Turbosmart Guide: Kompact EM Diverter Valves & IWG Actuators

Turbosmart Guide: Kompact EM Diverter Valves & IWG Actuators

When you increase the boost pressure on a modern turbocharged engine, the factory boost control hardware immediately becomes a liability. Factory diverter valves are mass-produced from plastic with weak rubber diaphragms, designed strictly for cost and quiet operation. Under high boost, they tear, leak, and struggle to respond, robbing your engine of horsepower and throttle response.

Founded in Australia in 1997, Turbosmart is a global pioneer in boost control engineering. From World Time Attack champions to aggressive street builds, Turbosmart’s billet aluminium hardware delivers absolute precision.

If your car feels sluggish between gear shifts or your boost pressure tapers off at high RPM, here is exactly how Turbosmart Diverter Valves and Internal Wastegate Actuators (IWG) fix the problem.

Ready to lock in your boost pressure? Check out our complete Turbosmart collection here!

Diverter Valves: The Kompact EM Series

When you lift off the throttle, your turbocharger is still spinning at over 100,000 RPM, forcing pressurised air into a closed throttle body. A diverter valve (or blow-off valve) gives this air an escape route, preventing destructive compressor surge (turbo flutter) that can shatter the turbine wheel.

Turbosmart’s flagship upgrade is the Kompact EM (Electro-Mechanical) Series. These valves combine the ultra fast electronic control of your factory ECU with the indestructible reliability of a billet mechanical piston. They are true plug and play upgrades, no messy aftermarket vacuum lines or adapters required.

Choosing Your Sound Profile: Dual Port vs. Plumb Back

Feature Kompact EM Plumb Back Kompact EM Dual Port
Venting Style 100% Recirculating 50% Recirculating / 50% Atmospheric
Acoustic Profile Silent / Factory-like Aggressive "Swoosh" / Blow-Off Sound
MAF Sensor Safe? Yes Yes (Air split prevents rich-running)
Target Application Stealth builds, OEM+ daily drivers Enthusiasts wanting turbo theatrics

Specialized EM Fitments

  • Kompact EM VAG V2: Designed specifically for Volkswagen and Audi platforms (such as the EA888 engine in the Golf R and S3). It replaces the notorious plastic factory 'Rev G' and 'Rev D' valves with a motorsport-grade billet unit that handles aggressive Stage 2 and Stage 3 remaps flawlessly.
  • Kompact EM VR1: A universal high-performance option for custom builds, featuring a high temperature solenoid and Boost-Balance technology.

The Boost-Balance Advantage

Standard diverter valves can be blown open by high boost pressure. Turbosmart's Boost-Balance design routes manifold pressure to the back of the internal piston. The more boost you run, the harder the system forces the valve shut, ensuring a positive O-ring seal and zero boost leaks.

Internal Wastegate Actuators (IWG): Holding Top-End Boost

The turbo actuator (wastegate actuator) is the gatekeeper of your turbo. It controls exactly how much exhaust gas drives the turbine and how much bypasses it.

The Problem - Factory actuators use weak internal springs. When you map your car for higher boost, the exhaust backpressure inside the manifold skyrockets. This immense pressure physically pushes the wastegate flap open against the weak factory spring, causing your boost pressure to drop off a cliff as you approach the redline.

The Turbosmart IWG Solution - Turbosmart’s Internal Wastegate Actuators are machined from billet aluminium and fitted with stainless steel rods. By upgrading to an IWG with a stiffer base spring, you force the wastegate flap to stay shut against high exhaust backpressure, ensuring your turbo holds peak boost all the way to the rev limiter.

  • Silicon Nomex Diaphragm: Unlike factory rubber that degrades and splits under extreme under-bonnet heat, Turbosmart uses a proprietary Nomex-reinforced diaphragm for rapid, heat-resistant actuation.
  • Locking Collar Design: Need to change your base spring pressure for a new turbo setup? The billet locking collar allows you to swap internal springs in minutes without needing specialized bench tools.
  • Twin Port Options: For aggressive track builds utilizing electronic boost controllers, twin-port IWG models allow pressure to be routed to both sides of the diaphragm, offering unparalleled, granular control over your boost curve.

If your turbocharged car is running more boost than stock, the factory plastic valves and weak wastegate springs are already costing you horsepower. Upgrading to Turbosmart’s billet electro-mechanical diverter valves and IWG actuators provides razor-sharp throttle response, eliminates boost leaks, and ensures your engine holds maximum power all the way to the redline.