metalone

Benjamin Clowes Fabrications Inconel Valved X Pipe Exhaust (718 Spyder)

Side note

If the Introduction below bores you, you might be better off skipping the rest of the review chapters. However, if you find it meaningful, it may be useful to you, whether you're just starting your search at the overwhelming big list of options available out there, or if you're looking for a second iteration of something you already have installed. It's true that there is a wide range of improvements and different qualities among exhaust solutions, but there will always be some compromise to make. For me, the key is to realize where the balance lies and have realistic expectations. This review aims to be as honest, neutral, and realistic as possible.



Chapter I: Introduction



Experience has taught me how difficult it is to achieve a good exhaust sound, and as a result, it has made me appreciate all the work that professionals in charge of this task had to do in OEM solutions, or rather, used to do, as is probably a dying specialty due to regulations and the imminent electric future ahead. Having moved on from a 981 Spyder, on which I also tried aftermarket exhausts, enjoying a muted 718 Spyder was inconceivable, knowing the beautiful sound potential of that 4.0 engine.



Whenever I read that an exhaust is perfect, supposedly without any weak points, like no drone at low RPMs and intoxicating sound at high RPMs, it generates an immediate disbelief and mistrust in me. There will always be exceptions, but I believe that the closest thing to reality are long iteration processes like the ones Obsessed Garage has shown on his channel with his own GT4.



This review is intended for people like myself who value honesty and thoroughness. But since each person has different auditory profiles and tastes, it is impossible to be completely objective, however I believe that describing a bit of my subjective auditory ‘tastes’ can be a helpful input to take into consideration.



I am one of those people who can hear the buzzing of certain devices connected in the room and have trouble sleeping because of it. I enjoy Hard Rock/Metal music, and as a hobby, I play the drums, so I appreciate loud sounds. I am a detail-oriented person, and this extends to sounds as well. Regarding drone, I can easily identify it, and while I don't love hearing it, I don't consider myself intolerant to it. In other words, I prefer having some drone rather than a completely silent car like the factory version of the 718 Spyder.



I took my beloved Spyder from the dealership on May 14, 2020, and 10 months later, I installed a marvelous Akrapovic titanium OPF (Original Particulate Filter) replacement combined with a Cargraphic X Pipe rear muffler (Racing). I was surprised by the increased power, ridiculously lightweight construction, and exquisite quality of the Akrapovic OPF. However, what truly blew me away was the high-pitched sound produced by the Cargraphic exhaust, especially above 4000 RPM. By October 5, 2022, I had replaced the Cargraphic exhaust with the wonderful Inconel X Pipe from BCFabs that I’m now reviewing with my Spyder showing 7000 miles of pure canyon weekends on backroads.



Chapter II: What was I looking for with the change? and What was the comparative result?

1. Lightweight:I wanted a lighter exhaust system with better finishes and made from superior materials.

Completely achieved. In my case, I opted for an Inconel exhaust, which is a nickel-steel alloy that allows for thinner tubing compared to stainless steel, making it significantly lighter. It offers the best possible rust tolerance and superior heat resistance compared to Titanium. The finishes are on another level compared to the Cargraphic exhaust, which, in fact, I had to repair due to a welding failure in one of the mounting brackets. As seen in the images, the exhaust weighs only 8.6 kg (18.96 pounds), and the welds are impeccable. It is the rear section that the Spyder deserved and from the quality to match the Akrapovic OPF.

1. No drone, sound always on: I wanted a better design because the Cargraphict’s quiet pipe path made the drone even more noticeable below 4000 RPM inside the cabin.

The result was more than outstanding; it showed me a world of new sounds below 4000 RPM and a completely unexpected increase in torque. BCFabs' design takes a completely different approach that goes beyond just the sound factor. Firstly, the quiet route doesn't have any mufflers; it is the high-flow route (from the X Pipe) that features a pair of straight silencers, which I understand are meant to slightly attenuate the sound without adding restrictions. What Benjamin Clowes has truly achieved is a variable geometry exhaust, allowing for higher-speed flow with the valves closed, thanks to the smaller pipe diameter being similar to the factory size but without the restriction of a muffler. This reduces backpressure through higher gas velocity during startup and generates an enjoyable, crisp sound without any drone.



