The Mazdaspeed DISI engine has proven to be a remarkably stout and tunable platform. That being said we have found that it has one major limitation, the factory "High Pressure Fuel Pump" .
Unlike a traditional fuel injected gasoline engine that runs a relatively low fuel pressures, roughly 30-40psi. Mazda's Direct-Injection requires very high fuel pressure upwards of 1,600psi. This is accomplished with a mechanical fuel pump driven by the valve-train.
This mechanical fuel pump is unfortunately undersized for the engine. When we make more power from these engines it is not uncommon for fuel pressure to drop and the engine to run lean.
If you own a Mazdaspeed and plan to run one of our higher performance maps such as any Stage 2 map or even a Stage 1+Inter-cooler map you will need to upgrade this pump, the exception being some Mazdaspeed6/Mazda 6 MPS/Mazda Atenza MPS vehicles which has a more capable pump from the factory. It is important to monitor your fuel pressure!
There are several aftermarket companies that offer upgraded HPFP internals or even entire replacement pumps.
For any specific questions, please contact technical support.