BBR Mazda MX-5 Supercharged

Engine upgrade promising up to 250bhp brings new levels of excitement to the Mk4 MX-5

- ADAM TOWLER

BBR'S PORTFOLIO OF MX-5 CONVERSIONS continues to grow with this, a supercharger kit for the 2-litre 'ND' (MK4) car in its original, 158bhp form, as built from 2015 to 2019. BBR is working on an installation for the later, 181bhp ND models too, but for the 158bhp engine the kit is available in two stages of tune: Stage 1 being the core and Stage 2 improving the engine's breathing to liberate even more horsepower and torque.

The heart of the conversion is the fitment of a Rotrex C30-94 supercharger - and very neat it looks too under the bonnet, where you'd be hard-pressed to notice this is a modified car and not as it left the production line. The kit includes an oil cooler, intercooler, and K&N air filter, along with a long list of smaller parts, and is governed by a new map for the engine's ECU. The result is 'at least' 220bhp (BBR quotes this figure as a minimum, with 225bhp expected) joined by 200lb ft of torque (up from 147lb ft) delivered on a plateau between 3750 and 5750rpm. A glance at the power and torque curves plotted on a graph suggests the characteristics of the standard engine have been retained, but with simply more of everything, everywhere.

Moving to Stage 2 means adding BBR's stainless steel exhaust, from the 4-1 manifold via the sports cat to the rear silencer and tailpipe. This liberates 240-250bhp in total, with 220lb ft of torque, plus you can add a larger Forge Motorsport intercooler if you're really going to push the car hard in high ambient temperatures, such as at a summer trackday.