasnt there the wastegate would be stuck open after the first time it made boost. The second purpose is to bleed some of the volume of air flowing through the MBC. This helps with keeping a steady boost curve that doesnt drop off severely at higher RPM. You can see the install is very simple. Hose in on one side and out the other This above diagram is showing an external type wastegate, but same thing applies for an internal type wastegate. For most customers its about 1. The downfall is there is nothing controlling the boost. With a manual type boost controller there are some variables to the actual boost achieved. Temp out side, temp of the exhaust manifold, load on the engine all effect the actual boost level. This means from day to day, or even road to road, you can see a fluctuation in boost. For some customers, its not a problem as they have had their ECU tuned to account for the different levels. The problem is that your car can have varying performance, which not everyone likes. Also at part throttle, you can get get full boost almost full power. This is also not a desired feeling as it removes some of the modulation of power. Most cars when stock are setup to deliver half the power at half the throttle. That way as you roll past half throttle, you add more boostpower, making the car more drivable. Power can be great, but if its like a switch, that can be hard to handle in corners Overall the Manual boost controller is cheap and easy to install, and its adjustable by anyone with a boost gauge. Those are great benefits for some customers, and a Manual Boost Controller shouldnt be overlooked when deciding how you should increase boost on your car. Electronic Boost Control Solenoids. A solenoid is a simple valve that is mechanically opened or closed when battery voltage is applied to it. This is done using a coil winding surrounding a ferrous metal actuator. The battery voltage passes through the coil and causes a magnetic field which moves an actuator that pulls open a valve. Crazy House Chess. Typically these are setup to bleed air from the hose going to the wastegate actuator. Keep in mind, the solenoid doesnt work as on off as describe, in fact the valve is turned on and off very fast to vary the amount of pressure bled from the hose. The speed and length the valve is opened, effects how much pressure is being bled off thus effecting boost. This process isnt self contained in the solenoid, but rather driven by the ECU engine control unit in your car, or sometimes by aftermarket controllers. This above diagram shows a typical solenoid  used for boost control at rest and also with voltage applied to it. The blue represents the coil that when engergized creates the magnetic field. The Green represents the ferrous metal, the red represents the valve being actuated and the orange arrows indicate the air flowing. As mentioned above, the speed and length at which the ECU turns the solenoid on and off, effects the amount of air being bled and when the wastegate actuator actually opens. The ECU produces this pulsing on and off signal in based on tables in the ECU and many calculations. This pulsing signal is commonly known as the wastegate duty cycle. This duty cycle is a percentage of how long the solenoid is open for a given time. Because the solenoid can open and close only so fast, it has a normal operating frequency. The frequency is how many times it can operate in 1 second, referred to as hertz not the rent a car company. Typically solenoids work in the 1. ECU is changing to increase boost. Back to the duty cycle. The duty cycle is a calculated a percentage of time the solenoid is actually open. Meaning 5. DC Duty Cycle means the solenoid on for 5. The more time the solenoid is on, the more air is bled from the system, and in turn the longer the wastegate is delayed from opening. One second of time show above. This example shows a solenoid working at 5hz turning on and off 5 times in 1 second and then shows 2. This allows you to visualize the amount of time the solenoid is actually open at different duty cycles. NOTE the 1. The ECU can vary this duty cycle signal to the wastegate solenoid to vary the boost higher or lower, to account for temp changes, atmospheric pressure changes, provide a steadier boost curve and even cut boost in situations when a failure has occurred. The ECU has many special mapstables that determine the DC to use to control boost. This includes target boost tables, min and max DC tables, Boost error trim tables, air temp trims, speed trims gear trims and many more. The ECU uses these with a complicated algorithm to calculate duty cycle and then adjust it to reach its target boost. Here is an example of how this works and an example of the diffent typs of maps used to control boost. If the ECU sees the driver giving 7. RPM it reads a map that says it needs to hit 1. The ECU starts with a duty cycle of say 5. Say it only hits 1. ECU knows its off by 3psi and adds more duty cycle based on a boost error trim table.