Porsche 991 GT3 & GT3 RS Air Filter Installation and Bumper Removal Guide
Porsche 991 GT3 & RS Air Filter Install & Bumper Removal
Accessing the engine air filters on the 991 chassis requires removing the rear bumper cover. While this sounds aggressive, it is a straightforward bolt-on, bolt-off procedure that saves you a significant amount on labor costs.
The Short Answer (TL;DR)
To change the air filters on a 991 GT3 or RS, you must remove the rear bumper. Total time is 45-75 minutes. Tools required are T20, T25, and T30 Torx drivers. Remove the rear wheels for access, undo the screws in the wheel arches, under the bumper, and under the engine lid. Disconnect the tail lights to access a hidden screw, unplug the license plate harness, and pull the bumper. Swap the restrictive paper filters (GT3) for BMC high-flow units, or clean the factory BMCs (GT3 RS).
The DIY Process Overview
This job requires precision but no special diagnostic tools. You will need T20, T25, and T30 Torx drivers. Removing the rear wheels is highly recommended; while possible to do with wheels on, the limited clearance in the wheel wells makes it frustrating and time-consuming.
1. Wheel Well & Bottom Hardware
With the rear of the car jacked up and wheels removed, locate the five Torx screws inside each wheel well. Four are visible; the fifth is hidden behind the liner. Remove the top two with a T25 driver and the remaining three with a T30. Next, move to the underside of the bumper and remove the six T30 screws (two on each side, two near the exhaust outlet).
2. Top Hardware & Brake Lights
Open the engine cover. Remove the four black T30 screws running across the top of the bumper cover. Locate the two silver T25 screws above each brake light. These are long fasteners. Once removed, carefully slide the brake light assemblies out and disconnect the wiring harnesses. Set them aside safely.
3. The Hidden Screw & Bumper Removal
Removing the tail lights reveals a hidden T30 screw on each side. Remove these. Now, pull the bumper rearward slightly to expose the license plate lamp connector on the left rear side. Disconnect this plug. With a helper (preferred) or careful hand positioning, pull the bumper straight back to release it from the chassis.
4. Airbox Access
The air filter housing is now exposed. Remove the T20 screws securing the housing halves (note: factory manual may say T30, but T20 is standard here). Hinge the housing backward and pull up to remove it. You can now access the filter elements.
Why You Should Upgrade While You're In There
If you have a standard GT3, your car came from the factory with paper filters. These are designed for cost and maximum filtration at the expense of flow. The GT3 RS comes stock with BMC high-flow filters for a reason: the engine needs to breathe. Since you have the bumper off, this is the only time to perform this upgrade without repeating the labor.
Furthermore, with the bumper removed, the exhaust system is fully accessible. This is the ideal window to install a center bypass or side muffler deletes to reduce weight and manage heat.
Recommended Fix: BMC High Performance Air Filters
Shop Porsche 991 GT3 Upgrades Here
Frequently Asked Questions
Do I really need to remove the rear wheels?
Technically, no. However, accessing the screws inside the wheel liner requires contorting your arm into a tight space. You will work blindly and risk stripping the Torx heads. Removing the wheels cuts the frustration significantly.
What is the difference between GT3 and GT3 RS filters?
The GT3 RS is equipped with washable cotton-gauze BMC filters from the factory. If you own an RS, inspect and clean them. The standard GT3 uses disposable paper filters. Upgrading the GT3 to BMC filters improves throttle response and intake sound.
