We’ve written about the diesel horsepower war that’s pit Chrysler, Chevy, and Ford against each other many times in the pages of Diesel Power. This war has been very profitable for the Detroit manufacturers, as the sale of diesel trucks for all the combatants involved has gone through the roof. Each brand of truck has its own philosophy on how to make its diesel better than the competition’s. But in this battle (which has gone on for more than a decade), the differences between the 6.6L and 6.7L engines and six-speed transmissions, axles, and suspensions are relatively minor compared to the soldiers in another diesel grudge match that’s about to begin on the other side of the automotive world. Audi and Mazda are about to bump heads in LeMans prototype racing with two distinctly different diesel-powered race cars. Here’s an inside look into each camp’s battle plans.
Audi’s E-Tron Quattro hybrid system is based on a 3.7L diesel V-6, but there is also an electric motor that can drive the front wheels. The E-Tron’s motor generator unit (MGU) uses planetary gears and two electric motors to couple a flywheel (mounted next to the driver) with the car’s front wheels.
During vehicle braking, the front wheels spin the MGU. The motor generator unit creates electricity as it helps slow the vehicle down. The electricity is then sent to a second electric motor that spins a carbon-fiber flywheel in a vacuum. The carbon-fiber flywheel stores the kinetic energy from braking as potential energy in the flywheel—instead of using a battery. After a corner is taken, the system reverses the process by delivering electricity from the flywheel through the electric motors to the front tires to improve acceleration. The regulations allow approximately 100 hp for six seconds to be transferred to the front wheels, and regeneration can only take place in certain areas. The planetary gears adapt the transmission ratio during acceleration and braking. The two independently powered axles on the E-Tron Quattro are synchronized via Audi’s control strategies. Racing rules say the system can only be used during high speeds, otherwise it could provide an unfair traction advantage.
Diesel Power Saber Rattling
Racing aficionados can see right through our hypothetical Audi vs. Mazda war provoking. This is because while the two cars will likely run on the same race track simultaneously—the cars are really in two different motorsport classes. The Audi runs in LeMans Prototype 1 (LMP1), which is meant for factory teams, while the Mazda will be eligible for LeMans Prototype 2 (LMP2), which is designed for teams that use production engines. To qualify for LMP2, Mazda will sell its diesel race engines to certain teams. Also, this is kind of a David and Goliath scenario, since Mazda’s budget is much smaller than Audi’s.
Mazda has decided to use a smaller diesel engine and no hybrid system. Instead, its production-block 2.2L diesel is projected to make 400 hp and only weigh 340 pounds fully dressed. This inline four-cylinder giant killer has Garrett turbochargers, two stages of intercooling, Carrillo connecting rods, CP pistons, and a Bosch ECU.
Mazda North American
Audi Of North America