DTS/DIF problem: mesh going-through?

Hi all,

I created a DIF track, it doesn't have any concave geometries nor holes on it.
I created a DTS car as well, checked its collision object and made it slightly larger than the car object itself.

When I tested the car to run on the track, if the velocity is high, then sometimes its body part gets stuck (going-through) inside the track.

In the Vehicle datablock of car.cs, I also tried this script commands:

massCenter = "0 -0.5 0";
density = 1000;

But it didn't work.

Any solution to this problem?

Thanks again,

O. Newman