Fabspeed Motorsport
McLaren MP4-12C High-Performance Exhaust Systems



Fabspeed Motorsport is the World Leader in high performance exhaust systems for exotics, supercars, and hyper-cars. Fabspeed Motorsport was the world’s first company to develop a super high-performance exhaust system over a 15 months ago for the McLaren MP4-12C cars. Since then Fabspeed Motorsport has continually developed and refined the Fabspeed Maxflo Sport/Racing Catalytic Converters and Supersport X pipe Exhaust with stock style oval exhaust tips. Fabspeed also designed very cool deluxe Quad Tips for these wonderful cars. Fabspeed Motorsport USA has more long-term experience with these McLaren Twin Turbo Coupes and Spiders than any other tuning company in the world. No other company in the worldhas the depth of experience and development of X pipes as does Fabspeed Motorsport USA.

After the McLaren Heritage Orange coupe was fully baseline tested and disassembled, it was discovered that the McLaren OEM catalytic converters were very short in length. These factory cats were extremely short so that exhaust gas could pass through efficiently and quickly to maximize power. In addition, McLaren engineering in the United Kingdom placed the oxygen sensor port locations in very close tolerance to these proprietary catalytic converters because the McLaren heat shields must cover these extremely short catalytic converters, oxygen sensor bungs/ports and all 3.0” 76mm tubes for maximum exhaust efficiency and to minimize radiant heat.

Essentially, McLaren has a clamshell heat shield that wraps around all the catalytic converter pipes and is fastened to the OEM catalytic converters. Fabspeed worked with Solidworks engineers to model the flow of the stock OEM exhaust, model the $6300 optional McLaren “sport exhaust” and the refined Fabspeed Motorsport systems throughout all MP4-12C development.


Above: Solidworks flow analysis of the stock MP4-12C exhaust system.

Fabspeed Motorsport logically and initially designed these systems to utilize a 200-cell sport/racing catalytic converter that we had previously used on our super-high horsepower, world famous Porsche 997 Twin Turbo sport exhaust systems. The logical hypothesis and assumption, in conjunction with off-the-shelf thinking, was that these large round long HJS 997.2 Twin Turbo catalytic converters could support 800HP, so therefore they would support the 650-800+ horsepower of the 3.8L McLaren Twin Turbo engine.

Fabspeed’s engineers were able to make this cat fit and work with a lot of tedious work, but the super-long 997 Twin Turbo catalytic converters did not fit properly and there were too many complications and outright negative compromises that limited the performance and durability. In other words, the 997TT catalytic converter and other off-the-shelf HJS catalytic converters that Fabspeed Motorsport utilizes for other supercars were much too long and too big to fit correctly, and Fabspeed had to bastardize the catalytic converter and compromise the symmetry of the inlet and outlet pipes to make the 997.2 Twin Turbo catalytic converters and other off-the-shelf HJS catalytic converters fit. Fabspeed Motorsport USA and HJS Germany mutually decided that forcing or manipulating a 997TT catalytic converter that is over 32% longer than a stock McLaren primary catalytic converter to fit was the WRONG solution for the McLaren Twin Turbo, which must meet Euro Level 5 emissions.

Faced with this unique challenge, Fabspeed Motorsport called HJS headquarters in Germany and discussed the parameters and the issues that had become apparent. Joe Fabiani, the president of Fabspeed, spoke with Klaus Osterhaus and HJS racing engineers and then Joe Fabiani paid for the tooling, engineering, and development of an ultra-high-flowing 300-cell HJS catalytic converter specifically for the McLaren MP4-12C cars. Fabspeed Motorsport is HJS Germany’s largest volume customer in North America and South America, and HJS provide this super high-flow short 300CPSI catalytic converter – as an exclusive – to Fabspeed Motorsport. These Fabspeed Motorsport HJS MP4-12C specifically designed and engineered cats match up perfectly to any stock or aftermarket McLaren rear muffler system.



Fabspeed Motorsport’s compact 300CPSI tri-metallic OBD2 EURO Level 5+ certified proprietary catalytic converters fit precisely, and as expected given their short length, significantly outperform the 32% longer and incorrectly-fitting 200-cell 997TT cats in back-to-back testing. From exhaust flow to power gains and 300CPSI cats also have a 50% more precious metal coating and stronger core structure so the Fabspeed McLaren cats are better under any and all engineering based criteria.

This is logical, given that Fabspeed Motorsport USA took a blank sheet of paper and partnered with HJS Germany to develop, at great expense, a dedicated and bespoke catalytic converter for the wonderful new-at-the-time McLaren MP4-12C cars. The Fabspeed Motorsport bespoke McLaren catalytic converters are HD directional, 50% stronger than 200 cell HJS 997TT catalytic converters. The Fabspeed 300-cell McLaren catalytic converters also cost significantly more in terms of custom-tooling and precious metal wash coating/loading materials than did the standard off-the-shelf Porsche 997TT catalytic converters. After more than 20,000 combined miles and over 60 systems installed, not one CEL light or failure has been reported on Fabspeed ultra flow McLaren catalytic converters.



This in-depth research, development, engineering, and testing led Fabspeed Motorsport to market their new system with the specifically-designed 300-cell cats, instead of the 200-cell versions that are in use by their competitors’ systems. Fabspeed was the first company to design and use 200-cell HJS cats, but quickly realized that 200-cell cats were a weak unacceptable compromise for deployment on the McLarens.

As clearly mentioned above, the bottom line for Fabspeed Motorsport USA and HJS Germany is that the extremely long 200-cell cats were not suited for many qualitative and quantitative reasons. The final conclusion was that given the MP4-12C’s exhaust geometry and flow pattern, that the Fabspeed-exclusive 300-cell HJS HD Level-5+ cats were – and are – the premiere performance option for these cars.


  • • Fabspeed Motorsport was the first tuner in the world to design and dyno-develop proven high-performance exhaust systems for the McLaren MP4-12C Coupe and Spyder cars
  • • Fabspeed has over 14 months of street, track, dyno, and empirical testing on the McLaren MP4-12C platform.
  • • Fabspeed Motorsport’s systems have logged over 20,000 miles of proven durability.
  • • Fabspeed’s McLaren systems utilize exclusive proprietary HJS Tri-Metallic OBDII European Level-5 Ultra-Highflow Catalytic Converters (specifically designed by HJS for Fabspeed Motorsport). No other company has these cats for the McLaren cars.
  • • Fabspeed’s systems were designed and modeled in CAD and testing was performed using finite element analysis and flow analysis, completed with SolidWorks (a unit of Dassault Systems in France).
  • • Fabspeed Motorsport USA is the North and South America's largest importer of German HJS Catalytic Converters and number-two in the world for developing high-performance exotic and supercar exhaust applications using HJS Sport Cats.

Fabspeed Motorsports USA designed the ultimate McLaren stainless steel exhaust systems and components using passion and engineering that can not be copied!