A no-compromise sportcar with the potential to become a class-winning GT racing car, the Invicta S1 is a luxurious Grand Tour, designed to be 2 cars in one. To achieve these often conflicting goals, the Invicta Car Company adopted several innovative approaches in both the design and construction phases of manufacturing its first car in modern times.
Design and Construction
The Invicta S1 is the world’s first car to feature a one-piece carbon-fiber bodyshell.
When bonded to the steel tube spaceframe chassis, the carbon fiber bodyshell creates a strong, yet lightweight, monocoque structure and results in a car with high flexional and torsional rigidity and excellent impact resistance.
The spaceframe chassis weighs 160 kilos, but the vast majority of that weight is low down, below the car’s roll centre. Made from 2 mm thick steel formed into 40 mm square tubes and cross-braced for maximum strength, the chassis construction uses TIG welding to give a smooth surface in the areas that are bonded to the bodyshell.
Engine and Performance
The desire to deliver no-compromise performance in terms of handling balance and sheer speed, the Invicta Car Company took the decision to mount the S1’s engine and gearbox well back in the 100-liter fuel tank transversely between the rear wheels, to achieve close to the ideal 50/50 front/rear weight distribution.
Filled with the Invicta’s own car air-intake and exhaust systems, the 4.6 and 5.0 liter engines powering the S1 range are supplied by Ford’s Special Vehicle Team (SUT) in America. Light, smooth-revving and ultra-reliable, these engines deliver stunning acceleration in the 1380 kg S1. Each engine is hand-built at Ford’s SVT facility and carries a plaque signed by the 2 technicians responsible for its assembly. However these engine’s may be upgraded by Invicta as necessary to produce up to 600 bhp. The completely flat floor of the S1 and the rising rear undertray give low-drag and generate downforce. Tests in the full size wind tunnel at MIRA confirm that the Invicta S1 will remain stable if driven at speeds in excess of 200 mph where road conditions permit. The secret for good fuel economy and wonderful performance is the combination of high power, massive torque and low weight.
Safety and Styling
The Invicta S1 spaceframe chassis is considered to be the strongest ever tested by UK car safety officials. The carbon composite semi-monocoque construction of the S1 bonds carbon fiber floor panels above and beneath the steel tube frame and also incorporates many safety features including: side-impact bars, rear-impact beam, seats positioned within the steel frame chassis, a full roll-over safety cage and keviar reinforcement of the doors, front and rear bumpers and windscreen surround.
The S1’s appearance was wanted to be a no-compromise sportscar in which performance and handling take priority, yet practicality and comfort are not forgotten. Engineers decided for bold proportions of a high body-side and a sleek glass area.
Transmission and LSD
Robust and reliable, the 5-speed manual gearbox, fitted to the S1-320 is a tough Borg-Warner T45 unit. It is mounted so far back in the S1 that the gear lever goes straight into the box top for a very direct, positive selector action. A six-speed manual transmission is standard in the S1-420 and in the S1-600. An automatic gearbox is a nil cost opinion in the S1-420. Drive from the from the front-mounted engine travels via the gearbox to the rear wheels through an Australian BTR hydratak viscous-coupling racing limited-slip differential.
Suspension and Steering
The Invicta S1’s major attributes are a stiff body chassis structure and balanced weight distribution. The S1’s suspension adopts a tried and proven classic layout and employs a pair of unequal length, double wishbones front and rear with anti-roll bars. Designed and produced in-house, the wishbones carry compact uprights developed jointly with AP and manufactured by Invicta. Specially developed suspension bushes from Powerflex ensure precise mounting of the wishbones, with sufficient insulation from road shocks to maintain good ride comfort. The coil springs and dampers are tuned to give the best possible blend of ride and handling. The dampers are easily adjustable for using the car on track days. Clients who want to exploit the Invicta S1’s undoubted race car potential, will find that camber, castor and anti-roll bar settings are all adjustable over a wide range. The power steering is beautifully weighted providing positive feedback to the driver and requires 3 turns of the steering wheel lock-to-lock.
Brakes, Wheels and Tires
The S1’s braking system with 4 large-diameter, cross-drilled and ventilated discs, is very close to a racing configuration, having AP 6-pot (front) and 4-pot (rear) brake calipers. The standard set-up uses anti-sequel brake pads and calipers for quiet operation in normal road use. A change of pad material will ensure the car’s use on a race track without running out of brakes. Being British designed and Italian made, the 5-spoke cast alloy wheels provide an aggressive compliment to the smooth flanks of the Invicta S1. the wheels of 19 inches in diameter, 8.5 inches wide (front) and 9.5 inch (rear) offer a clear view of the massive discs and their Invicta -branded brake calipers. The wheels are shod with ultra-low profile, 35 section, directional tires, in 2 widths – 255 (front) and 275 (rear) supplied by TOYO.
Interior, Comfort and Refinement
The Invicta S1’s role as a Grand Tourer has not been overlooked, although the vehicle has all the vital credentials to deliver maximum road and track performance. The double floor section between the wheels sandwiches a 40 mm layer of sound-proofing and throughout the car, great attention has been paid to isolating the occupants from the hardware and the heat it generates, but not from the thrill of driving.
The S1 is featured with a spacious cabin, with generous head and leg room. The supportive seats are trimmed to match the interior and offer a wide range of movements, together with adjustable lumbar support. The steering wheel is adjustable for reach and rake, and its 14-inch diameter rim frames an array of bespoke traditional instruments. The wide center console is trimmed in brushed aluminum and topped by triple air-vents. The cabin houses satellite navigation as standard, together with controls for the climate-control, air conditioning and the car audio equipment. Both front and rear windscreens are electrically heated and the S1 features a filler on each rear wing so that the fuel tank can be replenished from either side.