Caffeine&Machine cultofmachine Yard Visitor The SR10: Radical’s lockdown project

The SR10: Radical’s lockdown project

While the rest of us were making banana bread, Radical Motorsport’s engineers were designing a best-selling track car over Zoom.

You could never accuse Radical Motorsport of not knowing its audience. Since 1997, the team has carved out a solid niche, cranking out track cars that look like baby Le Mans Prototypes, building a solid customer base of club- and national-level racers and wealthy individuals seeking out a taste of the motorsport experience.

Some have been road-legal, like the SR8 LM that was the fastest road car around the Nürburgring between August 2009 and September 2017. Others are track only. For many years, Radical employed either superbike engines or the unique RPE V8, created by fusing two Suzuki Hayabusa engines to a common crankshaft. Some have been strictly open-top, and there have been a few coupés. The basic formula is the same, though.

So no, the Peterborough-based manufacturer’s trajectory hasn’t exactly been – ahem – radical during its 25-year existence (not yet, anyway – some teaser images on their website for something called Project 25, slated for an unveiling later this year, suggest that might be about to change). But then it hasn’t especially needed to be.

That isn’t to say that the team has been completely resistant to change, though. In recent years, the it’s started using car-derived engines, starting with the RXC, a gullwing-doored coupé for road and racetrack. It was initially offered with the 3.7-litre Ford Duratec V6 alongside the RPE V8, and now exclusively features the 3.5-litre twin-turbo EcoBoost V6. Joining it are this, the track-only SR10, and the roadgoing Rapture, both of which employ a heavily tweaked version of Ford’s 2.3-litre EcoBoost four-cylinder.

Development of the SR10 was rudely interrupted, like pretty much everything else, by COVID in early 2020. While most of us were binge-watching Tiger King or pretending to pay attention during Zoom meetings, though, Radical’s engineering team decided to knuckle down and power through the unique challenges of remotely developing a car. Radical’s head of engineering, James Scott, recalls the process. “The engineering team said ‘let’s hunker down’, and try and get a product done, so that when we come out of this, we’ll have something to sell. We got stuck in working from home, and that was a battle, obviously.”

With all the UK tracks closed, the small cohort of engineers spent much of that summer on an RAF airfield putting vital development miles on the car. “Really, it was only three or four engineers that pulled it all together, and since then it’s proved a very popular car. It’s one of the fastest-selling Radicals – we’re up to chassis 110 now.”

James goes on to explain the decision to go down the EcoBoost route. “Cars like the SR3 and the SR8 have high-revving race engines, so have always taken a little more maintenance,” he says. “What we saw was a bit of a change in the market… customers asking for ease of use and longer service intervals. The automotive-based engine is the way to go on that, so we put in a heavily-modified version of the Ford engine – we now brand it as a Radical engine as much as we can. The recommended service interval on the engine is 80 hours – we used to consider 40 hours to be one season’s racing.”

The new turbocharged engine brings torque and efficiency gains, too. 425bhp and a kerb weight of 725kg mean 574bhp/tonne – this is what’s known in the trade as ‘a lot’. It’s all hooked up to a Hewland six-speed sequential gearbox. Designed to both be eligible for a number of race series, including the one-make Radical Cup, and for use as a track day toy, freedom from road regulations means that the SR10 packs some serious kit. The spec includes pushrod suspension with triple-adjustable dampers, a full FIA-spec motorsport fuel cell, and bespoke slick and wet racing tyres.

The next stage of the SR10’s development is the recently released ‘XXR’ variant, bringing a new aero package that can also be retroactively applied to the original car, and results in a neck-ruining peak lateral G of 2.3. Given the success of the ‘standard’ car, it’s safe to assume you’ll probably be able to catch an XXR at a racetrack near you soon, too.

The SR10 will be with us for our Lightspeed Weekend on 18 and 19 March, along with some more of Radical’s range and a few members of their team. Come check them out – tickets are online now.

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