Details
IPD 81482-GT4 82mm Competition Plenum for 981 Cayman GT4 + Throttle Body

GT4 IPD Plenum delivers GT3 performance
Delivers gains throughout both power and torque curves
Smoother, more efficient air flow
Comes with 74mm OEM throttle body.
Porsche has once again left the door open for some additional engine performance improvements with the new GT4 by continuing to utilize the same factory intake found on the 981 S and GTS models. These intake systems employ the smaller more restrictive 74mm throttle body which limits power and torque potential. The new GT4 may have the 991 Carrera S 3.8L engine but it did not come with the larger 82mm TB that is OE for both Carrera engines. Again, Porsche is famous for controlling engine output by choking the inlet tract with a less than optimum TB size. This has handicapped the Cayman from treading on Carrera territory and the now it shackles the GT4 from entering the ring with the GT3.

Porsche claims the 991 Carrera S delivers 420 HP and the GT4 delivers 385 HP but if they are the same engine why does the GT4 produce a whopping 35 less HP? This means the GT4 engine is only 15 HP stronger than the 991 Carrera Non-S 3.4L engine. Of course these are only advertised figures and as we all know, "tuning" plays a crucial role in engine output. The bottom line is that Carrera S engine benefits from the IPD Plenum without a larger TB, so the GT4 should perform even better with the Plenum and more appropriately sized 82mm TB.

Comes with 74mm Porsche Throttle Body. This is the larger, German throttle body required to fit the larger 74mm "Competition" Plenum.