In my few months’ experience, Mazda’s ECU is very sensitive to building boost rapidly, something my manual boost controller does all too well.

Summer time performance was acceptable and proved to be an overall net gain of horsepower, but once the snow flew I had nothing but misery as I turned the boost farther and farther down. To alleviate my suffering, I purchased a Cobb AccessPort to reprogram the ECU and viola my life was better.

I’m now running with the stock boost control system with the Cobb AP in charge and loving it.