Built by BMW’s motorsport subsidiary BMW M GmbH, the M3 GTS has been developed primarily for club-racing, while also meeting type approval for the road.
The GTS is not a new model, but a development of the standard M3. Changes are substantial, though: tweaks to the bodyshell improve aerodynamics and save weight, revised running-gear is aimed at improving handling on a circuit, the dual-clutch transmission is recalibrated, and — most significantly — the engine is effectively a new unit.
Displacing 4361cc, the new V8 has gained 62cc by virtue of a longer stroke: 82.0mm instead of 75.2mm. It has also gained 30PS and 40Nm, with the torque peak at a very un-motorsport 3750rpm. The power peak is at 8300rpm.
BMW M3 GTS.
The engine is otherwise unchanged from that of the standard M3. Features include a crankcase designed with a bedplate construction and cast from an aluminium-silicon alloy; an individual throttle for each cylinder; and knock sensors using ionic-current technology. The engine uses a conventional wet oil sump.
The GTS has its own lightweight exhaust system, with unique primary catalytic converters and titanium rear silencers that present a low back-pressure.
Power is transmitted to the road by way of a modified version of the M3’s gearbox. It’s a seven-speed dual clutch unit known as M Dual Clutch Drivelogic; like other dual-clutch gearboxes, it is designed to change gear without loss of tractive force.
Suspension is substantially modified. The GTS uses a rigid rear axle support and coilover suspension. The dampers are independently adjustable for travel, botj on load and unload. Front and rear camber can be adjusted, as can ride-height. The standard ride-height is 16mm lower at the front and 12mm lower at the rear compared with the standard M3.
A fixed-calliper braking system has been adopted for the M3 GTS. Six-piston calipers are used at the front, with four-piston items at the rear. The brake discs are 18mm larger in diameter at the front and 30mm larger at the rear compared with the standard car’s set-up; steel-armoured hoses are used.
The M3’s Dynamic Stability Control has been modified to allow for the greater performance of the GTS.
To improve the M3’s aerodynamics for racing, and also to make the airflow adjustable to some degree, the GTS is fitted with a racing-orientated front apron and rear wing. These allow the car’s aerodynamics to be tailored to an individual track. The air ducts in the front apron are variable, as is the position of the rear wing. The tail assembly is based on that of the World Touring Car Championship BMW 320si.
There are a number of extra weight-saving measures. As well as the standard car’s CFRP roof and the titanium rear silencers we’ve already mentioned, the centre console and door panels are built very light, and polycarbonate is used for the rear side windows and the rear window. There is no rear seat, and acoustic insulation is (as BMW puts it) ‘configured specifically for the vehicle’ — there’s not much, in other words. The DIN kerb weight of the BMW M3 GTS is 1530kg including its roll-bars — 70kg less than the standard M3. The automatic climate control and audio system which are standard kit on the normal M3 are optional extras on the GTS.
The interior features racing bucket seats. The GTS is equipped as standard with a roll-bar fitted behind the B-pillars. The body has fastening points for six-point safety seat belts and an optional extension for the roll cage. As standard, three-point automatic seatbelts are fitted, but six-point safety seat belts for both front seats and a fire extinguisherare also supplied.