Fabspeed Side Muffler Bypass Pipes for 997.2 Porsche 911 GT3 & GT3 RS
Fabspeed’s Side Muffler Bypass Pipes for the 997.2 Porsche 911 GT3 and GT3 RS give a Mezger-engined 911 the voice its chassis has always deserved: the heavy, restrictive factory side mufflers come out, and a straight-through stainless path goes in. Fabspeed designs, fabricates and dyno-tests its own exhaust work in Fort Washington, Pennsylvania, and that discipline shows here; 34 pounds leave the rear of the car, throttle response sharpens, and the note hardens into the CUP car sound owners chase, without the resonance and drone that ruin a road drive. Valved and Non-Valved configurations let an owner decide how much of that voice is on call. For the GT3 owner who tracks the car on Sunday and drives it home on the same set of tires, this is the most honest hardware change on the shelf.
Construction
Each pipe is fabricated from 14-16ga T304 stainless steel, the aerospace-grade austenitic alloy Fabspeed uses across its exhaust range, chosen because it shrugs off the heat cycling and winter salt that pit thinner, cheaper stainless. The heavier wall is deliberate: gauge is what stops a bypass pipe ringing once the mufflers that used to damp it are gone. Welds, flanges and hanger positions mirror the factory locations, so the Side Muffler Bypass Pipes drop into the stock mounting points with no cutting, no welding and no fabrication on the car.
Helical Valves
The Valved configuration runs Helical pneumatic butterfly valves, the same units supplied to McLaren, Ferrari, Lamborghini, Aston Martin and Pagani for their own production cars. They open and close with precision to regulate gas flow and optimise engine back-pressure, and Helical’s high-volume OEM experience shows in the details: a durable pneumatic actuator, precision flat sealing faces inside the valve body, stiffening ribs, and high-temperature bearings at both ends of the butterfly spindle. Fabspeed specified them over the low-cost imported valves common in this category because a valve that sticks or leaks on a track day is worse than no valve at all.
Features
Replaces the factory side mufflers with a straight-through path for improved exhaust flow
Replicates aggressive CUP car sound for the street, with no resonance and no drone
Helical pneumatic exhaust valves on the Valved configuration, proven in OEM supercar applications
Lightweight, with the mass removed from behind the rear axle
Level-1 install difficulty; bolt-on to factory mounting points with no cutting or welding
The Side Muffler Bypass Pipes replace the factory side mufflers only; the rest of the factory exhaust system stays in place
Power and torque figures are taken from a specific vehicle at ambient conditions. Results vary with the car, its state of tune and the conditions on the day.
Fabspeed products are expected to ship within one week of order, though timelines are often much quicker
Frequently Asked Questions
What is the difference between Side Muffler Bypass Pipes and a center muffler bypass on a 997.2 GT3? Side Muffler Bypass Pipes replace the two side mufflers and leave the centre muffler in place, which yields a smoother, more exotic version of the factory note and keeps highway drone in check. A centre muffler bypass works the other end of the system for a rawer, deeper tone and a sharper step when the valves open. Many owners fit one, live with it, then add the other.
Do these pipes drone on the highway? No. Fabspeed builds them to replicate a CUP car note without resonance or drone, and routing gases through the retained factory centre muffler keeps cruising volume civil. The Valved configuration adds a second layer of control: closed, the car stays composed enough for a long road trip; open, it releases the full note on demand.
What is the difference between the Valved and Non-Valved configurations, and how are the valves operated? The Non-Valved pipes are a fixed straight-through path and sit at full volume all the time. The Valved pipes use Helical pneumatic butterfly valves that open and close to regulate gas flow and back-pressure. Fabspeed publishes an install guide for wiring those valves to the car’s Homelink buttons, so the driver switches the note from the cabin.
What are the Fabspeed Side Muffler Bypass Pipes made from? They are fabricated from 14-16ga T304 stainless steel, the aerospace-grade austenitic alloy Fabspeed uses across its exhaust range. T304 resists the heat cycling and road salt that pit lesser stainless, and the heavier gauge keeps the pipes from ringing once the factory mufflers are gone. The Valved configuration adds Helical valves, the same pneumatic units supplied to several supercar manufacturers.
Do these require an ECU tune? No. Fabspeed lists these as a bolt-on change at Level-1 install difficulty, and no software is required to run them. Owners chasing the full return from a headers-and-exhaust build often add Fabspeed XperTune Performance Software, which is calibrated for the 997.2 GT3 and GT3 RS, but the pipes stand on their own.
Which Porsche models and years do these fit? They fit the 2010-2011 Porsche 911 GT3 and 911 GT3 RS built on the 997.2 chassis with the 3.8L flat-six. Fabspeed builds separate systems for the earlier 997.1 GT3 and for the 991 cars, so check the chassis code on the car before ordering rather than the model name alone.
