The epitome of racing feeling in everyday traffic starts a new round. 35 years after the debut of the first BMW M3, BMW M GmbH presents the latest generation of its high-performance automobiles in the premium mid-size segment. Time to introduce the two new vehicles. In the #M3M4explained series, the developers have the floor.
Link to the road: When Oliver thinks about innovations, it is all about the driving experience and aspects such as dynamics, comfort or precision. The BMW M developer is responsible for the chassis of the new BMW M3 and M4. In the video, he presents it - and explains important details. In addition, Oliver shares his knowledge with the M community. We publish an excerpt from the questions and answers.
BMW M ENTHUSIASTS ASK, BMW M EXPERTS ANSWER.
How much better is the chassis stiffness compared to the old generation?
Compared to the predecessor, the new generation is overall +15 % stiffer than the old one. Beyond global stiffness we also focused on local rigidity of the connections for front and rear axles.
How much was the front axle unsprung weight decreased in percent compared to previous M3?
In vehicles equipped with M Carbon ceramic brakes, with the new wider wheels of the new generation the unsprung weight increased by only 0,9 kg per side (at a total weight of roughly 55 kg).
How does adding more camber affect the handling of an M3/M4?
Compared to the predecessor, the new models run higher camber at the front to improve turn in and cornering performance. Tire development and chassis parameters such as camber and toe were perfectly matched to each other during thousands of kilometers of testing.
Why is there no use of carbon fiber for the strut bar and driveshaft like in F8X cars?
With regards to the engine bay strut bars: with the given package situation in combination with our functional requirements, using steel instead of carbon works better in the new cars. With regards to the driveshaft: Spoiler Alert! Watch out for another episode to come.
Why is the rear subframe made of steel and not aluminum?
The rear axle is a very complex construction - think of all the things around there: fuel tank, exhaust system, differential, prop-shafts, driveshaft, wide wheels, trunk space and seats. There is only very little room left for the rear axle subframe to fit in between all that. Compared to a weight optimized steel construction, an aluminum construction requires more space to achieve the same strength and rigidity - more space than was available here.
Did the extra chassis stiffening add a lot of weight?
The total mass of stiffening used is about 25 kg of weight. However, the improvement in driving dynamics makes this a well invested weight gain.
Does this car have anti-roll bars?
Yes, there are anti-roll bars at both axles.
What is the advantage between front double wishbone suspension and strut?
Most of all, it is primarily determined by the package situation of a given platform especially with front engine vehicles. Multi-link strut constructions – as used in the BMW M3 and M4 – provide excellent steering precision and wheel movement within all our functional requirements with a lower weight due to fewer parts.
Will the front camber be adjustable?
There is no camber adjustment at the front axle.
What are the main differences between G8x and F8x adaptive dampers in terms of hardware?
In principle, the new dampers are a next generation development based on the predecessor with a specific hydraulic setup.
What have you done to improve steering feedback and engagement?
There is no particular single item that addresses this point. It is the result of a meticulously fine-tuned combination of M3 and M4 specific components such as steering rack, front axle and suspension, chassis stiffening and wheel combinations.
Which setting is the best for a hillclimb with bump corners and slow corners?
I recommend starting with the Sport setting which has been optimized for Nurburgring Nordschleife (which is slightly undulated as well). If that is too stiff, switch to Comfort.
Is the suspension tuned on the assumption that only the driver's seat is occupied?
Providing a vehicle that serves as a frequently used track day car, as well as a daily driver capable of driving long distances fully loaded, is one of our major targets. Hence, the suspension setup is developed to work with all load situations – whether driver only or fully loaded cabin and trunk.
Is there a way to set the suspension to always start in a specific mode?
I recommend to individually program M1 and M2 to your personal preferences - then everything you like is just one touch of a button it needs.
Which wheel and tire option do you recommend for optimum steering feel in daily driving conditions?
The optimum sporty driving characteristics will be achieved with one of the 19"/20" wheel combinations - on a track as well as in daily use.
What is your favorite handling M car, apart from the new M3/M4?
BMW M2 CS.
What's your favorite color?
Brooklyn Grey metallic.
Which university (and discipline) did you attend?
I majored in mechanical engineering in Stuttgart.
What was your first BMW?
BMW 320d Touring (E46).
What is your favorite classic BMW? And why?
BMW 2002tii – small, lightweight, lots of power.
What car do you drive?
VW T5 California.
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