PCA Spotlight: We break, fix a Porsche 996 Carrera on way to more power with IPD intake plenum

It's not easy to increase the horsepower of a naturally aspirated engine, especially one that's power-optimized from the factory. Such is the case with the 996-generation Porsche 911 Carrera, which, short of spending several thousands of dollars, has no clear route to make meaningful power gains. Furthermore, there's not much independent testing available to quantify gains made from bolt-on modifications like throttle bodies, intake plenums, and exhaust systems. That's why we decided to find out for ourselves the results of swapping the stock intake plenum with IPD's plenum.
The 996 we used is a 1999 model with the 3.4-liter engine, which made 296 horsepower and 258 pound-feet of torque at the flywheel when new. Its sole powertrain upgrade before the plenum was a factory sport exhaust. Because we have no way of measuring horsepower at the flywheel, and keeping in mind the car has nearly 100,000 miles and has likely lost a few horsepower, we decided to bring the car to TPC Racing to measure horsepower at the wheels before and after installing the IPD plenum. The measuring tool of choice was an in-ground Dynojet.
In the video above, we perform baseline runs on the dyno before replacing the intake plenum, followed by more runs on the dyno to measure the increase in horsepower and torque. Watch to find out how much we gained with this simple $750 modification - and what we broke and fixed during the installation.
This video was sponsored by Pelican Parts, where you can purchase an IPD intake plenum: www.pelicanpar...