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      11-18-2013, 11:16 AM   #1
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Post BMW M4 - Sport Auto test ride and interview with Albert Biermann

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Picked up German magazine Sport Auto today. It features an interview with BMW M development chief Albert Biermann and a ride in the M4 with Biermann driving.

This is my translation of the major parts of this article. My apologies for bad sentences or missed meanings (I have tried my best from a hotel room after a long day at work...):

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They start the article with an observation that Biermann seems a bit anxious and how he fires up the six cylinder and revs it, firing off a couple of “raw six cylinder salvos”.

On handling:
“No BMW M base model has been developed so consistently for track use as the new M3/M4. It has not been so much about raising the power over the previous model, but to lower the weight and get a coherent overall concept.”

The M4 should reach more than 300km/h, but that is only half the story. The other half is how it corners. The double joint front suspension has lost 5kg. Tolerance free joints and bushings increases stability. The rear suspension is mounted directly to the body. The active rear diff is taken from the M5/M6.

On weight saving:
The new car will weigh under 1500kg (in base version). The propshaft in CF saves 5kg. The electrical steering saves 3kg over the hydraulic system.

On electrical steering:
Biermann acknowledges that “to many, electrical steering is a “devils tool” but to us the weight saving of 3kg was a argument. We are also aiming to have a self-correcting, undetectable steering assistance”.

“We want to have the best electro mechanical steering in the car that money can buy”. It was also a factor that the base cars have electro mechanical steering and that it was a clear objective to use BMW M budgets on weight reductions instead of developing a dedicated hydro mechanical steering only for the M models.

On the engine:
The S55 will be assembled on the regular production line in Steyr, not in the special engine factory in Munich.

“The departure from a NA engine was decided quite early. Only a maximum 5% of the life time of a M3 is the engine used at full load. In the other 95% a turbocharged engine will be more efficient and at the same time give better performance”.

Thanks to the high torque this means that also the higher gears can be used (for overtaking etc).

“The boost pressure will be at a maximum 1,3bar. That way we can give the customer the same power level at high temperatures and high altitude. Under normal conditions, the boost pressure will be lower” explains Biermann.

The crankshaft is forged.

There is a separate oil return system for the turbos to ensure that the oil is evacuated even during extreme braking and cornering manoeuvres.

On cooling:
In addition to the main coolers there are several secondary coolers, both for high and low temperature circuits, as well as for the turbo and transmission.

There is also a secondary water pump to provide a balanced temperature management.

On transmissions:
The manual is derived from the 1M but has been modified and is now 12kg lighter. The 7-speed DCT is taken from the M5/M6, with it's longer ratios (over the E9x M3 DCT - helping fuel consumption).

On brakes:
Standard front brakes will be 4 piston callipers and the CF brakes will have a 6 piston calliper.

Driving impressions:
(Biermann seems to be driving quite enthusiastically during the drive)

The force of 430PS and 560Nm is delivered with a dry, throaty and bassy rumble. The “Tourenwagen-timbre” is no longer remained.

“No M engine should shy away from high RPMs”, Biermann says as the tacho needle has left 7500rpm behind a long time ago.

Biermann steps on the throttle and enjoys the "blaring sound of the valved exhaust system".

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I found this quite interesting and informative. At least until we can get final specs and drive impressions/comparison tests
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Last edited by Boss330; 11-20-2013 at 01:57 PM..
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