Lada sequential turbo system with Triflux cylinder head.

Описание: Sequential turbo system for Lada(VAZ) classic engine family for 2101 to 2107. The system uses two turbochargers, working in sequence. First works the passenger side turbo. Before the driver side turbo, there is a butterfly valve that at is initially closed and all of the exhaust gases are directed to the passenger side turbo. After the passenger side turbo build boost and there are enough exhaust gasses, the butterfly valve opens and both turbochargers work together. This is very simplified explanation, but hope it is clear enough.
This setup is possible by using a special 16 valve cylinder head, where the valves of each type are not side by side, but in diagonal relation. This means that you have exhaust and next to it it is intake valve and across the cylinder is the other way around. This gives the arrangement of exhaust manifold on each side of the cylinder head and an intake in the top middle of the head.This is developed by Lancia for their ECV1 prototype for Group B.
The air charge is cooled by water to air intercoolers, one for each turbo.

You can see more here:
vftsmotorsport.com/portfolio/
(Copy and paste the link in your browser of choice)

All the best.