Cadillac will send its quartet of DPi-V.Rs into the 2018 IMSA WeatherTech SportsCar Championship season with a downsized engine. 

In 2017 Cadillac used a naturally-aspirated 6.2-liter V8 and smashed the field with a 70 percent win record, taking both the manufacturer's and driver's championship courtesy of Wayne Taylor Racing. This year, the brand will chase another championship using a downsized 5.5-liter V8.

According to Racer, the engine will lose 700cc of capacity from each combustion chamber through a reduction in stroke which will rob them of some power, but mostly torque, which was the main reason no one could touch the DPi-V.R last year.

Allegedly, the motor makes 580-horsepower at 7,050 rpm, which is approximately the same as other DPis from Acura, Mazda, and Nissan. Nothing else about the engine will change, it will continue to be built by Earnhardt Childress Racing and retain its self-contained dry sump lubrication system, dynamic pressure air intake, and most importantly the top exit long-tube exhaust headers which are the source of its intoxicating sound.

Hopefully, the changes will stave off the serial BoP restriction the DPi-V.R was subject to last year, which led to an increasingly difficult car to drive thanks to fixed gear ratios and a severe reduction in downforce.

This weekend's Roar Before the 24 in Daytona will be the first time both Cadillac and IMSA have a chance to evaluate the new motors on track among the competition ahead of the Rolex 24 later this month.