NASCAR has revealed the technical changes that it hopes will eliminate the tandem drafting that dominated restrictor plate races in 2011.
The trend for cars to hook up in pairs started in the non-championship races ahead of the Daytona 500 in February, as advances in engine cooling meant that drivers could run close together without overheating their engines.
NASCAR carried out several tests at Daytona and Talladega in October and November, and it has mandated much smaller radiators and a change in the position of the air intake on the front of the car to reduce the effectiveness of tandem drafting.
Radiator sizes will be reduced significantly from five gallons to two, and the air intakes will be moved up into the bumper fascia area, so that drivers cannot get cool air into their engines while tucked up behind another car.
The restrictor plates used on the engines will be increased by 1/64 of an inch compared to 2011, and cars will have to run softer springs and a smaller rear spoiler to make them more challenging to drive in the corners.
"We had some productive tests at Talladega and Daytona in October and November and this rules package is a result of the information we were able to gather from those tests," said Sprint Cup Series director John Darby. "Our goal was to put together a good, solid baseline aerodynamic package for the Preseason Thunder test at Daytona and we believe we've made a lot of progress in doing that.
"We want to be able to give the teams more options when it comes to drafting and we want to be able to reduce the difference in the speeds between the tandem style of racing and more of the pack style of racing that the fans are accustomed to seeing. We believe we're headed in the right direction with that."