Mazda’s Skyactiv-D racing program has struggled running its first two races in the new Grand Am GX class. It has 2 Turbos in line. First it goes thru 1 Turbo, then another: the low-pressure side is a Garrett GTR3776R turbo while the high-pressure side sports a GTR2560R unit. Exact numbers weren’t disclosed, but the class is designed for engines producing around 400 horsepower. Mazda says the Skyactiv-D pulls over 445 lb-ft of torque at 3,600 rpm. Max boost is reported to be 70 psi. Other specs that have been released include 2.2-liter with a 86mm bore and 94.3mm stroke, and the common-rail direct-injection system is controlled with a Bosch ECU. Mazda says more than 250 part numbers from the production engine are used in the race version. The engine must also carry over the stock 14:1 compression ratio.
It sure looks pretty. to see Video of it on DYNO which shows both turbos running.