Turbosmart Electronic StraightGate40 (eSG40) 40mm Butterfly External Wastegate

The Turbosmart eSG40 is not a boost-controlled wastegate.

It is a fully electronically actuated exhaust flow control device.

No springs.
No diaphragms.
No reference hoses.

The Electronic StraightGate40 replaces traditional pneumatic control with a precision servo motor and zero-backdrive gearbox, allowing direct ECU-driven boost control with unmatched authority and tuning range.

Compact in size. Unlimited in control potential.

Why Electronic Actuation Changes Everything

Traditional wastegates are limited by:

• Base spring pressure
• Diaphragm stability
• Reference signal accuracy
• Drive pressure influence

The eSG40 removes those limitations.

The integrated servo motor directly positions the zero-offset butterfly valve, allowing:

• Boost control from zero boost (manifold priority dependent)
• Maximum boost control authority
• Wider tuning window than any pneumatic gate
• Instant electronic response
• No spring swapping

This is the widest effective tuning window available in a 40mm wastegate format.

Zero-Offset Butterfly Architecture

At its core, the eSG40 uses the same zero-offset butterfly valve found in the StraightGate platform.

The 40mm centrally pivoting butterfly:

• Is exposed evenly to drive pressure
• Self-balances under exhaust load
• Requires less actuation force
• Maintains stability at extreme backpressure

Flow rating:

• 217.4 CFM
• 6.16 m³ per minute

Combined with electronic control, this creates a level of precision traditional poppet gates cannot achieve.

Zero-Backdrive Gearbox

The servo motor drives the valve through Turbosmart’s zero-backdrive gearbox.

This design:

• Prevents exhaust pressure from forcing the valve open
• Reduces current demand
• Maintains stable valve position
• Improves control accuracy under extreme drive pressure

It’s designed specifically for motorsport-level abuse.

Integrated Sensor Suite

The eSG40 includes onboard monitoring for:

• Actuator temperature (0–5V analog output)
• Valve position (0–5V analog output)
• PWM digital valve position output

This provides ECU visibility into:

• Thermal conditions
• Real-time valve position
• Control strategy feedback

It is not just a wastegate — it’s a controllable exhaust valve with data output.

Ideal Applications

The Electronic StraightGate40 is suited to:

• Advanced standalone ECU systems
• Motorsport applications requiring full boost strategy control
• Anti-lag and launch control strategies
• Variable boost mapping by gear, speed or torque target
• High drive pressure turbo systems

If you want spring-based boost control, this is not the product.

If you want programmable exhaust bypass control — this is it.

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
• 360° V-band mounting options
• Clockable actuator position (3 x 120° options)
• Full electronic actuation (Dual H-Bridge input)
• Onboard 0–5V actuator temperature sensor
• Onboard 0–5V analog valve position sensor
• Onboard PWM digital valve position sensor
• 7-wire unterminated flying lead loom
• Liquid cooling provision for actuator stability

Patent pending design.

Frequently Asked Questions

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Does the eSG40 require boost reference hoses?

No.

The eSG40 is fully electronically actuated and does not use springs, diaphragms or boost reference lines.

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Can it run zero boost?

Potentially yes — if your manifold priority and turbo configuration allow full bypass.

Electronic control allows the widest possible tuning window.

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What ECU do I need?

You will require an ECU capable of:

• Dual H-Bridge output control
• Monitoring 0–5V sensor inputs
• Configuring electronic wastegate strategies

Standalone motorsport ECUs are typically required.

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Is it better than a pneumatic StraightGate40?

It depends on your control strategy.

The pneumatic version offers mechanical simplicity.

The electronic version offers maximum programmability and tuning precision.

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Why Buy From Walton Motorsport?

We don’t just sell parts — we design turbo systems.

Electronic wastegate control requires understanding:

• Drive pressure ratios
• Manifold priority
• Control strategy mapping
• ECU configuration

If you are considering the eSG40, you’re likely building a serious system.

If you need support choosing between pneumatic and electronic control, speak to us before ordering.