The design mission

The mission is to retain sea level power to a reasonable altitude, in the region of 18000ft.

All normally apirated piston engines loose power as altutude increases and air pressure decreases. At sea level, approximately 29.92 inches of manifold pressure is available to produce 100% of the rated power. With each 100ft of altutde, app 1" of pressure is lost. So it can be seen that at roughly 15,000 ft only half of the sea level power is available.

This is nothing new, but getting an elegant and simple solution is a challenge. Some 30 years ago this challenge was met by the Rajay Company who produced a kit for the Piper PA30 Twin Commanche series.

In my solution, I have adapted the Rayjay method with some differences.  The Rajay setup used no wastegate of pressure releif device - the only protection against overboost was the pilots manual control and observation of the manifold pressure gauge.

This is not acceptable when there are modern solutions which can give protection.

Another advance of the Rajay design, not available in the late 70's, is electronic engine management.
Our installation integrates an electronic engine management system from SDS (Simple Digital Systems)

Bosch fuel injectors are installed in custom made intake pipes which some together behind the sump, keeping the installation compact, allowing the best possible streamlining of the cowlings, and hence the best possible inflow to the propeller. These also allow mounting of the injectors well away from the radiant heat of the exhaust pipes.

To do this, a custom sump was fabricated, since the standard sumps integral intake tubes were not needed.

Another requirement of a turbocharged engine is that it be operated at higher altitudes where efficiency is better. The higher altitudes are the colder altitudes with 2 degrees centigrade temperature drop per 1000 feet. Therefore a heater is not an option - it is an essential piece of equipment.
The Piper PA30 series had Janitrol or Southwind gasoline burning heaters, which are not an option in a small lightweight pusher. Hot air is not a practical one either, since a) it looses heat and efficiency getting from the rear of the aircraft to the front   b) there is already a surfeit of plumbing in the engine bay with the turbo installation.
This we designed the aluminium sump with an integral heat exchanger . This will be used in conjunction with a Bosch coolant pump to transfer heat to the nose where it will;
a) provide cabin heat  b) provide oil cooling (overboard venting)  c) move weight to the nose to counterbalance the turbo weight aft of the CofG.