Does the Fabspeed GT3 Muffler Conversion Kit fit both the GT4 and the Boxster Spyder?

Yes. The GT3 Muffler Conversion Kit fits both the 981 Porsche Cayman GT4 and the 981 Boxster Spyder from 2015 to 2016, with the 3.8-liter flat-six. It is designed for six-speed manual cars only, so it is not compatible with PDK models. The kit lets either car run the free-flowing OEM 991 GT3 center muffler.

Is the OEM GT3 center muffler included in the kit?

No. The kit supplies the 2.5-inch over-axle pipes, the valved Y-pipes, and the mounting bracket needed to fit the OEM 991 GT3 center muffler, but the GT3 muffler itself is not included. You will need to source the OEM Porsche 991 GT3 center muffler separately to complete the conversion.

Will this work on a PDK car?

No. This conversion is built for six-speed manual GT4 and Spyder cars only and is not compatible with PDK-equipped vehicles. The over-axle pipe routing and valved Y-pipes are designed around the manual drivetrain, so PDK owners should not purchase this kit.

Does it keep the Porsche Sport Exhaust valve working?

Yes. The valved Y-pipes retain full Porsche Sport Exhaust (PSE) function, so the factory valve control still works exactly as it did from the factory. With the valve closed the car stays civil for daily driving, and with PSE open it delivers a louder, more aggressive note.

How much louder and faster is it?

The OEM 991 GT3 center muffler flows better than the factory GT4 and Spyder muffler, so the conversion adds a clear volume increase and a stronger top-end note, especially with PSE open to redline. Fabspeed notes a horsepower gain from the freer-flowing muffler; exact figures vary with the car and conditions.

Is the kit street legal and CARB compliant?

No. This kit is not CARB approved and is not legal for sale or use on pollution-controlled vehicles in California or other states that require CARB compliance. Check the regulations where you live before purchasing, as it is intended for use only where these exhaust modifications are permitted.

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Description

Fabspeed Valvetronic GT3 Muffler Conversion Kit for 981 Porsche Boxster Spyder & Cayman GT4

Porsche Boxster and Cayman owners have long requested a conversion kit that allows the installation of an OEM 991 GT3-style center muffler onto their vehicles. Fabspeed Motorsport responded by designing a lightweight installation kit, built in-house, that enables any 6-speed Porsche 981 GT4 or Spyder owner to install an OEM GT3 center muffler. This kit also supports the installation of the Fabspeed 991 GT3 Center Muffler Bypass Pipe or GT3 Center Mini Maxflo Performance Exhaust. Additionally, Fabspeed offers its own GT3 universal high-performance muffler, which is stronger and delivers more power than the OEM Porsche GT3 center muffler. The system includes 2.5″ CNC mandrel-bent, one-piece left and right over-axle pipes, along with clamps. The kit also features valved side muffler inlet Y-pipes that retain the factory PSE exhaust functionality, using OEM Porsche GT3 HELICAL aerospace-quality valves imported from Helical Great Britain. The lightweight, stainless steel mounting bracket is cut with Fabspeed’s FLOW Waterjet technology and is designed to securely hold the muffler, with hardware for installation included. Factory Porsche muffler band straps help keep everything in place.

Sound

The Fabspeed exhaust system enhances the characteristic sound of a factory Porsche exhaust with a noticeable increase in volume. With PSE off (valves closed), the exhaust remains tame and comfortable within the cabin. However, with PSE on (valves open), the flat-six engine delivers a thrilling howl all the way to redline. The larger over-axle pipes included in the system also contribute to a more pronounced tone.

Power

The 991 GT3 muffler, designed by Porsche to support 47hp, flows much better than the 981 GT4 muffler, which was only designed for 385hp. The increased flow, aided by Fabspeed’s larger over-axle pipes and muffler inlets, is expected to result in a noticeable horsepower increase.

