Ok data logs have been run.
larger 6cm smaller 4cm
Full 10 psi 3500 3185 Roughly 300 Rpm difference
Once again the runs were performed from 1800 rpm flat to the floor in 3rd gear @ 10 psi
These runs were done using a GFB atomic bleed valve so its about the slowest way to get to full boost . An electronic boost controller keeping the gate shut for longer would achieve quicker spool up for sure.
It does feel a little better up top and may even take a bit more timing advance due to the less back pressure but unfortunately im not in the position to compare tuned dyno runs back to back.
So Im happy with that for now.
Ive decided to remove some of the above acceleration information as its not accurate. Each run was done with a different diff ratio . I should have done data logs the day before I removed the 4cm , Same tune same diff ratio ect.