Winterbottom's car trashed by steel drain grate.

Orrcon Racing's Mark Winterbottom was forced to sit out the second and third V8 Supercar races at Shanghai today [Sunday] after a bizarre incident in the opening race.

As Winterbottom exited turn 5 yesterday [Saturday] on lap 11, he hit a steel drain grate at 130km/h, which sliced through the front Kevlar splitter and impacted on the radiator and the engine sump.

The most frightening part for Winterbottom and the Larkham-Orrcon team is the fact that as the car travelled across the upturned grate it cut through the floor tray impacting with the bottom and rear of the driver's seat before gauging a hole immediately behind the seat. This gouge measures a massive 200 x 800mm and almost sliced through Winterbottom's carbon fibre seat.

Such was the ferocity of the great that is has also sliced the roll bar cross member in half like a carbon tipped saw.

"Exiting turn five I took the normal racing line that runs right to the edge of the track and hit a drain grate that was sticking up. It made a huge thud inside the car but I didn't feel the brunt of the impact as it lifted my car of the ground," said Winterbottom.

"I knew it had done a fair bit of damage but it wasn't we got the car back to the garage that I had a look in the back of the car and seen how much damage was done inside the car.

"The grate impacted on my seat, but only just, it wasn't until I woke up this morning that it hit me and I realised how lucky I really was to escape uninjured."

The damage repair bill is expected to reach in excess of $75,000.

"I have never seen anything like this in my life - the bizarre irony this being potentially, the world's most impressive racing facility and having something as insignificant as a piece of drainage caused so much carnage to a race car. Mark is a very lucky man," added team owner Mark Larkham.

Event organisers meanwhile increased the safety overnight on the area of the circuit where the incident took place by covering the drain grates with a row of tyre barriers on the edge of the circuit and have also indicated that the drains may be filled with concrete for future events.