Swap the restrictive factory cat for a freer-flowing performance catalytic converter that retains emissions equipment across the full 2003-2012 RX8 range.
$1,650 inc GST
The Mazda RX8 high flow cat from APEXi is a purpose-built performance catalytic converter for Series 1 and Series 2 owners. It replaces the stock unit with a less restrictive design, freeing exhaust flow without discarding emissions equipment entirely. That distinction matters: a high-flow cat keeps the exhaust compliant in spirit. A straight decat pipe does not.
For rotary enthusiasts, the clearest reward comes at higher revs. The Renesis responds well to reduced exhaust restriction. Swapping to a freer-flowing cat is one of the most accessible exhaust upgrades that still leaves emissions hardware in place. Expect a sharper, more defined exhaust note as flow improves through this section.
Pair this Mazda RX8 high flow cat with the HKS Hi-Power Cat-Back Exhaust with Titanium Tip or AUTOEXE Premium Cat-Back Exhaust Muffler for Series 1 and Series 2. For Series 1, the GREDDY TRUST Comfort Sports GT Slash Exhaust System is another cat-back option.
The ODULA Stainless Steel Exhaust Manifold is an exhaust header option for both series, ahead of the catalyser. Check the fitment of each component for your car before ordering. For more on APEXi, visit the APEXi official website.
Related RX8 Upgrades
Yes, the APEXi High-flow Catalyser covers the full RX8 range, fitting both Series 1 (2003-2008) and Series 2 (2009-2012) models. You don't need to source different parts for each series.
A high-flow catalyser uses a less restrictive core than a factory unit, allowing exhaust gases to pass through more freely while retaining catalytic converter function. For a rotary engine that breathes through every revolution without a traditional piston intake cycle, reducing exhaust restriction is a meaningful part of an exhaust build.
Yes, the APEXi is a catalytic converter replacement, not a decat pipe, so your emissions equipment remains functional. This avoids the drone and emissions compliance issues that can come with a full decat setup.
The APEXi is designed as a purpose-specific RX8 component and is well suited to pairing with an aftermarket cat-back system. Matching a high-flow catalyser with a free-flowing cat-back addresses restriction at both ends of the mid-exhaust section for a more cohesive build.
Catalytic converter replacement involves exhaust system removal and, depending on your setup, may require a tune or at minimum an oxygen sensor reset. Professional fitting is recommended to ensure correct sealing and to address any remapping requirements.
A remap is not always mandatory when fitting a high-flow catalyser in place of a stock unit, but it is often recommended to take full advantage of the reduced exhaust restriction. Consult a rotary-experienced tuner to assess whether your current tune remains appropriate.
The APEXi is a product designed specifically for the RX8 exhaust system rather than a universal fitment unit adapted to suit. A purpose-built component from an established Japanese performance brand offers more confidence in fit quality and consistency than an unbranded generic alternative.
