A new challenger in the starting blocks: a detailed look at the BMW M4 DTM for the 2017 season.

Munich. A month ahead of the first race of the year in
Hockenheim (GER), BMW Motorsport is very well prepared for the 2017
DTM. While the drivers and teams can call on a wealth of experience
as they go into the sixth season since BMW’s return to the
fiercely-competitive touring car series, the car is a newcomer: BMW
Motorsport lines up this year with the BMW M4 DTM, which has been
developed according to the new technical regulations.

 

With four titles in three years: the vehicle designation BMW M4 DTM
is synonymous with great success. Marco Wittmann (GER) won the
Drivers’ title with this car in both 2014 and 2016. BMW Team RMG also
picked up the Teams’ title in 2014, while BMW won the Manufacturers’
Championship in 2015. This year sees the dawn of a new era. In the
light of the new regulations, the BMW M4 DTM has been given a workover
and undergone significant development. The BMW M4 DTM now generates
over 500 hp of engine power, while the aerodynamics have also been the
subject of extensive modifications. Innovative technology was used
when manufacturing the components.

“We are very much looking forward to the new DTM season. The many
changes are primarily aimed at one thing: even more spectacle for fans
at the circuit and watching on screen,” said BMW Motorsport Director
Jens Marquardt. “I really like the new, more powerful cars. The
drivers at the wheel will make even more of a difference in the
future, and fans will get even closer to the teams and drivers at the
circuit. This combination promises to produce a thrilling season in
2017. Our engineers have worked hard over the past few months to
develop a host of detailed new solutions for the BMW M4 DTM, based on
the DTM regulations for the 2017 season. I am very proud of this team
effort. One of my personal highlights is the new look of the BMW M4
DTM. The blue crosses are a design element that originates from the
iconic BMW 3.0 CSL of the 1970s. Any DTM fan will also recognise the
blue crosses from the legendary BMW M3 DTM in the 1980s, when they
were still stuck on. In 2017, we do this digitally – as is also the
case, for example, with the new BMW 7 Series. We are looking forward
to the first race weekend in Hockenheim.”

 

Wind of Change.

The regulations required the BMW Motorsport engineers to take a new
approach to aerodynamics when developing the BMW M4 DTM. A shorter
diffusor and the fact that the ride height has been increased in line
with regulations, reduce downforce and ‘dirty air’. The flow topology
around the car was completely revised. The front bumper now has a
completely new shape and forms the starting point for the flow of the
air around the car. The wing mirrors will have a more conventional
design again in 2017 according to the regulations. Among the many
clearly visible modifications are the even more prominent contouring
of the side channel, the vent ducts on the rear wheel arches, which
are being used for the first time, and the incredibly detailed design
of the rear of the car.

The rear wing is also one of the more easily recognisable changes to
the 2017 DTM cars. The Drag Reduction System (DRS) has been modified.
Up until now, the rear wing consisted of just one profile and was
lowered as one part when DRS was triggered. The rear wing of the new
BMW M4 DTM is made up of two profiles, with the just the top profile
tilting upwards when DRS is activated. Unlike before, the end plates
no longer move with the wing. The range of adjustment for the system
is up to 40 degrees for 2017, making it more efficient than last year.

The front splitter and underbody of the DTM cars are standard
components, in accordance with the new regulations. The same goes for
the floor panel, which is five millimetres thicker than before. The
rear diffusor also has a completely new shape and is shorter and
flatter than that of the previous model.

Over the course of the aerodynamic development of the new BMW M4 DTM
in the BMW Group’s Aero Lab, the engineers had to be even more
efficient than usual: they had just 50 days in which to test the new
model in the wind tunnel and to optimise it. As a result, CFD
calculations, simulations and the rapid prototyping of components from
wind tunnel models played a more significant role.

 

Even more power.

When it comes to the engine, the DTM regulations for the 2017 season
allow a larger diameter for the air restrictors, through which the
engine draws in its combustion air. Having enlarged the air
restrictors from 2 x 28 millimetres to 2 x 29 millimetres, the charge
cycle was adapted accordingly. This increased the engine performance
by about 25 hp to over 500 hp. Because the engine, now known as the
P66/1, takes more cooling, due to the increased performance, the
cooling air intakes towards the front of the car were also modified.
As another consequence of the greater power, even more powerful and
durable carbon-fibre brake disks are also used in the DTM in 2017.

In its final spec, the BMW V8 engine consists of almost 800 different
components. In total, the powerhouse is made up of almost 4,000
individual parts. When designing the DTM power unit, BMW took full
advantage of the technological know-how of the BMW Group. The
high-tech foundry at the BMW plant in Landshut contributed the large
castings, such as cylinder heads and crankcases. The processing of the
castings, their coating, and any necessary thermal treatment, was
performed by the appropriate specialist departments in Munich.

BMW Power continues to be transferred to the track via a six-speed,
sequential racing transmission, which is operated pneumatically via
shift paddles on the steering wheel. It has eleven transmission
ratios, which allow the engineers and drivers to react to the circuit
and engine characteristics when setting-up the car.

 

Innovative technology for even greater efficiency.

The engine mount is a complex structural component, which is placed
under great strain, and connects the engine frame to the engine. It
was manufactured specifically for the DTM car using an additive 3D
printing procedure and optimised using topology.

BMW Motorsport engineers and their colleagues from BMW production
development have been regarded as pioneers in the field of additive
manufacturing for decades. Together, they are forging ahead with this
future-oriented manufacturing technology, increasing both the
efficiency and speed of the production of motorsport components. Since
2015, BMW Motorsport has used a water pump wheel made on a 3D printer
in its DTM engines. The high-precision component, which is subject to
high stresses, consists of an aluminium alloy and has proven its worth
in the tough motorsport environment.

