Understanding Automotive Performance Wastegate Sizing

Understanding Automotive Performance Wastegate Sizing

When it comes to enhancing automotive performance, one crucial component is the wastegate. Proper wastegate sizing ensures optimal turbocharger efficiency, longevity, and overall engine performance. Let's delve into the nuances of wastegate sizing and why it's essential for your vehicle.

What is a Wastegate?

A wastegate is a device within turbocharged engines that controls the flow of exhaust gases to the turbocharger. Its primary function is to regulate the engine’s boost pressure by diverting excess exhaust gases away from the turbine wheel. This prevents the turbo from over-speeding, which could lead to engine damage.

Importance of Proper Wastegate Sizing

Correct wastegate sizing is critical because it directly affects how efficiently your turbocharger operates. An improperly sized wastegate can lead to issues such as:

  1. Boost Creep: This occurs when the wastegate cannot divert enough exhaust gases, causing the turbo to generate more boost than desired.
  2. Boost Spike: This is a sudden surge in boost pressure, which can be damaging to the engine.
  3. Insufficient Boost Control: A wastegate that's too large may cause issues in maintaining the desired boost pressure, especially at lower RPMs.

Factors Influencing Wastegate Sizing

Several factors must be considered to determine the appropriate wastegate size for your setup:

  1. Engine Size and Power Output: Larger engines producing more power typically require larger wastegates.
  2. Turbocharger Size: The size and efficiency of your turbocharger will influence the amount of exhaust gas needing diversion.
  3. Boost Pressure Targets: Higher boost levels require more precise control, influencing the size and type of wastegate needed.
  4. Exhaust Flow Characteristics: This includes considerations like the type of exhaust manifold and whether the system is single or twin-scroll.

External vs. Internal Wastegates

There are two main types of wastegates: external and internal.

  • Internal Wastegates: Built into the turbocharger, internal wastegates are simpler and more compact but may not provide as precise control in high-performance applications.
  • External Wastegates: Mounted separately from the turbo, external wastegates offer better control, especially in high-boost scenarios, making them preferred for performance and racing applications.

Wastegate Sizing Guidelines

A general guideline for wastegate sizing is:

  • For engines with less than 400 horsepower, a 38mm wastegate is usually sufficient.
  • For engines between 400-600 horsepower, a 44mm wastegate is typically recommended.
  • For engines producing over 600 horsepower, a 50mm or larger wastegate may be necessary.

These guidelines are not absolute, as the specific application and tuning requirements can influence the ideal size.

Why Choose Turbosmart Wastegates from PLM?

At PLM, we understand the importance of high-quality components in achieving peak automotive performance. That's why we carry Turbosmart wastegates, known for their exceptional build quality, reliability, and performance. Turbosmart offers a range of wastegates designed to meet various performance needs, ensuring you get the best possible boost control for your turbocharged setup.

By choosing a Turbosmart wastegate from PLM, you benefit from:

  • Precision Engineering: Ensures accurate boost control and reliability.
  • Durability: Built to withstand the harsh conditions of high-performance environments.
  • Versatility: Available in various sizes to suit different power levels and applications.


Proper wastegate sizing is essential for any turbocharged vehicle aiming for optimal performance. By considering factors such as engine size, turbocharger specifications, and desired boost levels, you can select the appropriate wastegate for your needs. At PLM, we recommend Turbosmart wastegates for their superior performance and reliability, ensuring you get the most out of your turbocharged engine.

Upgrade your turbo setup with a Turbosmart wastegate from PLM and experience the difference in performance and control.

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