Mazda MX-5 NB Valved Exhaust System (1998-2005)

The Mazda MX-5 NB exhaust in detail.

The second generation of the roadster, the 1998 to 2005 MX-5 NB keeps the recipe that made the NA a success: lightness, rear-wheel drive, balance, and that Jinba Ittai connecting driver and car. Our data gives it 146 hp and 165 Nm, from a naturally aspirated four-cylinder that loves to rev.

In this philosophy, sound matters as much as numbers, and the factory exhaust keeps it muted. The Rog valved cat-back, also known as a valve exhaust, gives it a lively tone, an expressive climb and light crackles on the overrun when the valves are open; once closed, the NB becomes a relaxed roadster again for everyday journeys. Its NA and ND 2.0 siblings have other pages, and your NB’s serial number is checked before the system is manufactured.

Fitted with clamps and gaskets, without welding, the system takes about two hours in the workshop; the valves keep the factory control if there is one, otherwise the Rog remote operates them.

For those tuning their roadster, the page also sells, under the “Manifold” option, the front part carrying the catalytic converter; on a naturally aspirated engine of this displacement, a matching ECU remap remains a matter of a few per cent, roughly 3 to 8%, and the NB’s appeal lies elsewhere. An NB still used for Sunday drives will keep its emissions control with the 200-cell version, while a 100-cell will be judged according to the vehicle and your country’s rules and a decat part will remain confined to track use. That leaves the material: 304 stainless steel for those who drive in the rain and winter, titanium for those who count every kilo, with around 40% less weight.