The chassis for the 2017 DTM season consists of many standard parts:
shock absorbers, anti-roll bar, wishbone, wheel mounts, wheel hubs and
wheel nuts are now prescribed as standard. However, the BMW Motorsport
engineers had free rein when it came to the side springs and the third
element of the front axle, as well as the configuration and layout of
the standard parts.

The carbon-fibre monocoque is again instrumental in ensuring the
safety of the drivers in the new BMW M4 DTM. With an integrated tank,
steel roll cage, and additional crash elements, it provides effective
protection for the driver in case of an accident.

 

New conditions, lap by lap.

The interaction between the chassis and the 2017 generation of
Hankook race tyre was also of great importance. With a new design and
new compound, the DTM’s tyre partner is adding another exciting
element to the coming season. The new dry tyre for the DTM – the
Ventus Race – will generate greater grip than its predecessor when in
good condition. In contrast, however, it will degrade faster and more
dramatically, depending on the driving style. This is what the car
manufacturers and organisers had intended, and it will have a
significant effect on lap times.

Finally, new, characteristic LED front lights round off the
appearance of the 2017 model. They literally give the car a “dynamic
look”. The rear lights have also been redesigned.

 

Marco Wittmann discusses the BMW M4 DTM on video.

During the DTM tests in Hockenheim, DTM champion Marco Wittmann took
time out to explain the most important modifications to his Red Bull
BMW M4 DTM. You can find the video here: https://youtu.be/oLqhf0lxeLw.

You will find images from the DTM test drives in Hockenheim here: http://www.press.bmwgroup.com/global.

 

 

A compact look at the key modifications to the BMW M4 DTM.


 

Front:

Front lights: Blue crosses are a throwback to iconic BMW models on
the track and on the road – from the BMW 3.0 CSL and the
first-generation BMW M3 in the DTM to the current BMW 7 Series.

BMW P66 /1 engine: Increasing the diameter of the air restrictors has
boosted engine power to over 500 hp. As a consequence, further
modifications were made.

Flicks: Simpler design of aerodynamic attachments, in accordance with regulations.

Bumper: Re-designed front end including front splitter for efficient
airflow, based on changes to aerodynamics, as specified in the regulations.

Wing mirrors: Reduced aerodynamics in the wing mirror area, in
accordance with regulations.

 

Side:

Tyres: New Hankook tyre construction and compound. Generates greater
grip than its predecessor when in good condition. In contrast,
however, it will degrade faster and more dramatically, depending on
the driving style. This is what the car manufacturers and organisers
had intended, and it will have a significant effect on lap times.

Chassis: A number of components of the chassis and brakes have been
standardised, as have the wheel rims. However, the suspension
kinematics as well as the configuration of the dampers and springs can
still be adjusted individually.

Floor panel: The wooden floor panel is five millimetres thicker, in
accordance with regulations. This leads to a greater ride height, and
consequently to less downforce.

Side channel: As at the front and rear of the car, the air flow has
also been modified in the side channel.

 

Rear:

Rear wing: The DRS has been modified. The 2017 rear wing consists of
two parts, with the upper part tilting upwards when DRS is operated.
The system is generally more efficient.

Diffusor: The rear diffusor on the new BMW M4 DTM is shorter and flatter

than that of its predecessor, in order to comply with new
regulations. As such, it generates less downforce.

Rear lights: Design of rear lights in keeping with the design update
of the new BMW M4 Coupé.

Rear apron: Complete overhaul of the rear apron and adjustment to
suit modified flow topology – for example, due to new rear diffusor.

 

Technical Data BMW M4 DTM.

 

Dimensions:

Length: 4,725 mm

Width: 1,950 mm

Height: approx. 1,200 mm

Weight: 1,120 kg (in accordance with regulations, without driver,
dependent on performance ballast)

 

Engine:

Type:   P66/1, 90° V8 aspirated engine

Capacity: 3,999 cc

Weight: 148 kg

Bore: 93 mm

Stroke: 73.6 mm

Engine speed: max. 8,500 rpm

Performance: over 500 hp

Air restrictors: 2 x 29.0 mm, in accordance with regulations

Cylinder block and cylinder head made from cast aluminium at the BMW
foundry in Landshut; steel crankshaft; four valves per cylinder,
operated by bucket tappets; steel camshafts, driven by chains; Low
pressure, intake-manifold fuel injection, one injection nozzle per
cylinder; dry sump system

Acceleration: 0-100 km/h in 2.6 sec.

Top speed:     approx. 285 km/h

Tank capacity: 120 litres

 

Chassis:       

Carbon-fibre monocoque with integrated tank and steel roll cage;
carbon-fibre crash elements on sides; carbon-fibre crash elements on
front and rear

 

Transmission:

Sequential 6-speed sports gearbox, operated via pneumatic shift
paddles mounted on the steering wheel; 4-plate ZF carbon-fibre clutch;
adjustable multi-disc limited-slip differential

 

Front axle/rear axle:

Double wishbone suspension with struts and adjustable shock absorbers
(six settings); HR springs

 

Brakes:        

Hydraulic dual-circuit brake system; alloy, monoblock brake
callipers; internally-ventilated, carbon-fibre brake disks front and
rear; brake balance adjustable by driver; electromagnetic start valve

 

Wheels:

Aluminium forged wheels; 18” x 12” front, 18” x 13” rear

 

Tyres:

Hankook; front: 300-680-18, rear: 320-710-18 (new design and compound)