BMW 1 Series M Coupé – the DNA inside

BMW’s forthcoming F10-based M5 is almost upon us, with first deliveries expected in autumn 2011, but the real ‘Daddy’ of the M car range is the M3. In the true vernacular of the term such an accolade is usually bestowed on the quickest or most powerful model, but I’m using it in its purest sense – Daddy, as in father, the progenitor and main ancestor of BMW’s M DNA.

Now, you may argue that the first ever M car was the M535i which shared its 3.5-litre straight six engine with the BMW Motorsport developed M1 mid-engined Coupé and since a version of this engine spawned the very first E28 M5, this much surely reinforce the M5’s claim to be Pappa-M. But let me posit an alternative viewpoint.

Chapter 1: E46 M3 spawns E85 Z4 M

The twin pillars of BMW’s M DNA have always been engine and chassis – engines have traditionally been multi-valved, normally aspirated powerplants which achieve their peak torque via stratospherically high revs – but BMW are moving away from this idiom and all future M cars will be enhanced by forced-induction as introduced in the current X6M/X5M. So that leaves us with the chassis.

M3 CSL and Z4 M Coupe

The author's E46 M3 CSL and E85 Z4 M Coupe had much in common, but were uniquely different to drive. BMW re-applied this learning in the 1 Series M Coupé.

Since the 2002 E46 M3, BMW have become most adept in transferring the M3’s chassis and drivetrain into other M models. The E85 Z4 M was first to show the virtues of using such tried and tested technology, using both the engine and chassis of the E46 M3 – albeit with slight changes at the rear to accommodate the Z4’s more compact dimensions. Both models exemplified the M3’s uncanny drift-ability whilst maintaining distinctly different personalities.

So it was a pleasant surprise to find BMW had continued this trend with the new 1 Series M Coupé.

Chapter 2: E92 M3 spawns E82 1 Series M Coupé

It normally takes a car up to 60 months to reach the market from the first conceptual idea. The fact that things can move a bit faster has already been demonstrated by BMW M with the BMW M3 GTS.

M3 GTS and 1 Series M Coupe

When it came to the new BMW Series 1 M Coupé, progress was also very swift, thanks to the decision made to re-use many of the proven modular components already used in the M3.

Aluminium parts of the BMW 1 Series M Coupé's chassis.

“The kinematic qualities of the M3 were incorporated because the way in which the tracking and camber respond when deflected is just phenomenal,” confirms developer Jürgen Schwenker.

“The transverse link and trailing arm constructions had already undergone their baptism-of-fire in the BMW M3 and it was possible to do without the thrust panel, the aluminium support that reinforces the front of the BMW M3, because the inline six-cylinder turbo engine is even lighter than the already compact V8 engine of its bigger brother.”

[two_columns ]

“Despite the small wheel base and light weight, the basic coordination did not take very long,” remembers BMW M chassis expert Jürgen Schwenker.

The BMW Series 1 M Coupé was finally brought to life on the Nürburgring’s northern loop. Here too the pace was fast. Hence there were only three development passes for the bearing springs before the spring rate and level were right. “However, in order to balance comfort and sportiness, you need to be clear from the start how the final result is to look,” explains Schwenker.

As well as stabilisers and dampers, it was also necessary to adjust the supplementary springs (see yellow component in picture on right.) by means of the spring force and application points. When it came to the development work on the northern loop of the Nürburgring, a number of different teams were deployed in order to coordinate the various components, such as brakes, tyres, chassis and DSC.

[/two_columns] [two_columns_last ]Supplementary spring (yellow) of the BMW 1 Series M Coupé's chassis.[/two_columns_last]

In countless comparative outings the various components were tested in different variations until the perfect formula was found.

M Division : The future is in safe hands

One of the key points for chassis development is the northern loop of the Nürburgring, for example the Hatzenbach curve, where a sharp right hand bend follows hard deceleration. “If the car skitters about here and the wheels are in the air, then the ABS prevents the brakes from working. The car simply continues to roll forward,” explains Jürgen Schwenker.

M3 GTS on the Nurburgring

Tests in sector Hatzenbach of the Nürburgring Nordschleife (image: BMW M3 GTS).

“The brake zone before the “Aremberg” bend and after the “Schwedenkreuz” can create a similar issue. “These are points where you notice whether or not the distribution of the brake force is right.”

Many of the lessons learned on the M3 GTS therefore informed the tests used for the 1 Series M Coupé, further shortening the development life cycle and enabling BMW engineers to spend time optimising the car’s specific characteristics.

Despite the concerns of some enthusiasts over BMW M Division’s future engine strategy, it’s good to see that chassis development remains firmly on a path inspired by greatness.