Then, above 4000 RPM, when the valves open, the larger-diameter pipes come into play, combining the gasses in an optimized X Pipe configuration to reduce turbulence and maximize scavenging.



With the Cargraphic exhaust, I had a controller installed to keep the valves open, but it is now completely unnecessary, and I plan to uninstall it. Benjamin designed an exhaust that perfectly works with the factory valve logic. The resulting sound is never silent but always enjoyable with zero drone. It opened up a world of enjoyment below 4000 RPM that I didn't know existed. With the Cargraphic exhaust, I used to quickly pass through the 1000 to 4000 RPM range and drive trying to avoid it altogether. Now, that range is a constant joy with a strong and crisp sound. Be aware that if you're looking for a silent mode you won't achieve it; it's always sound-on but without any drone, the way I imagine Porsche would have done from the factory if EU regulations had allowed it.



Since it's currently cold in the Northern Hemisphere, I have gone out a couple of times with the convertible top closed. To my surprise, due to the sound having fewer bass tones and being more inductive, it's an equally if not more enjoyable experience than driving with the top down.

1. True X Pipe: I wanted to switch from a tangential X Pipe to a facing one to take advantage of the turbulence reduction benefits of this configuration.

Achieved. Under certain conditions, the previous tangential X Pipe produced vibrations, which were noticeably reduced with the current facing X Pipe. Although I don't have objective data for comparison on a dyno, I have the impression that there is a gain in horsepower compared to the tangential X Pipe.

1. High pitch: I wanted to maintain the high-pitched tone of the Cargraphic X Pipe above 5000 RPM.

It didn't meet my expectations. I believe that nothing can surpass the high-pitched note produced by the Cargraphic X Pipe (Racing type) above 5000 RPM. Despite the clear inferiority of Cargraphic in terms of finishes and materials, that exhaust manages to produce a delightful high-pitched wail. I think one of the key factors in the Cargraphic sound has to do with the merged pipe routing towards the path of the X Pipe when the valves are open, which should increase the gas velocity beyond what BCFabs achieves.



On the other hand, the sound of the BCFabs X Pipe reaches lower decibels, making it less brutal but more refined, delivering a clearer sound (more crisp without being raspy), which enhances the enjoyment of the Pops & Bangs. It is a very enjoyable sound, so it is by no means a disappointment, but it doesn't quite reach the "screaming" experience that the Cargraphic provided, which is a perfectly acceptable concession for me.

1. Level-up ready: I wanted to have the option in the future to move the catalytic converters to the OAP (Over Axle Pipe) to gain power without having to replace the rear section

This is a plus. Moving the catalytic converters away from the engine outlet is the ultimate legal upgrade to gain power that one could do, and this exhaust is prepared and designed to work harmoniously with this modification. The main limitation is the cost involved, especially with Inconel, which has seen a dramatic increase in costs. I believe that if I didn't have the Akrapovic Titanium OAP, I would have gone ahead with this modification already.



Chapter III: Summary



The switch to the BCFabs Inconel X Pipe exhaust has largely met the set expectations. The goal of obtaining a lighter exhaust with superior finishes and high-quality material was achieved. Additionally, the in-cabin drone below 4000 RPM was eliminated, allowing for an enjoyable and powerful sound experience throughout. The design of the true X Pipe successfully reduced turbulence and enhanced the auditory experience.



A notable aspect of the BCFabs X Pipe is its readiness for future modifications, such as the option to move the catalytic converters to the Over Axle Pipe (OAP) to gain additional power without replacing the rear section. This offers a higher-level option in terms of potential upgrades.



However, concerning the high-pitch tone above 5000 RPM, the BCFabs exhaust did not match the note produced by the Cargraphic X Pipe. Nonetheless, this concession is acceptable and does not significantly impact the overall experience. One thing worth noting though is that Benjamin Clowes took my feedback and made some internal changes of the silencers to achieve a higher pitch note compared with the version that I have, so you should ask for that mod to him if you are interested.



