IPD Competition Plenum for Porsche 981 Spyder/GT4

Once again, Porsche left the door open for engine performance improvements with the 981 Boxster Spyder and Cayman GT4. Using the same factory intake found on the less-powerful 981 S and GTS models, despite using the 911 Carrera S 3.8L engine, the intake's 74mm throttle body limits power and torque to keep the 981 from treading too close to the 911. As a result, Porsche's 991 Carrera S delivers 420 HP while the GT4 makes 385 HP with the same engine.

Why does the GT4 produce 35 fewer horses? (The GT4 engine is only 15 HP stronger than the base Carrera 3.4L engine!) The Carrera S engine, with its 82mm throttle body, benefits from the IPD Plenum, so it figures the GT4 would really benefit from an IPD Competition Plenum and 82mm throttle body.

Initial dyno tests performed in Germany showed gains of 18 HP and 17 lbs-ft. of torque at the GT4's wheels. Considering that the 981's ECU requires more adaptation time than other Porsche models (over a hundred miles for the full adaptive process), this means the full performance gains for the GT4 will be even greater.

Thunderhill installed the IPD Competition Plenum and 82mm TB on our GT4 and were immediately impressed with the increased mid-range and top-end power and torque, and throttle response. The IPD plenum delivers net gains throughout both power and torque curves, helping the GT4 compete with its GT3 big brother.

This plenum requires a Bosch 82mm throttle body, which can be added to your order above for only $225 (save $100).