Features

CNC Mandrel bent 2.5″ precision over axle pipes
Helical Aerospace United Kingdom exhaust valves
Valves contracted with 321 stainless steel and silica carbide
Constructed from 14-16ga T304L stainless steel tubing
Direct bolt-on installation; no cutting or welding required
Premium Fabspeed exhaust tips or use OEM 991 GT3 tips
All Fabspeed performance products are backed by the Fabspeed lifetime warranty

Applications

Porsche Boxster Spyder: 981 | 2015-2016 | 3.8L F6
Porsche Cayman GT4: 981 | 2015-2016 | 3.8L F6

Notes

All Fabspeed products are expected to ship within one week of order, though timelines are often much quicker
Owners can use factory 2007 997 to 2019 991 GT3 tips or opt for Fabspeed’s GT3 exhaust tips
Not designed for vehicles equipped with PDK transmissions
OEM GT3 center muffler is not included

Frequently Asked Questions

Does the Fabspeed GT3 Muffler Conversion Kit fit both the GT4 and the Boxster Spyder? Yes. The GT3 Muffler Conversion Kit fits both the 981 Porsche Cayman GT4 and the 981 Boxster Spyder from 2015 to 2016, with the 3.8-liter flat-six. It is designed for six-speed manual cars only, so it is not compatible with PDK models. The kit lets either car run the free-flowing OEM 991 GT3 center muffler.
Is the OEM GT3 center muffler included in the kit? No. The kit supplies the 2.5-inch over-axle pipes, the valved Y-pipes, and the mounting bracket needed to fit the OEM 991 GT3 center muffler, but the GT3 muffler itself is not included. You will need to source the OEM Porsche 991 GT3 center muffler separately to complete the conversion.
Will this work on a PDK car? No. This conversion is built for six-speed manual GT4 and Spyder cars only and is not compatible with PDK-equipped vehicles. The over-axle pipe routing and valved Y-pipes are designed around the manual drivetrain, so PDK owners should not purchase this kit.
Does it keep the Porsche Sport Exhaust valve working? Yes. The valved Y-pipes retain full Porsche Sport Exhaust (PSE) function, so the factory valve control still works exactly as it did from the factory. With the valve closed the car stays civil for daily driving, and with PSE open it delivers a louder, more aggressive note.
How much louder and faster is it? The OEM 991 GT3 center muffler flows better than the factory GT4 and Spyder muffler, so the conversion adds a clear volume increase and a stronger top-end note, especially with PSE open to redline. Fabspeed notes a horsepower gain from the freer-flowing muffler; exact figures vary with the car and conditions.
Is the kit street legal and CARB compliant? No. This kit is not CARB approved and is not legal for sale or use on pollution-controlled vehicles in California or other states that require CARB compliance. Check the regulations where you live before purchasing, as it is intended for use only where these exhaust modifications are permitted.

About Fabspeed

Fabspeed Motorsport is situated in Fort Washington, Pennsylvania, within the United States of America. Their extensive 26,000 sqft. facility serves as a hub for various car clubs, including Porsche Club of America, Ferrari, McLaren, Lamborghini, and more. The company is renowned for its comprehensive approach to product development. They handle the entire process, from design and engineering to dyno testing, street trials, and racing assessments, ensuring the quality and performance of every item. Fabspeed also collaborates closely with race engine builders and tuners hailing from Italy, Germany, and the United States, resulting in the creation of the Ultimate Performance parts. To cater to their passionate global audience, Fabspeed meticulously crafts systems using aerospace-grade austenitic stainless steel, titanium, and carbon fiber materials, setting a standard for excellence in the industry.

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.

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Fabspeed Valvetronic GT3 Muffler Conversion Kit for 981 Porsche Boxster Spyder & Cayman GT4 [FS.POR.981GT4.GT3CKXR]

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Fabspeed Valvetronic GT3 Muffler Conversion Kit for 981 Porsche Boxster Spyder & Cayman GT4

Sound

Power

Features

Applications

Notes

Frequently Asked Questions

About Fabspeed

Reviews