Turbos, Wastegates, BOV's & Controllers
A motorcycle turbo system can start very basic and work quite well when the demands are low. But increase the demands or want more finite control, this article is for you.
Preface
There are two basic types of riders using turbos. One, is the drag racer who wants to put as much coal to the fire as possible and thus needs fine tuning from the gear box, engine and turbo. Two, is the performance street guy who wants the turbo for a nip of extra power or for bragging rights and/or racing other fast bikes.
As a point of interest, anything more than 250rwhp on a street bike is just going to spin the tire in any gear, even 6th. Remember, drag strips have special sticky surfaces that grip that power more effectively. Yet, through the act of controlling the boost, one can be much more effective in how the boost comes on. The first level of controlling boost is feathering the boost so the wheel does not spin (olde school). The next level, is to use any number in a wide variety of boost controllers.
However, many if not most street turbo riders, simply put a basic turbo kit on with an internal wastegate, get their 230-250rwhp and are very content with that. After all more stuff, means more cost and more fine tuning. The only issue they have to be very careful with using a basic install, is to not over boost.
Mastering the Art of Turbo Systems: A Technical Story
In the world of high-performance engines, turbocharging is a key technology that significantly boosts power and efficiency. The heart of this technology lies in the intricate dance between various components, including turbo wastegates, blow off valves (BOVs), and turbo controllers. This article delves into the technical aspects of these components, explaining how they work together to optimize turbocharged systems.
The Turbocharger: Core of the System
A turbocharger comprises a turbine and a compressor connected by a shaft. Exhaust gases from the engine spin the turbine, which in turn drives the compressor to draw in and compress more air into the engine's intake manifold. This increased air intake allows for more fuel to be burned, producing greater power output.
Wastegates: Regulating Exhaust Flow
The wastegate is a critical component that regulates the flow of exhaust gases to the turbine, thereby controlling the turbocharger's boost pressure. There are two main types of wastegates: internal and external.
Internal Wastegates:
Design: Built into the turbocharger housing, internal wastegates use a bypass valve to divert some exhaust gases away from the turbine.
Operation: Controlled by a pneumatic actuator, which is connected to the intake manifold. When the boost pressure reaches a predetermined level, the actuator opens the wastegate, allowing excess exhaust gases to bypass the turbine.
Pros and Cons: Internal wastegates are compact and simpler to install but may have limitations in handling very high boost pressures.
External Wastegates:
Design: Separate from the turbocharger, external wastegates use a diaphragm and spring mechanism to control exhaust gas flow.
Operation: Like internal wastegates, they are controlled by a pneumatic actuator. However, they offer more precise control and can handle higher boost pressures, making them ideal for high-performance applications.
Pros and Cons: External wastegates provide better control and durability but require more space and complex installation.
Blow Off Valves (BOVs): Protecting the Turbo System
Blow Off Valves play a vital role in maintaining the health and performance of a turbocharged engine by preventing compressor surge. Compressor surge occurs when the throttle is suddenly closed, causing a rapid build-up of pressure in the intake system. This backpressure can stall the turbo compressor wheel, leading to potential damage and reduced efficiency.
How BOVs Work:
Pressure Detection: Installed between the turbocharger and the throttle body, the BOV continuously monitors intake manifold pressure.
Activation: When the throttle is closed, creating a vacuum in the intake manifold, the BOV is triggered.
Release Mechanism: The valve opens to vent excess pressure either to the atmosphere (atmospheric BOV) or back into the intake system (recirculating BOV), thus preventing compressor surge.
Types of BOVs:
Atmospheric BOVs: Vent excess pressure to the atmosphere, producing a distinctive "whoosh" sound. Popular among enthusiasts for the auditory feedback.
Recirculating BOVs: Vent excess pressure back into the intake system, maintaining a more stable air-fuel mixture and reducing noise. Preferred for smoother engine operation.
Turbo Controllers: Precision Boost Management
Below find more information on Precision Boost Management and some relative videos…