► Cosworth ‘stage 2’ kit available for BRZ and GT86
► Complete supercharger and cooling package
► Exhaust and brake upgrades offered too
‘Oh, that’s one of those Subaru-Toyota coupe things. BRZ or GT86, isn’t it? Heard they’re good to drive, but a bit slow. Wait a minute… is that Cosworth badge real?’
It is, my friend. It really is.
There’s a Cosworth GT86 now? I thought Cosworth only did Fords...
Hold your horses. This is not the official injection of performance we’ve long been craving, but an upgrade kit developed by Cosworth on its own behalf. This is far from being the first of its kind – in fact, as Cosworth readily acknowledges, it’s rather late to the party – but the Cosworth pedigree is so hard to ignore we just had to take a closer look.
This isn’t the Northampton-based F1 engine builder’s first foray into the Japanese performance market, either. After all, how could you forget the 395bhp Subaru Impreza STI CS400, which was sold as an official UK limited edition run of 75 back in 2010. At 50 grand a pop.
Please tell me the Cosworth GT86 isn’t that expensive?
Heavens, no. Rather than build a whole car, Cosworth is offering packages of parts to giddy-up boggo versions of the ‘FA20 platform’ – nerd-speak for that which underpins both Subaru BRZ and Toyota GT86.
Stage 1 kicks off with an air filter, low-temperature thermostat (Cosworth says the standard cars run performance-limiting higher temps for emissions reasons) and an ECU remap, and this alone is good for an extra 15bhp. You can supplement this with three stages of exhaust system upgrade; total power hike in the region of 40bhp.
But the car we’re dealing with here is the Stage 2 version. Stage 2 is a forced-induction setup, comprising custom intake manifold, intercooler, low temperature radiator and positive displacement supercharger – substantially boosting power and, more significantly, torque. It’ll cost you around £4794 including VAT, and an approved fitter will get the job done for about £400-£500.
With used prices for the GT86 now starting at under £15,000, you could build one of these for £20k. About the same amount of money as a high spec Fiesta ST.
What’s the power output of the Cosworth GT86?
Equipped with the full Cosworth exhaust system (£3768 for manifold, mid-pipe and cat-back), a single free-flow catalytic converter (rather than the standard two), and all the supercharger gubbins, the demo car is putting out around 290bhp and 243lb ft of torque.
A standard GT86 produces 197bhp and 151lb ft; the Cosworth is making almost that much twist at 1500rpm…
Hmm. This is all starting to sound a bit Chav Power – does it drive that way, too?
You’re getting distracted by the decals; put those out of your mind.
Cosworth has deliberately designed the supercharger kit to be as OEM as possible – from the gorgeously finished installation components to the power delivery. There’s no sudden spike of torque, and the engine still likes to rev and still makes maximum power at 7,000rpm.
The difference – and it’s a big one – is that you no longer need to bounce it off the limiter in order to keep up with turbodiesel commuter traffic.
Power comes in smoothly, but just keeps on coming, while the extra torque means you can cruise in a much higher gear and still make rapid progress – not to mention overwhelm the rear tyres at will. And that’s with larger diameter and far stickier rubber; the bigger wheels necessary in this instance to clear the monster Cosworth-AP Racing brake kit (£2100).
0-62mph is estimated at under 5.0sec. And in case you’re worried, the car retains operational stability control.
What about reliability? Isn’t all that extra oopmh going to blow up the engine?
Cosworth reckons not. This particular GT86 has been running the supercharger for over 12,000 miles. The kit is deliberately within the tolerances of the standard engine components; the supercharger and associated cooling package are actually good for nearly 400bhp, but to achieve that you’ll at least need to look at replacing the rods (especially) and the pistons.
The test car even comes with four ECU maps, accessed via double-purposing the cruise control stalk. Pull and hold, and the rev counter leaps to the number on its dial that corresponds with the current setting, and you simply move between them by nudging the cruise stalk up and down.
Map one is for 95ron petrol, which costs you about 15bhp. Map two is for 98ron, map 3 adds a more aggressive throttle map, and map 4 switches on what Cosworth calls ‘the toys’ – principally launch control and a flat-shift capability. The ability to flat-shift means you can keep the right pedal pinned while changing up for the fastest possible acceleration and some excellent noises.
It can’t all be good, surely?
Two things we weren’t keen on: the Cosworth exhaust, which gets a tad too boomy and resonant on the motorway, and the suspension. You’d live with the former, but we’d need to do something about the latter – this isn’t Cosworth’s anyway.
Rather, it’s a KW coilover kit, which typically for coilovers gives a choppy ride and little finesse. It’s also possibly been set too low, though, as thoughts of seriously spanking the car over local B-roads were quickly quashed by it bottoming out. Shame, because some of the other detail changes to the chassis – the odd bush, here and there – actually work quite well.
Cosworth GT86: verdict
Got a Toyota GT86 or Subaru BRZ, or thinking of buying a used one? Want more power? Then this seems a fair place to start – the supercharger significantly redresses the standard torque gap and comprehensively retains usability. How an unmodified chassis would cope we can’t tell you, but at the very least you’d best budget extra to replace those Prius tyres…