It's not actually empty, it's full of ducting for the turbo charger, (which is also very large), and intercooler which sits in the aft section of the fuse. The backwards facing scoop on the bottom of the fuse is the exhaust for the turbo. The wastegate exhausts right behind the oil cooler flaps on the lower forward section of the fuse. The doors in the middle of the fuse are for the intercooler.
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