Taken from another thread that I am talking about the same thing:
Originally Posted by Have Blue
The cupseal was going to be the next part of the valvetrain I was going to look at - I machined slots in a CCI cupseal a while back in an attempt to improve flow around the cup edge, and I think I sent it off to someone to test. Either that, or it may actually be in my own Phantom yet and I've forgotten about it.
I did experiment with volume reducers in the valve chamber long ago, but they wound up impeding flow rather than reducing wasted space. I've got ideas on fixing that, but like everything else, I just need time.
One thing that I'm curious about is using the old style long CCI powertubes with the open faced TPC - will the extra length (and minimally reduced volume) improve efficiency, or is the slight expansion through the TPC beneficial? Perhaps the lower reciprocating mass of the newer, shorter powertube helps improve efficiency? Could the Trracer stub 'valve stem' and hammer with integrated powertube be the ultimate in Nelson valvetrains?
I'm going to quote that and post it in the thread I jsut started but I'll answer it here to. Double check with him but I believe Splattttttt found that the longer power tubes provide better efficiency. I've heard though that Trraccers were very efficient.
The devolumizers that RTR developed work really well. at one point I compaired mty Phantom to my Gargoyle with the exact same setups the only difference being the valve insert. If we are going to lower the operating pressure though devolumizing might not be what we want to do.
I think simply cutting the brass cup down so that the lip around the outside was level with the seal would be a cheap minor improvement but not the end solution