StraightGate40 Pneumatic pSG40 External Wastegate by Turbosmart
Turbosmart StraightGate40 Pneumatic (pSG40) 40mm Butterfly External Wastegate
The Turbosmart StraightGate40 Pneumatic is the smallest butterfly-style external wastegate on the market — designed for tight engine bays without compromising boost control authority.
Unlike traditional poppet-style 40mm wastegates, the StraightGate40 uses a zero-offset butterfly valve, allowing exhaust gas to flow straight through the body for increased efficiency and improved control characteristics.
Compact in size. Massive in flow capability.
Why the StraightGate40 Exists
Traditional 40mm poppet wastegates are often limited by:
• 90-degree exhaust flow turns
• High drive pressure sensitivity
• Limited tuning window
• Packaging compromises
The StraightGate40 solves this by using a centrally pivoting butterfly valve that allows straight-through exhaust flow.
Flow rating:
• 217.4 CFM
• 6.16 m³ per minute
That’s exceptional for a compact 40mm package.
Self-Balancing Butterfly Design
The zero-offset butterfly valve is exposed to exhaust drive pressure evenly across both halves of the valve.
This creates a self-balancing effect.
Unlike traditional wastegates that must fight rising drive pressure at high boost levels, the StraightGate40 requires less actuator force to remain stable.
The benefits:
• Reduced actuator load
• Improved high boost stability
• Wider usable tuning window
• More consistent boost control
Even in high backpressure applications.
Pneumatic Boost-Based Control (pSG40)
The Boost-Based Pneumatic StraightGate40 simplifies control using a traditional GenV boost-based actuator.
Pre-fitted with 6 psi springs and compatible with both single and twin port boost control, the pSG40 offers:
• Simple mechanical boost control
• Compatibility with standard boost controllers
• Wide tuning flexibility
• Over 5x base spring pressure tuning window
You get advanced butterfly architecture without electronic complexity.
StraightGate40 vs Traditional 40mm Wastegates
StraightGate40:
• Straight-through flow
• Butterfly valve
• Self-balancing under drive pressure
• Massive tuning window
• Compact packaging
Traditional 40mm poppet gate:
• 90-degree exhaust turn
• More actuator load under high drive pressure
• Narrower effective control window
They are not the same product category.
Ideal Applications
The StraightGate40 is suited to:
• Tight engine bay installations
• High-mount turbo setups
• Small to medium frame turbochargers
• High drive pressure systems
• Builders wanting maximum control in minimal space
It is especially effective where packaging constraints limit the use of larger butterfly gates.
Key Technical Features
• 40mm (1.57in) zero-offset butterfly valve
• 217.4 CFM / 6.16 m³ per minute flow
• Stainless Steel (630) butterfly and shaft
• Stainless Steel (347) main body
• Heat-treated 431 stainless steel V-band clamps
• Aluminium (6262 T6 anodised) actuator bracket
• Turbosmart locking collar ring
• Base spring options from 6 psi to 42 psi
• Suitable for single or twin port boost-based control
• Nitronic 60 stainless steel linkages and control arm
Designed and validated in-house by Turbosmart.
Frequently Asked Questions
What makes the StraightGate40 different from a normal 40mm wastegate?
The StraightGate40 uses a straight-through butterfly valve instead of a poppet valve, significantly improving flow efficiency and stability under high drive pressure.
Is it better than a CompGate40?
They are different designs.
The CompGate40 is a traditional poppet-style wastegate.
The StraightGate40 offers higher flow efficiency and improved control in high backpressure environments due to its butterfly architecture.
Can I use a normal boost controller?
Yes.
The pSG40 supports both single and twin port boost-based control, making it compatible with conventional boost control systems.
How much boost can it handle?
Spring options range from 6 psi to 42 psi base pressure.
Due to the self-balancing design, the usable tuning window exceeds 5 times base spring pressure, depending on system configuration.
Why Buy From Walton Motorsport?
We understand how drive pressure, collector design and turbo sizing influence wastegate performance.
Butterfly-style wastegates like the StraightGate40 solve problems traditional poppet gates cannot — particularly in high backpressure or compact installations.
If you’re unsure whether a traditional 40mm gate or the StraightGate40 is right for your system, contact us before ordering.
Boost control is system engineering — not just component selection.
