DEVELOPMENT: 718 GT4/Spyder Exhaust Suite Part 2

Over the past few weeks we’ve come a long way on development of our 718 GT4 exhaust suite!

Competition Over Axle Pipes

Below are a couple photos of our prototype set used in the video we posted. The thick gauge aluminum fixture has been finalized to prepare for production. The bend profiles are currently being 3D scanned to have the primary flow path piping bent into the profile, eliminating five welds on the driver side and four welds on the passenger side. At that point we will test fit the final production version, take professional photographs of the finished product, compare the weights between ours and factory, and release this as the first product available for the 718 GT4 platform in July.

Below is a photo of Porsche’s part numbers for these over axle pipes. Note there are three versions of these over axle pipes – not two – and all three use particulate filters. We know North American versions are all the same and unmonitored, while Europe has the monitored versions. We’re waiting on clarification on what the mystery third set is for the region and if there is any change in the design. The North American version from Porsche retails for $3288 per side, by the way. Huge shoutout to our friends at for working with us on doing a deep dive on this!

Competition Headers

It is very tight on space with the underbody panel on this car and these constraints have made header development a challenge. We’re focusing our initial efforts on a set of competition headers as we don’t have to worry about incorporating a cat core. Below are photos of the prototype headers we have built and test fit. It is especially tight to the engine and underbody panel on the driver-side (left) and requires some additional revision to clear which we are working on as we speak. The first version of these headers – for those that are antsy to get a set – will have laser cut header flanges to the spec of our prototype. However, we are taking these header flanges a step further and have designed and 3D printed the flanges for these headers to be sent out and cast or CNC machined to eliminate three welds per side. These will take several months to receive back and will from that point be incorporated into the headers. Regardless of which set you receive, the laser cut vs cast flanges will have a negligible effect on performance and they will both come with our Lifetime Warranty for both street and track use. Realistically, the Competition Headers could be available in July.

Race Exhaust

As you may have seen in the PSE muffler explanation video in our last post, the factory PSE system is very well designed from a mild to wild standpoint. We still firmly believe that uncorking the exhaust system upstream from that PSE muffler is going to provide an ample improvement in terms of sound and performance to meet the goals of the vast majority of 718 GT4/Spyder/GTS owners. The race headers, street headers, and competition over axles pipes (GPF deletes) are in the final stages of R&D and will be released soon – are you on our waiting list?

That said, some of you may ask… what about the track rats? What about those of us that live in the high rpms and want to hear this car working and maximize the driver’s connection? Those that are in the minority, that don’t value cruising speed comfort as much as weight loss and maximizing flow/sound characteristics. We thought about you too, and this is what we’ve come up with for our Race Exhaust, which can bolt right up to the factory headers or our race/street headers.

The factory dual exit/entry flanges connecting the over axle pipes to the PSE muffler limit the piping diameter to 2.25″ – we’ve eliminated those. Our system is full 2.5″ all the way as we’ve eliminated the factory over axle pipe to PSE muffler connection. We’re using an X-Pipe to accommodate resonated and non-resonated options. The longer piping routing also helps noticeably smooth out the exhaust sound while the slight blending of the X gives the car a higher pitched sound more akin to the previous 981 generation we’ve come to know and love. The resonated version sheds 29lbs while the non-resonated variant drops 32.3lbs. The bend profiles are being 3D scanned and our mandrel-bent versions will eliminate a dozen welds from the design. Like all of our products, it is fabricated from T304L stainless steel and back purged with argon gas for maximum longevity under sustained high rpm abuse, and is backed with our Lifetime Warranty for street and track use.

Valved Rear Exhaust System

The PSE muffler is very well designed, check out the explanation video below of how. If you want an exceptional valved exhaust system while at the same time uncorking the main performance restrictions on the car, you should strongly consider simply freeing up the flow upstream of the PSE muffler with our competition over axles pipes and perhaps a combination of our headers. If headers and over axles pipes are not something you can do due to stringent emissions restrictions, we are working on a valved rear exhaust solution.

We have gone through four versions of different valved rear exhausts on this car and about twenty different iterations of them. This car needs a muffler to kill the drone with valves closed, the drone range is too wide (about 1,000rpm) to eliminate completely with traditional resonators and/or a combination of Helmholtz resonators. That brings it’s own challenge, the rear diffuser takes up a remarkable amount of space back there to put a muffler. Unfortunately none of the existing dual entry/dual exit mufflers available on the market were suitably designed in shape, size, internals and quality to meet the goals we have for sound/drone requirements, flow characteristics, spacial restrictions and longevity on this car. Therefore, we designed our own bespoke muffler for the GT4/Spyder/GTS!

The first step was to 3D print a muffler shell to accommodate the spacial requirements on the car. Once this was done, we utilized a chambered x-pipe internal design based off of an extraordinary successful venture designing a one off valved exhaust system for Larry of AMMO NYC’s Audi R8. The video of that project is below and its a great watch if you want to check out the whole thing. However, you’ll see the muffler design in detail from 3:00-4:30. I’ve also included some photos below of our rendition of this muffler specifically for the GT4/Spyder/GTS. Due to the complexity of this design and how labor intensive they are, we are having our mufflers made to our exact specifications in a large number by one of the fabrication facilities we partner with. This way we will have them readily available on the shelf to reduce the lead time of getting them in your hands dramatically.

Don’t want to watch the whole video? Skip to 3:00-4:30 for our muffler design

Stay tuned for our next post!

Contact us at for early adopter info and details

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Questions? Comments? Let us know!

– Mike Spock / Marketing Manager