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"  Update: After this story was posted, BMW announced improvements to the 4.4-liter V-8 (including the company&amp;#039;s Valvetronic variable-lift intake valve system) that increased output by 45 hp to a total of 445 in regular trim. So Cadillac doesn&amp;#039;t get bragging rights anymore, but it still has a heck of an engine. In boxing, they call it punching above your weight. The new twin-turbo 3.6-liter V-6 in the 2014 Cadillac CTS is 37 pounds lighter than the BMW twin-turbo 4.4-liter V-8 that GM engineers set as a benchmark. And despite two fewer cylinders, the V-6 makes more power (420 hp) than the German motor. The results came through reengineering 90 percent of the parts from the current 3.6-liter, including new designs for the block and heads, and adding a pair of turbos that kick out 12 psi of boost. It also fits under the hood of the XTS in a transverse layout with minimal modification (although output drops to 410 hp). These are three key innovations on the new mill. 1. By mounting the water-to-air intercooler on top of the engine instead of at the front of the car, engineers reduced the air volume between the turbo and intake by 60 percent. This results in cooler intake air, better throttle response, and less turbo lag. 2. The high pressure from the turbo boost allows for a head design with more intake tumble, or \u00ADturbulence, which helps the fuel and air mix for better combustion. 3. With exhaust gas temperatures as high as 900 C, the turbos get hot. Extra oil passages routed from the block help keep the bearings cool, and heat shields prevent parts such as the starter from wilting. "^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.popularmechanics.com/cars/a9171/the-tech-tricks-of-cadillacs-beastly-twin-turbo-v-6-15672260/>