I just watched the video of your car.
Check the weight distribution of your car, try and achieve a 48/50 front to back.
Also your car is running some serious Anti-ackermann. If its possible for you to do (rules etc), look again at your steering angles and adjust to true or slight pro-Ackermann.
You car also runs a large KPI (by the looks of it. If you are not able to obtain spindles with a smaller KPI (with center point steering too) then try as has already been suggested, more caster angle. This will increase your front wheel contact patches in the turns.
I can't believe no one has suggested to run stiffer front rebound damping, I have a theory about rebound damping, it goes a little something like this.
Rebound damping is basically like using an anti-roll bar on turn in, on the inside wheel only. In other words rebound damping is used to slow down weight transfer on the axle in question. So stiffening the front rebound damping generally will do these things:
1.) It will slow lateral weight transfer on initial turn in
2.) It will slow weight transfer to the rear under acceleration
Because of these two things, it has the potential to create oversteer on transition, and turn in because the rear axle will transfer weight faster than the front. It will also prevent weight from shifting rearward under acceleration thus allowing greater rear slip angle.
Now that is some serious understeer as well..
