The weakest link - New BBR forged components for the SkyActiv 2.0

Posted by Neil Mckay on
The weakest link - New BBR forged components for the SkyActiv 2.0

 New BBR Forged Engine Components For the Mazda MX-5/Miata ND

13th April 2018

It’s safe to say we’ve put more into development and achieved more with the current generation of Mazda SkyActiv G engine than anyone. Way back in 2014 we began development on the current 2.0, turbocharged and developed camshafts before the UK had even seen the current MX-5/Miata ND!

Amazingly the SkyActiv petrol engine has a great deal of misinformation surrounding the tuning and its limitations, still now in 2018! Developing our own forced induction system for this platform it was clear to us we needed to make maximum power gains from the lowest possible boost pressure whilst keeping great torque gains in the low/mid range. Of course, achieving power gains like this is only possible with a turbocharger (not limited to output directly linked to engine speed like a supercharger).

Early developments revealed using a single scroll turbo significantly increased EGT’s and back pressure (this engine’s big enemy hence Mazda’s own 4-2-1 manifolds). We promptly decided to move to a twin scroll unit and never looked back, exceptionally low EGT’s and excellent response, just not possible from a single scroll (ball bearing included). It’s the current choice of Porsche, BMW, Mercedes, VAG, Ford and Subaru – their R&D dramatically outweighs the aftermarket! We believe the BBR ND turbo is the only aftermarket twin scroll turbo conversion for any marque? without a doubt for a Miata/MX-5.

Before the BBR stage one turbo conversion was released, we had tested not just one but three 2.0 SkyActiv engines to destruction. One in our trusty Mazda 3 and two others in MX-5’s! We had also burnt out countless clutches during testing. The result, some of our early turbo road tests had an inappropriate clutch fitted as it was our only option at the time! It was clear with our stage one turbo that we needed to be cautious with its output and unfortunately could not release it with quite as much power as our previous generation MX-5 NC conversion (we know from experience to keep things safe). Engine weakness aside the standard clutch will not take more torque than our stage one conversion. This resulted in our recent choice to use electronic boost control keeping the torque curve flat and peak torque below 230ftlbs.

Below pictures show just some of the dramatic results from 10psi of boost and over! This is the unfortunate reason why we have been holding back with further BBR turbo stages (we have two further engines like this from further stage development). Sadly, the SkyActiv has the weakest connecting rods we have seen! Do not be alarmed, our stage one operates safely at just under 7psi (around 230ftlbs). All in-house failures have been experienced at 10psi or higher (yes this is with safe AFR’s and zero knock, sadly we have another Mazda 3 engine yet to be taken apart with the same issue). Only now we are starting to see claims of around 300BHP from others whilst we have been there and have had the trophies for quite some time!

The good news, we have developed and produced our own parts again, teaming up with a leading European piston and connecting rod manufacture, we are proud to exclusively announce SkyActiv low compression forged pistons and forged connecting rods. Pistons are available for standard bores and +0.5mm. Our forged SkyActiv conrods are compatible with both standard and BBR SkyActiv forged pistons. Available as a piston and rod set at a reduced combined price or individually, let the next level of SkyActiv tuning begin!

We are delighted to have the parts to consistently run higher power levels (280BHP+) safely and will be shortly launching further BBR turbo stages (currently undergoing vigorous testing).


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19 comments

Created on Posted by Jack R.

Hello all at BBR GTi,
I love that you are taking initiative by producing proper internal components for aggressive forced induction (10 psi limit on stock internals is rather low in context of even stock applications these days) as no one else has done so yet. I do have to ask one thing though; are there any plans for forged 13.0:1 cr (or 14.0:1 cr for all non North American markets) pistons to be released by your company? I love your forced induction solutions, but I’ve always been interested in building the 2.0 Sky-G in the MX-5 for higher N/A power (maybe even custom ITBs hehe), and the revs required to go beyond even your super 200 kit may go beyond the piston speed limits of the stock hypereuteic pistons. I love the idea of a ND MX-5 with an almost S2000-esque N/A motor.

Best regards on your advancements!

Created on Posted by steven

Hi BBR GTi,

does this and turbocharged available install into CX-5 2012?

Created on Posted by Glynn Povey

Hi Neal, hope your well.
It’s great that you are working towards stage ‘2’ for the ND. I am really looking forward to having you transform my RF into the 300bhp+ monster. Although I had an interesting test drive, you didn’t put me off. Please keep me updated and let me know when you’re ready to start work. Ps did you get the white nd repaired.


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