The new Ariel Atom 4, the fourth generation of the high-performance sportscar launched in 1999, is the fastest standard version yet and has been entirely rebuilt from the ground up.

The Atom 4 will achieve 0-100kph in 2.8sec, matching its BAC Monorival, and 0-160kph in 6.8sec. The sportscar will make its public debut at this week’s Goodwood Festival of Speed, with deliveries starting by March 2019.

The Atom 4 uses the latest Honda Type R turbo engine delivering 324hp and gets a new chassis, suspension, steering, brakes and bodywork with significant aerodynamic improvements, as well as new seating and instrumentation.

Ariel Motor boss Simon Saunders said: “The Atom 4 is the biggest change to the car since we originally released it in 1999. It really is an all-new car. In fact, there are only three parts carried over from the last Atom: the clutch and brake pedals and the fuel cap.”

The basis of the Atom 4 is a new tubular chassis that's built in-house and features larger-diameter main and diagonal tubes than previous Atoms. Torsional stiffness has been increased by 15 percent, compared with the previous-generation Atom 3.5, launched in 2013. The chassis also promises more interior space and leg room.

Building on Ariel’s 15-year relationship with Honda UK, the Atom uses the latest Type R’s 324hp, 2.0-litre turbocharged engine developing 420Nm. That is a 75 percent increase in torque over the standard Atom 3.5 and a 35 percent rise over the supercharged Atom 3.5. Saunders called the deal “critical”, adding that “Type R engines have proven themselves in Atoms over the years with dependable power and absolutely faultless reliability, even under race conditions.”

The engine has been mapped by Ariel using an ECU developed specifically for the car and optional launch and traction control are now included, derived from the Atom V8. The Atom 4 is also able to adjust and optimise turbo boost levels for different road and track conditions. The fuel tank is larger than before, giving a range of almost 485km.

The Atom 4 retains the inboard, pushrod-operated damper system but features all-new suspension geometry with anti-squat and anti-dive intended to reduce unnecessary body roll and weight transfer.

This and the revised steering rack makes the Atom accessible for all types of drivers, said Ariel, and there’s the option of a quick rack for track-focused cars.

The model sits on 16-inch front and 17-inch rear wheels. Multi-spoke alloy wheels are standard but there is also the option of full carbon wheels for the first time. These are nearly 50 percent lighter than alloy wheels. The Atom 4 uses high-performance Avon ZZR tyres.

The company claims that the combination of the new suspension and larger-section Avon tyres contributes to the Atom 4 having more mechanical grip than any previous Atom and that cornering speed has moved to another level now.

There is also a new, larger braking setup to accommodate the extra power.

Ariel has done significant work to the body, with all-new panels improving aerodynamics. The most obvious change is the disappearance of the central Atom roll hoop, now enclosed under the air intake bodywork. The aero screen extends all the way across the car, reducing ‘helmet lift’ and directing air to the engine intake, and this aero fence is said to generate nominal downforce.

The company plans to make 100 cars annually, alongside its Nomad off-road buggy and Ace motorbike at its factory in Somerset. It will also be built under licence in the US, a vital market for the manufacturer. It will be the first Ariel vehicle to undergo a specific type approval that allows it to be sold throughout Europe and Australasia.