2011 BMW M3 CRT Sedan

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The BMW M3 CRT also represents the worldwide debut of a new production process for carbon-fiber reinforced plastic (CFRP) components in the automotive industry. This process allows CFRP to be introduced widely in the construction of the high-performance BMW M3 Sedan-based sports car created by the BMW M GmbH factory. And that helps it achieve a weight-to-power ratio of 3.5 kilograms per horsepower (7.7 lbs/hp). A V8 engine with customary M high-revving characteristics and maximum output of 450 hp accelerates the BMW M3 CRT from 0 to 60 mph in just 4.3 seconds. The BMW M3 CRT will be produced by the BMW M GmbH factory in a limited run of 67 units. Due to the very limited worldwide volume, the BMW M3 CRT will not be homologated for sale in the USA.

Following in the tire tracks of the BMW M3 GTS - of which 135 examples were produced - this is the second small-series, high-performance M3 off-shoot to be bred for the race track but registered for the road. The exclusive character of the Sedan is emphasized by special lightweight design components manufactured as part of an innovative production process.

Lightweight CFRP Components

The hood of the BMW M3 CRT and the bucket seats for the driver and front passenger are made from a cellular carbon honeycomb, which is produced in a globally unique process pioneered for the manufacture of body components for the BMW i3 and BMW i8 models.

These new models - due to enter volume production in 2013 and equipped with innovative electric and BMW ActiveHybrid drive system technology - will feature a body consisting entirely of CFRP in the passenger cell area. In a new development, the production process introduced for this purpose enables the cuttings left behind in the construction of the body to be reprocessed. The basic material (made up of carbon fiber thread) can now be woven into CFRP mats of any size before being impregnated with synthetic resin and hardened in a similar way to the material used in the body of the BMW i3 and BMW i8. For the BMW M3 CRT this allows the creation of a hood made from two CFRP moldings encasing an aramid honeycomb structure. This construction imbues the hood with the strength of a conventional steel equivalent, but at roughly a quarter of its weight. The weight saving over the aluminum hood of the standard BMW M3 Sedan is around 50 percent.

The material produced through this innovative manufacturing technology is also used for the car's bucket seats. Here, the CFRP layers are wrapped around a recycled-paper honeycomb, with a carbon layer made using conventional production technology added to visible areas. CFRP is also used to make both the rear spoiler of the BMW M3 CRT and an air-channeling element integrated into its front fascia.

This innovative manufacturing process opens up considerable potential for increased use of CFRP in series-produced cars as a means of lowering weight. The BMW Group is leading the way in this area of automotive construction, while BMW M GmbH can call on extensive racing expertise when it comes to intelligent lightweight design. The BMW M3 CRT is the latest in a fine tradition of highly exclusive high-performance sports cars optimized with the help of lightweight design. This lineage stretches back to the BMW 3.0 CSL of the 1970s and reached another high point in 2002 with the BMW M3 CSL. BMW M GmbH also broke new ground with the use of CFRP in series-produced vehicles; like the BMW M6 produced up to 2010, the current BMW M3 Coupe comes as standard with a roof made from carbon-fiber reinforced plastic.

BMW M3 CRT Sedan: Review (2/2)