One manifold.
Two turbos.
A handoff you can feel.
The Hlava STM is true sequential turbocharging. Not compound, not parallel. Two different frame-size turbos, run in real sequence, with full flow control between them. Here is the sequence, step by step.
Small turbo spools first
At low load, exhaust feeds the small primary turbo for near-instant spool. As gas exits the primary, a three-inch bridgepipe channels it straight to the larger secondary turbo and primes it.
Bypass valves route the flow
As pressure and volume climb, dual inline full-flow bypass valves open incrementally ahead of the primary turbo, directing excess exhaust to the secondary. Spring tension in the actuators is adjustable.
Large turbo takes over
At full flow the valves move completely out of the gas path, sending maximum energy to the large turbo. It delivers the horsepower it was sized for, with low EMAP and intake air temps, while the small turbo stays primed.
What is actually in the casting.
The bypass valves self-regulate on the pressure, temperature, volume, and velocity of the exhaust gas. No sensors, no maps, no wiring required. You pick the secondary turbo for your horsepower goal and the primary for low-load response, and the manifold does the rest. That is what makes it universal across forced-induction builds.
Separate flow circuits
In a compound setup the small turbo feeds the large one to multiply pressure, and lag stays because of system inertia. In the STM the two turbos never feed each other. They run on separate circuits, so boost builds smooth and linear instead of stacking.
Wastegate optional
Simply add a traditional wastegate on your secondary turbocharger — but not as a constant exhaust gas control method in the traditional sense, instead to limit your peak boost level.