Does anyone else have problems with run time?
If there is someone that is running the same car as you ask them what they are geared.
As stated above it is going to be hard for someone on here to tell you where to gear for a track they don't know.
Also, Is your car free, no binding, are the bearings in good condition?
There really are alot of things that play into dumping.
But with a 12turn and 3300's you really shouldn't even be close, so my guess is take a few teeth off on the pinion gear and see how that works.