Marius,
Just a few things. The moment of inertia of this prop is within Jabiru spec, makes the engine more efficient. The EFI system is installed on a number of Jabirus only difference its done by the Factory and is throttle body injection ( therefore approved
)against direct port injection both systems do the same .
This engine is working no harder than any other engine just runs more efficiently.
A constant-speed propeller is a variable-pitch aircraft propeller that automatically changes its blade pitch in order to maintain a chosen rotational speed. The power delivered is proportional to the arithmetic product of rotational speed and torque (radians/second × torque), and the propeller operation places emphasis on torque. When an aircraft is stationary with the propeller spinning (in calm air), air flows past the narrow leading edge of the propeller. This is the most efficient configuration, as the drag forces on the propeller are the lowest. As the airplane starts moving forward, the airflow begins to push against the front, wider cross section of the propeller, creating greater drag.
A constant-speed propeller is able to partly rotate along the longest axis of the blade to take a larger bite of air with respect to the airplane, allowing the propeller to maintain the most efficient orientation to the airflow around it. This balances the tradeoff that fixed-pitch propellers must make between high takeoff performance and high cruise performance.
Here is some more reading......
In a constant speed prop airplane, you have both RPM and manifold pressure gauges. Generally, the MP gauge is the most direct method of measuring engine power output. The RPM gauge becomes a dedicate prop-related measurement giving you feedback on how fast the prop is rotating. Manifold pressure is just the air pressure of the air traveling through the intake manifold before it feeds to the pistons for the compression and combustion cycles. In non-turbocharged airplanes, manifold pressure cannot ever be more than outside air pressure (except for a half inch on takeoff) but can be reduced by "throttling back" on the throttle lever (which closes off the intake manifold butterfly valve). On takeoff, you can sometimes get a "ram air" effect from your forward velocity with the thick air at sea level, and sometimes exceed outside air pressure by no more than a half inch, but that is dependent upon your airplane. Usually the resistance given by the air filter on the manifold air intake will reduce the air pressure about an inch below outside air pressure even if the intake butterfly valve is fully opened (balls to the wall with the throttle).
A real world complex airplane's Pilot's Operating Handbook (POH) will always feature some form of power tables (or graphs) where you are given a matching set of MP and RPM settings which the engineers have determined correspond to a percentage of full power. Normally, there are three percentages considered useful for what is called "cruise power." Those three percentages are: 100%, 75%, and 65% of full horsepower. Also, often the terms, "Economy cruise," "Best cruise," and "Full Power cruise" are used in lieu of the outright percentage of full power values. If your airplane is not equipped with a turbocharger, then at around 6,000 feet, full power will be impossible to achieve because the air is too thin. As you increase the altitude, the max power value listed in the power table will further reduce until at around 12,000 feet you might only see the 65% power settings shown because it's the highest power you can achieve.
For a constant speed prop, you use the prop control lever to set a desired RPM and then the hydraulic prop governor uses the balancing forces of flyweights working against oil pressure on a piston in the governor to maintain that desired RPM setting. On a fixed pitch prop airplane, changes in aerodynamics (such as air pressure and airspeed) will often cause the RPM to rise of reduce without any change made in the throttle's power setting -- sometimes rather significant fluctuations in RPM that require you to throttle back to avoid exceeding RPM red line.
But, on a constant speed prop, within reason, electrical prop governor in this case makes subtle automatic adjustments in prop pitch to counter those changes in aerodynamic forces and therefore the RPM you set is tightly maintained even when you increase or decrease airspeeds or outside air pressures change. This is just one of the advantages to a constant speed prop airplane.
The other advantage of the constant speed prop airplane is perhaps the biggest one. It allows you to change the pitch angle of the prop blades to maintain optimal thrust. You see, as you increase forward airspeed, you have to flatten the angle of the prop blades to overcome what is called "relative angle of attack." You see, as the air flow in the direction of travel increases, the relative angle of the prop blades to the airflow changes since there is an increased horizontal velocity of the air. So, a fixed pitch prop can be carved (or molded) into three different blade angle shapes. These are called: speed props, climb props, or cruise props. The speed props produce max thrust at max airspeed. The climb props produce max thrust at slower speeds (normally Vy climb speed). The cruise prop produces max thrust at the normal cruising speed of the airplane.
But, the constant speed prop gives you the best of the three worlds! For takeoff and climbs, you set full RPM which rotates the blades to their finest angle relative the air flow. Since you takeoff and climb at Vy (which is much slower than cruise or max speeds) you need to rotate the blades to have the most fine angle. But, as you increase speed, you need to flatten out the blades, which is accomplished when you pull the prop control levers aft in the cockpit to reduce the RPM setting. By rotating the blades' angles to maintain this ideal relative angle of attack, you can reduce fuel consumption by letting the optimal blade angle allow you to throttle back the manifold pressure, which reduces fuel consumption but allowing you to maintain an airspeed that with a fixed pitch prop ideal for slower climb speeds would have required a higher level of fuel consumption to achieve.
In short, it is often true that with a given manifold pressure setting, a lower RPM will achieve a more ideal ratio of fuel consumption to speed, but not always. Again, you have to reference those power tables. The power table will give you a listing of altitudes you cruise at with various temperature ranges. If you want to cruise at 75% of power at say 3,000 feet, on a warm summer day, you consult the power table and look up the listings for 3,000 feet and then the column for standard day temperature plus ten degrees and then finally the entry for 75% power. As an example, it would likely show a manifold pressure setting of 24 inches mercury with an RPM of 2850-2900.
But, you always pay a price for anything you get in aviation. With constant speed props you have to pay attention and not put too much aerodynamic stress on the engine's crankshaft. You see, just as with a paddle on a canoe, when you flatten the blades of the prop, you increase the amount of air resistance on the blades. This causes more force on the blades and this force is translated directly onto the crankshaft which spins the prop. Therefore, you never fly with the manifold pressure full out with the RPM dialed way back. Yes, it can give you an outstanding fuel economy, but it can also cause physical destruction to your engine -- nasty little things like fractured crankshafts, exploded camshafts, or even thrown pistons through the engine cowling! These things will grab your undivided attention should they happen!
If you "modify" it....it's no more a Jabbi. I do not believe a Jabbi was designed for a three bladed CS prop. What would be the reason to fit it ?.....to get "better" performance from the same engine ?....without more stress ? and more heat created ? and a change in harmonics ?....I've been told the engine does not like any adjustable prop as they all are cylindrical(in order to be adjustable) at the engine air intake instead of flat to create engine cooling heat below flying speed (on the ground idling).Thanks for showing us your new project it is very interesting.....but a bit out of my financial capabilities. Lood is advertising a very beautiful V35 Bonanza (with a tried and tested 260 hp engine) at R800 000....just R300 000 more than a "modified " Rattex" 
:?I would much rather spend the time and energy on streamlining the airflow over/through the air frame.