Plz help i have applied the jcar script from unity but my car accelerates very fast after every animation help....
Try to lower Torque property of the car.
Also useful (but not directly related to question), is add the following line the JCar.cs:
go.transform.rotation = transform.rotation;
Should be after `go.transform.position = wheel.position`, guess somewhere close to line 178 in function `SetWheelParams(...)`. This makes the car behaves correctly if you place it at different rotation that the default rotation in the level.