We checked with Ford and, while they have not released many details of the engine, they did provide some explanation. The EcoBoost, like other recent DuraTec-badged Ford fours, shares a block design with Mazda's similar displacement units. In fact, the EcoBoost block is the same as the Mazda L3T used in the MazdaSpeed3. However, the entire top end of the engine has been redesigned. Like the V6 EcoBoost, the four uses a new direct injection system that is presumably less expensive and allows Ford to use these engines much more widely.
The Mazda engine also requires premium fuel. All of the EcoBoost engines are designed to run on regular, although they will get a bit more power with extra octane. The EcoBoost also gets independent variable timing for each of the intake and exhaust cams.
The upshot: the two engines are built on the same foundations, but they are not the same engine.
[Sources: Ford, Examiner.com]