The sound has continued to improve over time and it never ceases to amaze me, especially in new situations like driving with the convertible top closed. While the drone wasn't the primary reason for installing this exhaust, now that I can enjoy the sound without any hint of it, I have come to appreciate it to such an extent that I wouldn't make the concession of having a drone in exchange for a high pitch sound at higher RPMs. It's easy to reproduce the drone because if I set the valves to always open, the BC Fabs exhaust will produce drone just like the Cargraphic did when flow passed through the X Pipe, however, as I've mentioned before, this exhaust is intended to be used with the standard valve programming.



I am increasingly convinced that there is no such thing as a perfect exhaust, but I believe this exhaust must be as close to perfection as possible.

lilbza

I mean thanks for taking the time to write a novel, but it's almost useless without sharing of video of how it sounds

Gabriel@NutCracker

I am running the CG X-pipe Track / Competition and i second that. I find the valves forced closed path of the exhaust practically useless. dB-wise (at least inside the cabin) the difference is marginal, but while the noise of valves forced open is quite pleasant (and it sounds like an exhaust), with valves forced closed the volume inside the cabin seems very similar if not higher and it's basically pure drone.

Thank you for the write up! Reading about the sound improvements of the below-4K range definitely is tempting, but I would probably never trade the high-pitched top end for it. To each his own obviously.

IRM

I run the X-pipe Racing and I am not giving up on that high-pitched wail whatsoever. It is one of the highlights of my Spyder

Rupert16

Beautiful workmanship!
I’d love this on my 22 Spyder, any sound bites available?

UncleDude

Two questions:

1. can you post a diagram over the exhaust with the valves open and closed path's shown? It is hard to tell from your photos.
2. is this a new design for him, or the old one? I think his old one valves closed would dump the gas out before mixing in the X (not 100% sure)

Thanks, I do like to geek out on the exhaust.

Larry Cable

or better photos so that one can figure out how the gas flows ...

UncleDude

Looks like his existing / old design (thought the OP’s might have been new)…. personally, I dismissed this one because the banks aren’t blended until the valves open. It is an interesting approach though, I’d love to hear one.

metalone

The valve closed path leads straight to the exit, bypassing the X Pipe, otherwise wouldn´t be possible to achieve zero drone on lower RPM. It also worth mention that this design cleverly accelerates gas velocity at lower RPMs using a smaller diameter pipe, while the larger diameter X pipe acts like a variable exhaust geometry when it´s needed.

In the initial design by BCFabs, they had a tangential X Pipe like this )(. However, Benjamin told me that the changed to a full X pipe cross to minimize turbulence and maximize the scavenging effect, despite being a more difficult manufacturing process.

Heres a video showing the exhaust:

• Youtube clip

metalone

I wanted to do a quick follow-up regarding this BCFabs exhaust. After 5 months, and including a track day, the exhaust's sound quality has noticeably improved from what was already great. I now hear a richer sound with pronounced burbles and intoxicating pops during playful, quick throttle responses, especially up to 4K with cold tires, after traction control kicks in.

Over time, this exhaust has truly enhanced its sound experience and perhaps also the ECU has learned the perfect tune for it. I won't be returning to Cargraphic for any reason now. This BCFabs exhaust is enjoyable across every band range and produces a progressively high-pitched sound at the top without being obnoxious.

Porsche Pato

That’s great and all but we still don’t know what it sounds like!!

AnandN

Thanks for the writeup. Do you have sound level readings inside the car at low and high rpms? I am a jazz fan and don't like loud sounds but a slight improvement in sound below 4k rpms would be nice. All these systems are quite pricey for me.
I assume it is this exhaust? https://www.bcfabs.com/product/porsc...-race-exhaust/

slm9555

How does the design of this exhaust compare to Kline?

MrFunk

Have you returned to 100% OEM Valve control?

MrFunk

I think that one has NO valves - that's the race exhaust. I don't think it's the one the OP has.
This is the one with the valves - https://www.bcfabs.com/product/porsc...alved-exhaust/