Well... on the street I run 14psi with the boost controller off(540ish rwhp)..it won't be any traction on 1st and 2nd gear but 3rd gear they hold pretty decent.
1990 Nissan 300ZXTT Twin Greddy TD06L2-20G 745rwhp 593rwtq no tuning (26psi no nitrous) 7.29@108mph 1/8 mile 10.9@139mph 1/4 mile (1.75 60ft) Waiting for stronger wastegates spring