IndyCar’s hole in the head (floorpan)

Triangular holes in IndyCar underbody

A reader writes, Dear AR1.com, Does IndyCar have a hole in their heads? They put a hole in the floorpan to reduce underbody downforce for 2015. It is the stupidest thing I have ever seen. If they wanted to reduce underbody downforce all they had to do was add blockers in the underbody exit tunnels like CART did years ago. Worked perfectly at 1/100th the cost.

Had those idiotic holes not been there, the aero kit designers could have used that 'dead' space to reconfigure the sidepods that would have helped the aerodynamics as well as add some additional level of protection for the drivers. Signed, Curious Minds Want To Know

Air hitting the sloped inside of the Chevy Butt Bumpers lifts the rear of the car off the ground. Air then hits the large underside of the car and, like a kite in the wind, we have liftoff.

Dear Curious, We too questioned the holes in the floorpan, but yes they were worried the cars would have too much downforce and yes the tunnel blockers would have accomplished the same thing at a fraction of the cost. People look at those holes and laugh. They are not the cause of the flying Chevys however. That is caused by the design of the Chevy Butt Bumper – when the car gets backwards the air flowing into the Butt Bumper lifts the backend of the car up, and once up far enough, the air hits the large underside of the car and it takes off like a kite in the wind. Those Chevy Butt Bumpers need to be changed before race day because any Chevy getting backwards is going to take flight. Say your prayers for them. Mark C.