Choosing Between IWG or EWG

Wastegates are critical for regulating boost pressure by controlling the flow of exhaust gases into the turbo; therefore, you must carefully choose between internal wastegated (IWG) turbocharger or external wastegate (EWG) turbocharger.

Internal Wastegates (IWG)

Design

IWGs use an actuator to control the boost output and divert excess gases from the turbine wheel. They are integrated within the turbocharger housing.

Advantages:

•  Compactness: Due to their integrated design, it saves more space for engine bays with limited room. Usually applied on OEM applications.
•  Cost Effectiveness: IWG is much easier to install and is less costly than an EWG due to fewer components.
• Emissions Compliance: Often designed to meet emission standards as they direct exhaust gases through the catalytic converter in the exhaust system.
• Stable Performance: Fewer setup parts lead to less failure points. For example, external wastegate diaphragms wear out faster especially on those turbos without water-cool. IWGs also response faster than EWGs.

Disadvantages:

• Limited Flow Capacity: Smaller valve size tends to restrict exhaust flow, leading to potential boost creep at higher boost levels.
• Less Precise Control: Comparably less effective in maintaining stable boost pressure especially in high-performance scenarios.

External Wastegates (EWG)

Design

Mounted separately from the turbocharger, usually on the exhaust manifold or downpipe/up-pipe, they control boost pressure by venting excess exhaust gases out, requires more piping than IWGs.

Advantages:

• Superior Boost Control: Bigger valve sizes allow for more precise regulation of exhaust gases, effectively preventing boost creep and especially better in high performance applications.

• Enhanced Performance: EWGs can reduce backpressure by efficiently diverting exhaust gases, potentially increase power output, therefore better suited for higher boost levels.

• Flexibility: Due to separate unit, they offer more flexibility in terms of valve sizing and location. They can vent exhaust gases out to the atmosphere or back into the exhaust system, and allow for adjustable spring rates, catering to specific performance needs.

Disadvantages:

• More Complex: EWGs require additional components modifications, therefore are more complex in installation.

• Higher Cost: More costly due to extra parts and labor for installation, may involve additional fabrication which costs more.

• Space Requirement: EWGs require more room in the engine bay for installation.

• Noise Levels: When setup is to vent to the atmosphere, it can result in louder exhaust sounds, which may not be desirable for all users.

Choosing Between IWG and EWG

• Application: An IWG is more suitable for daily driving or moderate performance enhancements. An EWG usually applies on high-performance or racing applications requiring precise boost control with higher boost levels.

• Budget Considerations: IWGs are less costly and easier to install; while EWGs involve higher costs due to more complex installation processes, but EWGs offer superior performance.

• Noise Consideration: Venting to the atmosphere cause EWGs to be significantly louder than IWGs, although routing the wastegate back into the exhaust system can mitigate the loudness of the sound.

Choosing between IWG and EWG depends on the specific performance goals, budget, and application requirements of the vehicle. Usually IWGs are more suitable for standard applications with space and cost constraints, while EWGs provide superior boost control and performance for high-performance needs, although more costly and complex.