Friday 21st April 2017

New BBR Mazda MX-5 turbo kit

Here it is! Latest MX-5 gets 252hp and 236lb ft from BBR's new turbo upgrade

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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?

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!

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...

[ben5575]

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]

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]

Well that's just sounds too much fun!

[geeks]

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

[Cupramax]

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

Direct injection no doubt, less issues with detonation due to precise fuel delivery.

[framerateuk]

ben5575 said:

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

I suspect not

They're entirely different propositions.

[Vitorio]

geeks said:

Voodoo and witchcraft

Undoubtedly, it makes me very happy that among all manufacturers just sticking turbos onto their engines and calling it a day, Mazda still sticks to squeezing more out of a screaming NA lump.

I dont know why anyone would go for the Fiat 124 with its turbo engine when you can get the mazda with an NA lump

[5harp3y]

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

better fuel / ignition control

[Regiment]

Vitorio said:

Undoubtedly, it makes me very happy that among all manufacturers just sticking turbos onto their engines and calling it a day, Mazda still sticks to squeezing more out of a screaming NA lump.

I dont know why anyone would go for the Fiat 124 with its turbo engine when you can get the mazda with an NA lump

The Fiat 124 is a much nicer looking car.

[Otispunkmeyer]

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

I thought it was 14:1, but maybe they lower it a little for the more powerful engines. I know the 120 hp version they put in the 3 is supposed to be 14:1

Anyway..... three things let them do this because even with NA engines you'd be running into issues that high if you didn't do something different.

1. Long 4-2-1 exhaust manifold. Stops hot gases from one cylinder appearing at the exhaust ports of a another. Keeps the in-cylinder charge temps down (away from auto-ignition).

2. Piston tops are not flat, they have a sort of pent-roof shape but then a flat bit on the top with a bowl cut into it. Imagine a simplistic drawing of a volcano. The purpose of this bowl really it to constrain where the ignition takes place. They want it to take place right in the bowl and not anwhere else. I.e. with auto-ignition/knock the mixture might start ignition at a hotspot else where on the piston top before the spark goes or end gases may go pop before the flame front reaches them. With this design they are confining the initial stages to a small space to reduce the likely-hood of the above. (that is my understanding anyway).

3. Direct injection. Its higher pressure than might be typical too and with a carefully designed spray pattern. Expanding fuel vapor introduced into the cylinder later in the compression has a cooling effect and gives it less time to get hot from compression. Again keeps the mixture down away from auto-ignition temperatures and delays contact with any hot-spots on piston/cylinder periphery.

If you like NA engines...don't fear Mazda has you covered. They are continuing this line with SkyActiv 2 which will be 18:1 and make use of HCCI combustion regimes.

[Vitorio]

Regiment said:

The Fiat 124 is a much nicer looking car.

Really? Id take the ND every day on looks, Fiat's hard-on for retro styling really isnt doing them any favours, and lets not even talk about what abarth does to that car in exchange for some extra boost.

[hornetrider]

Regiment said:

The Fiat 124 is a much nicer looking car.

[ben5575]

framerateuk said:

ben5575 said:

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

I suspect not

They're entirely different propositions.

I'm not so sure. I've had several caterhams over the past 15+ years for road/track/'ring etc and I love them. I also had an original BBR turbo in the '90's.

Caterhams are obviously great on track, but you really have to want to go for a drive in one on the road. A fantastic event sure, but it's a right faff on. Much like having to put your leathers etc on before going out for a bike ride. That and sitting at roundabouts, head below door handle height of cars, imagining getting T boned/rear wheel being smashed into your pelvis.

Ah crap, I've just realised I'm a hairdresser...!

[tankplanker]

Nanook said:

Because it's more powerful and faster. .

So it should be at another £5k over the top of the range MX5! With that £5k you could either pick up this turbo kit from BBR or stay NA their Super 200 kit with the exhaust replacement that makes ~210 BHP and be significantly faster than the Abarth with either option.

[Dakkon]

Nanook said:

Vitorio said:

I dont know why anyone would go for the Fiat 124 with its turbo engine when you can get the mazda with an NA lump

Because it's more powerful and faster. Probably better on fuel too, although I'm not sure about that.

It's not the one I would have, but you asked the question, that's the answer.

That's the wrong answer, every review puts the MX5 as the better car and on a racetrack the MX5 is the faster car.

[TaylotS2K]

If anyone buys this kit, don't have the naff BBR Turbo vinyls added.

[framerateuk]

ben5575 said:

I'm not so sure. I've had several caterhams over the past 15+ years for road/track/'ring etc and I love them. I also had an original BBR turbo in the '90's.

Caterhams are obviously great on track, but you really have to want to go for a drive in one on the road. A fantastic event sure, but it's a right faff on. Much like having to put your leathers etc on before going out for a bike ride. That and sitting at roundabouts, head below door handle height of cars, imagining getting T boned/rear wheel being smashed into your pelvis.

Ah crap, I've just realised I'm a hairdresser...!

I get what you mean, but that's why you have a car like an MX5 as a daily driver, and the Caterham tucked in the garage for early morning drives and trackdays.

There's a real sense of occasion strapping yourself into a proper harness, attaching the steering wheel and just going for a drive. You might only manage it a dozen times in a year, but Caterhams around the country sit in garages waiting for these days.

I'm sure a BBR Mx5 would go well (and this does look brilliant), but it doesn't have the special something that a Caterham has!

[Mr2Mike]

5harp3y said:

better fuel / ignition control

Primarily much better combustion chamber designs and optimised swirl/tumble and squish. Plenty of people turbocharger engines with 10:1 CR or more these days with no problems provided you don't go mad with the boost.

In the Mazda engine direction injection and efficient exhaust scavenging are the main enablers for the extra high compression ratio.

[ben5575]

framerateuk said:

but it doesn't have the special something that a Caterham has!

100% agree

[Bright Halo]

Just shows that Honda missed a trick not replacing the superb S2000.