Turbosmart Boost Tee Manual Boost Controller

The Boost Tee works as a pneumatic bleed valve, intercepting the boost reference signal sent to your wastegate actuator — internal or external — and allowing you to run boost levels well beyond what the base spring pressure alone would permit. Turbosmart's detent system makes adjustments defined and repeatable, so you're not guessing where you've landed between turns. The unique gate feature is what separates this from generic bleed valves: it maintains maximum boost response by preventing signal bleed at low pressure, keeping spool sharp and consistent.

For BMW owners running aftermarket turbos, hybrid setups, or bolt-on turbo kits on N54, S55, or older M-series platforms, the Boost Tee offers a straightforward path to more boost without the wiring complexity of an electronic controller. Gains of 100–200% over base spring pressure are commonly achieved depending on your setup and target. Once you've dialed in your boost level, the anti-tamper locking mechanism keeps it exactly where you set it — a practical feature for street builds where vibration and curious hands are both real concerns.

Installation is straightforward: the Boost Tee splices into the boost reference line between the turbo and wastegate actuator. No cutting into the ECU, no additional wiring, and no tuning required to get it working. It's the most cost-effective way to unlock more output from a turbo system that still has headroom, and Turbosmart's build quality ensures it won't be a weak point in your setup.