I have a BBK Full setup with a Exedy Twin Disk clutch only making around 450whp/450wtq.

I recently went Speed Density with a VTA Tial Q BOV.

Only when I apply heavy to WOT throttle and shift gears, the RPM quickly spikes and go back down. If I apply light or moderate throttle, it shifts fine.
I have checked for user error by making sure my foot wasn't on the gas. It still goes up. This happens across all gears.

3 Possibilities in my mind:

1. Compressor surge from too stiff of spring in BOV
2. Clutch Slip
3. Sticky trottle

The TD shouldn't slip at that level of power. But is there a way to test to see if it is indeed the clutch?

 

I did this trick: So I put my car in 4th going and at 30 mph and floored it, and both my RPM and car speed increased (albeit sluggishly since it is on 4th going 30mph).

So I don't think its my clutch.

 

I had a similar issue. It was able to be tuned out, although that was a long time ago when I was running my stock ECU. It was an intermittent issue when I had it.