xedos 9's?

2.3 was the "special" Miller cycle engine, used smaller capacity engine but came up with similar performance, you know Mazda, loved to play with different engines around ten years ago!

"A traditional Otto cycle engine uses four "strokes", of which two can be considered "high power" – the compression stroke (high power consumption) and power stroke (high power production). Much of the internal power loss of an engine is due to the energy needed to compress the charge during the compression stroke, so systems that reduce this power consumption can lead to greater efficiency.

In the Miller cycle, the intake valve is left open longer than it would be in an Otto cycle engine. In effect, the compression stroke is two discrete cycles: the initial portion when the intake valve is open and final portion when the intake valve is closed. This two-stage intake stroke creates the so called "fifth" cycle that the Miller cycle introduces. As the piston initially moves upwards in what is traditionally the compression stroke, the charge is partially expelled back out the still-open intake valve. Typically this loss of charge air would result in a loss of power. However, in the Miller cycle, this is compensated for by the use of a supercharger. The supercharger typically will need to be of the positive displacement (Roots or Screw type) type due to its ability to produce boost at relatively low engine speeds. Otherwise, low-rpm torque will suffer."

Miller cycle - Wikipedia, the free encyclopedia

Just to add to Steve's post...

The 2.3 L (80.30 mm bore 74.20 mm stroke, 2255 cc) KJ-ZEM is one of Mazda's most technologically advanced engines. It employs the "Miller cycle" which uses a supercharger to decrease compression losses and increase power. It was used in the T-platform cars. The supercharger used is the twin-screw type with electronic boost control. Power output was 217 hp (162 kW) and 210 ft·lbf (280 N·m). The KJ-ZEM was on the Ward's 10 Best Engines list for 1995 through 1998.

Basically, it is said that this engine has the power of a 3.0l V6, but with the economy of a 2.0l engine.. you will see from the figures, it is even more powerful than the KL-ZE.. (199 hp (149 kW) and 165 ft·lbf (224 Nm).)

My thoughts were at one time to see if this could be fitted to a 6.. although bear in mind that this engine was only ever mated to an auto transmission.. so the ECU may have to be "fettled"

The 2.5 KL from what I have read, is the KL-ZE... but I wouldn't take that as gospel for the UK market..
Looking on autotrader, they vary from £975 - £2395


John