New BBR Mazda MX-5 turbo kit


Much of the MX-5 legend is built on its tuning potential, the scope to create pretty much whatever two-seat roadster you want from the aftermarket a very appealing prospect to a lot of owners. And for PH tastes, the work of BBR is always of interest.

Well why have you stopped driving?
Well why have you stopped driving?
We've already experienced (and enjoyed) BBR's naturally aspirated tuning on the 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.

POWER!
POWER!
BBR also claims that all Mazda electronic features are retained, with MOT emissions compliance guaranteed and warranties from 12 to 36 months. The kit is fully reversible as well.

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...

P.H. O'meter

Join the PH rating wars with your marks out of 10 for the article (Your ratings will be shown in your profile if you have one!)

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
Rate this article

Comments (32) Join the discussion on the forum

  • ben5575 6 days ago

    Now we're talking.

    When do you have a test drive/video planned?

    It would also be helpful if you mention the price of the suspension, wheels, exhaust upgrades in the article as well (or the follow up) so we can get a flavour of the cost of a 'complete' BBR conversion.

    An 'affordable', warrantied and convenient 250bhp/ton 2 seater is a very seductive proposition. I suspect Caterham may be getting a little nervous.

  • 998420 6 days ago

    Can someone please explain how.come a 13:1 compression ratio does not need lowering to under 10 to cope with the turbo boost?

    With bike engines in the 90s,people were sticking extra gaskets below the barrels, or thicker head gaskets, or low comp. pistons (around 8:1) to get compression below 10:1

  • great_kahn 6 days ago

    Well that's just sounds too much fun!

  • geeks 6 days ago

    998420 said:
    Can someone please explain how.come a 13:1 compression ratio does not need lowering to under 10 to cope with the turbo boost?

    With bike engines in the 90s,people were sticking extra gaskets below the barrels, or thicker head gaskets, or low comp. pistons (around 8:1) to get compression below 10:1
    Voodoo and witchcraft hehe

  • Cupramax 6 days ago

    geeks said:
    998420 said:
    Can someone please explain how.come a 13:1 compression ratio does not need lowering to under 10 to cope with the turbo boost?

    With bike engines in the 90s,people were sticking extra gaskets below the barrels, or thicker head gaskets, or low comp. pistons (around 8:1) to get compression below 10:1
    Voodoo and witchcraft hehe
    Direct injection no doubt, less issues with detonation due to precise fuel delivery.

View all comments in the forums Make a comment