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BMW brought out their M6 replacing the Z4s they raced last year. We had a look at the Z4s in GTE trim a while back too. I believe the M6 has an advantageous aerodynamic shape vs. the Z4. Picture from BMW.
The big news is under the hood. The previous BMW cars had naturally aspirated V8 engines. The new M6 GTLM car essentially has the same engine as you get in the street car which is pretty remarkable. It does have some race car changes such as the intake, exhausts, and dry sump oiling system, but that’s about it. Oh yeah, it also has air-to-air intercoolers instead of the stock air-to-water which I think may have been mandated by the rules. Picture from TopSpeed.com.
The engine is so stock, it even has the OEM Honeywell turbos on it! You can see the part number (800072-6) stamped in black on the compressor housing. I guess this makes sense as the car is rated at 560hp from the dealer and the race car is rated up to 585hp. The race car has the exhausts dumping out the sides behind the front tires as opposed to the restrictive stock downpipes that snake down behind the engine, so the extra breathing capacity probably allows the turbos to stay in their sweet spot. The turbos are still journal bearing even. Granted, the car is an M-series car which has the most demanding requirements of the turbo, but it’s still pretty amazing to me that the OEM street car turbo holds up just fine to 24 hour endurance racing. Don’t try this with more base level cars that have turbo engines for fuel economy reasons as the materials used on those more pedestrian car turbos will not handle the high heat of motorsports. The race car does plumb cooling air to the turbine housings of the turbos by way of the two shiny chimneys to help keep things cool. While the street car might spend a few seconds at a time at WOT, the race car is spending nearly all of its time at WOT, especially on the high speed banking of Daytona. Picture is a screen grab from a Racer.com video doing a walk-around of the race car.
The huge news going into this year was Ford bringing back the GT to compete at Le Mans rekindling the old rivalry with Ferrari. Contrary to their crosstown rivals at GM, Ford went with boost to make power. Picture from Bloomberg.
The 3.5L V6 Ecoboost engine is based on their Daytona Prototype engine which is based on the street engine to a degree. Picture from RK Motors Charlotte.
