Individual throttle bodies or ITBs might just be the ultimate naturally-aspirated tuning option. As well as looking and sounding incredible, this is in theory the ideal setup. With each cylinder getting its own throttle valve, the air doesn’t have to take such a long path to reach each combustion chamber, improving response. And did I mention the sound?
ITBs seems like quite an exotic modification, but there is now a new and very attainable way of doing it. Buy an NC-generation Mazda MX-5, wheel it into the workshop of renowned MX-5 experts BBR GTI in Oxfordshire, and part with a few thousand quid.
For £4295 the company will fully fit its new ‘Super 225’ kit, or if you’re happy to get your hands mucky, you can part with £3500 for a DIY version. For that, you’re getting a new exhaust camshaft, a four into one stainless steel exhaust manifold, CNC machined alloy inlet ram pipes, and yes, four billet 45mm throttle bodies. Some of that stuff is already in the Super 200 kit, onto which existing owners can get a simplified 225 add-on pack for £2495.
The result? Increases of 66bhp and 35lb ft of torque – hugely impressive gains for good old-fashioned N/A tuning, giving new totals of 225bhp at 7550rpm and 174lb ft 7450rpm. The redline also goes up a touch, with the fuel cut-off happening at a nicely zingy 7800rpm. And you’ll definitely be wanting to chase that figure as often as possible.
The 2.0-litre inline-four starts by making a noisy gargle at lower RPM, before belting out a furious bark in the mid-range that smashes through the cabin. Beyond 6000rpm, this turns into a glorious shriek of internally-combusted anger. What you hear is a blend of the Honda S2000’s F20 and perhaps an old Mk2 Ford Escort rally car with Weber carbs. It’s absolutely fantastic.
The increased range of the ‘LF’ engine means you are left wishing Mazda had kept the NC’s gears a bit shorter, however. As it is, the top end of second gear is around 60mph, so prepare to find yourself making excuses to slow down, shift into first and get an extra hit of the high-rpm delights.
If you’ve spent any time in modern turbocharged hot hatches, the Super 225 won’t feel outrageously fast, but it feels pleasantly quick, particularly when you’re chasing down that redline. The 0-62mph time is, we should think, somewhere in the six-second range.
This is a car you can fully enjoy on the road, making hilarious amounts of noise while remaining within sensible speeds. And, of course, it’s far more responsive than almost anything out there right now, if not quite as immediate as a car with an old-school cable throttle – it’s still a by-wire setup here.
The engine’s at its best beyond 4000rpm, but thanks to the additional torque, you don’t necessarily need to be spinning it that high to make decent progress. If you just want to get up to motorway speeds without dropping down a couple of gears and redlining it, that’s fine – there’s more than enough grunt in the lower part of the mid-range to allow for that.
It’s worth pointing out this Super 225 we drove does have a few other bits and pieces. There are stainless steel back-boxes, while the brakes have been upgraded with EBC Yellow Stuff pads, grooved discs, stainless steel lines and better fluid. The calipers are standard, proving just how good the stock NC stoppers are. You get loads of pedal progression, and plenty of power when the pressure is upped.
The key modification, though, is the set of Koni adjustable dampers. These drop down and stiffen up the NC nicely without wrecking the ride, and for £834, they seem like a must-have. I doubt you’d be able to enjoy all that extra performance anything like as much with the higher-riding, slightly floppy standard NC chassis.
All of this comes together to create the kind of driving experience I wish the aforementioned S2000 offered in its standard form. The Super 225 may not rev quite as high, but it’s a more dramatic engine, and a more flexible one. With the chassis tweaks, this NC also offers up more engagement.
It stacks up favourably against other modified MX-5s we’ve tried, too. The cam and ITB setup is far preferable to going the turbocharged route, and for the noise alone, the Super 225 is more memorable than the already hugely enjoyable ND-based Super 220. And against a Rocketeer NA/NB like Alex Kersten’s ‘Phil’, I had to reluctantly admit last year that his Jaguar V6-engined Mk1 offers up a dreamy driving experience. The Super 225, though, offers a similarly visceral, if quite different experience, and for a lot less money.
It’s still not hugely cheap once you factor in must-have extras like the suspension, but with NC MX-5s depreciating nicely, having one of these built is becoming more tempting by the day.