ND MX-5, but now it's time for the big power gains with this turbo kit. While the numbers will invariably be first priority - 252hp at 7,150rpm, 236lb ft at 3,250rpm, 155mph and 60 in five seconds - the development of this turbo installation is very interesting too.
Why no supercharger? It doesn't work well with the Skyactiv-G engine, BBR's Neil McKay citing "high parasitic losses" as the problem. The charger would need a lot of boost for the power gains, which would be incompatible with the standard MX-5's high - 13:1 - compression ratio. A single-scroll turbo was also rejected; the 4-2-1 exhaust manifold of the MX-5 is very complex, to exploit exhaust scavenging technology, but a single-scroll turbo creates a lot of back pressure and lacks any potential for exhaust scavenging.
Therefore a low pressure twin-scroll turbo has been used, said to work "harmoniously" with the standard engine and delivering good power with modest boost pressures. The Stage 1 conversion runs at 7 psi, with a bespoke billet compressor and low inertia turbine for the best response possible.
The engine's internals are untouched, with the additional tweaks as part of this kit comprising a new exhaust manifold, a stainless steel downpipe, an intercooler, a dump valve, a K&N induction kit and an upgraded Starchip ECU. The various pipes and lines around the engine have been switched too.
And the price? £4,395 plus VAT, or £4,995 as a 'drive in, drive out' kit at BBR in Brackley. The cheapest 2.0-litre available on PH at the moment is this Soul Red car at £17,750. And if just 250hp simply won't do, then let BBR have the last word: "With internal upgrades to the Mazda engine we know that considerably more power is available - the BBR technical team is already developing future stages to exploit this." We'll keep you posted...