You’re looking at the ultimate track weapon. This is the SR-10, a 425bhp, 725kg race car slayer that Radical reckons will out-pace and out-smart a GT3 car on the track. With 586bhp per tonne, and an aero package that makes a Formula One car look tame, we take a tour around the “torque monster” with Radical’s technical development manager James Scott.
James, on paper the SR-10’s figures are crazy. What are some of its key features?
Yeah, the SR-10 sits at the top of our SR family of cars and is our most powerful yet. We’ve sold quite a few already and it’s been one of our most successful launches. It has a lot of new parts, including a new engine; a Radical performance Engines’ version of the Ford 2.3 EcoBoost. They start at 270bhp but by the time we’re done with it we’ll get 425bhp out of it. It’s a really strong motor and is the essence of the car. Paired with that we’ve also got a brand new six-speed sequential gearbox from Hewland. Together, you get a really powerful endurance package. The SR-10 also uses our proven strong and lightweight steel tube chassis. One of the other new things with the car is its electronics package, which includes a new all-in-one Formula One-style steering wheel. That brings a bit of excitement for the driver.
Can you put that performance into context for us?
You could say it's the ultimate track-day car. It’s a true two-seater, which is unique in the market. It’s probably the quickest two-seater you can buy, quicker than GT3 and touring cars. A GT3 race car will set you back several hundred thousand. We are a fraction of the cost. It’s probably the fastest thing out there before moving up to professional racing. We sell them to a range of customers who want to do track days and overtake absolutely everything else, as well as people who want to take part in our own race series.
How do customers feel when they first get into the SR-10 and how quickly does it take them to get up to speed?
The thing with Radicals is we always try and make them accessible. Part of the development of this car was to have a range of different maps. So, it has a manettino switch that allows you to vary the power output. You can start off on a lower power setting and build it up as you get more confident. When you’re hopping into a car like the SR-10 from a normal road car, the first thing you notice is the level of feedback. It’s confidence inspiring.
Power to weight ratio is the holy grail for a performance car. How difficult is it to achieve that and how do you manage to get so much out of the SR10? Is this what makes the car so special?
Power to weight is everything. And it’s quite easy: you want the most power and the least weight – and with the SR-10 those two things are in abundance. We’ve taken the most powerful engine in the SR range and paired it with the lightweight chassis of the SR car. It really gives you kick in the back when you accelerate. One customer recently called it a torque monster.
How much of a role does downforce have to play in this car?
Yeah, Radicals are very much aero cars and is the reason we’re so quick through corners. With the SR-10, we’re not only quick through the corners, but on the straights as well. So strong engine and brakes and lots of downforce is where the fast lap times come from.
How important are lubricants in a car like the SR10? From an engineer’s perspective, what makes Motul’s lubricants better suited to the SR10?
Motul’s lubricants are great. We use everything from the brake fluid, clutch, gearbox and engine lubricants. The durability and performance have been no issue at all. When we started out with Motul it was at the same time as we brought in a new engine. For a high compression, direct-injection engines, we need to use a special oil, and we found that right away with Motul. For us, the global availability is another huge benefit of using Motul. We’re selling cars all across the Americas, Europe, and Asia. So, to have global dealerships where our dealers can stock a really good quality lubricant is key for us.