About Fabspeed
Fabspeed Motorsport builds its exhaust, intake and software products in a 26,000 square foot facility in Fort Washington, Pennsylvania, a shop that regularly hosts Porsche Club of America, Ferrari, McLaren and Lamborghini club events. Every system is developed in house, from design and engineering through dyno testing, street trials and racing. Fabspeed works alongside race engine builders and tuners in Italy, Germany and the United States, and fabricates its systems from aerospace-grade austenitic stainless steel, titanium and carbon fiber.
Additional Information
-+
The Bulletproof Automotive website contains many thousands of products purchased in multiple different currencies. All of the prices are entered manually and accurately at the time of entry. Due to the consistently fluctuating international exchange rates, at times prices may not be able to be honored at their original intended rate. We apologize for any inconvenience this may cause, unfortunately our website is unable to compensate dynamically for what can at times be volatile changes in the cost of items due to currency values fluctuating, changes in prices from suppliers, changes in shipping and import duties, and other factors. Rest assured that any order you place on line will be at zero risk to you in this area. If in the event your order cannot be fulfilled at the original intended website price we will offer you a 100% refund, no questions asked. We will continue to do our best to maintain updated prices and we will always continue to offer our price match guarantees as well to ensure our prices are always the best for you. In short, prices may change without notice. It is always advised to give us a call prior to placing your order online to confirm availability and to confirm current pricing.
Shipping Policy
-+
Items that are in stock in the US, either at Bulletproof’s warehouse or at a supplier’s warehouse, are generally delivered within 7-10 days. Special order items from overseas take considerably longer. As a courtesy Bulletproof offers delivery estimates to our customers which take into consideration manufacturer availability and shipping schedule. These estimates represent our best guess based on previous orders from the manufacturer and do not in any way imply a guaranteed delivery window. Many manufacturers work in a “just in time” inventory system and often take 2-20+ weeks to produce an item once an order is submitted. All deliverable items are then sent to our Japanese warehouse. Bulletproof ships a minimum of one full ocean freight container every month from Japan, oftentimes more than one a month. Ocean freight takes an average of 4 weeks. Typically it breaks down to one week in Japan for paperwork and customs, two weeks by boat and one week in US customs/clearance. Due to the wide number of variables between manufacturer and shipping schedules, delivery estimates are simply just that – estimates. We attempt to estimate conservatively and we usually deliver faster than our estimates suggest. It is not Bulletproof’s policy to guarantee delivery time of any special order item, this is impossible for us to do. By ordering you acknowledge that there is no required delivery ETA and an order may not be canceled or altered due to manufacturing or shipping delays, all ETA’s are provided as a best guess only. Please review the full Terms & Conditions here.
BP Pricing Difference
-+
We do pricing a little differently on our JDM brands and we believe in making things simple and clear. No hidden fees or surcharges. Every price you see includes the shipping cost to our office in Los Angeles, California and all the associated taxes/duties/fees for bringing the products into the US. The only shipping you ever pay is from our facility in the US to your location. Be wary of resellers that don’t include the cost of international shipping in their pricing on JDM parts. While we believe we’ll always have the lowest all-in price on JDM products, we offer a price match guarantee for all authentic parts purchased from authorized dealers as well.
For many international customers, it’s much more affordable to ship from the USA than from Japan directly, as the air freight and ocean freight costs are typically much less. However, for customers looking to ship directly from Japan outside of North America, or domestically in Japan, we can provide pricing specifically for that scenario. Please do not hesitate to contact us with any pricing questions or concerns. Please email us at sales@bulletproofautomotive.com with any inquiries.
Reviews
-+
Reviews
There are no reviews yet.
Only logged in customers who have purchased this product may leave a review.
Stay up to date with the latest product releases, Bulletproof Automotive builds and more. Sign up for our newsletter to receive the most up to date information in the aftermarket tuning world, and bring your build to a whole new level.
![Nitron NTR-R3 Coilover Kit w/ Standalone FAL for 997 Porsche 911 Carrera 4, Carrera 4 GTS, Carrera 4S, Turbo, and Turbo S [NTCPO026R3+FAL]](https://bulletproofautomotive.com/wp-content/uploads/2026/06/060926-500-1-450x450.jpg)
![SOUL Performance Race Pipes for Porsche 991.2 Carrera / S (without PSE) [POR.9912.CBP]](https://bulletproofautomotive.com/wp-content/uploads/2026/06/SOUL-Performance-Products-Porsche-991.2-Carrera-non-PSE-Cat-Bypass-1-450x450.jpeg)
Reviews
There are no reviews yet.