V-IWG Wastegate Actuator Suits Mk8 Fiesta ST FORD – 4inHg

What is the first rule of boost control?
Ensure you have an overboost cut-out. This safety feature is built into all factory, aftermarket & programmable ECUs. You can never be too careful. Make sure it is set at a sensible & reasonable limit. Increasing the boost will put more load on your engine, and you must consider other tune-related factors. If in any doubt, speak with a professional tuner/calibrator.

What's a vacuum actuator?
n basic terms, traditional pneumatic actuators for wastegate control are boost-based, meaning they use a positive pressure to overcome a built-in/pre-fitted mechanical spring which then 'actuates' and opens a wastegate flap on the turbocharger so that exhaust gas can bypass the turbo & boost can be modulated. As the turbocharger creates more boost, the actuator has more potential force to overcome the spring pressure & open the wastegate flap. With Vacuum-Based Actuators, however, the reference signal is a vacuum (negative pressure) instead of a boost (positive pressure). This vacuum is generally sourced from a vacuum pump fitted to the engine (Either mechanically driven or electronic). The vacuum, unlike boost-based systems, is consistent and does not change based on the boost pressure, RPM or power the engine is producing. Due to this boost control strategy is very different from a boost-based system.

Why would I upgrade my vacuum actuator?
The simple answer is leverage. We have created bolt-on upgrades for various vehicles fitted with vacuum actuators from the factory. When tuned, the forces can be greater, and higher boost levels can be harder to achieve. The additional boost cannot hold the boost like a boost-based system, and the tuning window is limited. By utilizing the improved working area & revised springs selection of a Turbosmart Vacuum vIWG you can expect to increase boost pressures to new, higher levels than your factory actuator.

Why would I retrofit a vacuum Actuator to my boost-based setup?
There are a few reasons you might consider this based on your turbocharger system. However, the most common we have come across is to assist with achieving cold-start emissions requirements. Traditional Boost-based pneumatic actuators require a boost (positive pressure) higher than the base spring pressure to open. While this generally does not cause any issues, it may do if your goal is to open the wastegate flap for cold starts. Often manufacturers use this strategy of opening the wastegate flap on cold starts at idle to increase the warm-up rate of the emissions devices such as catalytic converters. Cold-start conditions are often the hardest part of gaining emissions compliance for upgraded and modified cars, and a retro-fitted vacuum vIWG from Turbosmart can help.

What do I need to do to control it?
You will need an ECU and solenoid to manipulate the actuator successfully. The boost control strategy will be different from that of a boost-based system. If your vehicle was already fitted and calibrated for a vacuum IWG, returning and calibration will likely be required. As with all boost control changes, air-fuel ratio, torque and power must be checked.

What is twin port control?
The Turbosmart vIWG Vacuum Actuator series has been engineered with a second chamber on the other side of the diaphragm which means you can boost assist. This will require a more advanced strategy and setup however plumbing positive pressure from the inlet manifold or turbocharger directly or via a solenoid will allow a custom, much wider tuning window. What size is the reference fitting? The swivel banjo and fitting in the top cap is a -3AN, and the lower (optional) positive Pressure Assistance Port for Boost-Assist is 1/16NPT.