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Catalysts and exhaust systems for Motorsport and Tuning

Since 1990, HJS has been developing and producing catalysts and exhaust systems. For more than 10 years, HJS has refined its experience with motorsports applications. Today you can equip your own street vehicle with high performance tuning catalysts by HJS!


HJS tuning catalysts with 200 cpsi were developed using technology proven on the racetrack. The product range extends from downpipes with ECE R103 approval to ECE catalytic converters to universal catalysts.

HJS customers are amateur sportspeople, work teams, hobby tuners and vehicle manufacturers. They recognize HJS as an efficient, service-oriented company.

HJS is built on

  • Innovative technologies and products

  • Customer satisfaction

  • Long-lasting business relationships

  • Important contributions to the protection of  humans and the environment.

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Exhaust passing through a standard catalytic converter may encounter restrictions that will slow down the flow of gasses.  High performance vehicle enthusiasts who have made investments in upgrades to increase engine power will look for a catalytic converter that is tuned to offer the most efficient flow and optimum backpressure. The goal is to ensure engine output won’t be constrained by exhaust gas flow rates.     

HJS Catalytic Converters are a premium catalytic converter solution for customers looking to enhance sound and flow – all without a check-engine light for Imported models (for domestic models, we cannot guarantee a switch of the check engine light, but it will pass emissions tests).  

HJS cats are praised by enthusiasts as the highest-grade catalytic converters on the market. HJS Catalytic Converters are considered to be OEM++, performing equal to or better than the original.

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