[twiceblown]

i was looking at the differences in pressures prior to and following the turbine. If you take a look at the differential pressure, the stock exhaust shows a difference of 31psi between the header and the O2 housing (across the turbine), and the 3" exhaust shows a difference of 28psi at 7K RPM. Now, that is 31 and 28PSI pushing AGAINST the wastegate flapper! Can someone tell me how the wastegate flapper does not open at pressure differences like this if the wastegate actuator is set to 6# or slightly more depending upon # of washers or preload (perhaps mechanical advantage of the actuator- flapper size vs. diaphragm size?)?

Also, FWombat, do you have data for the 3K and below range? I'm curious to see how much variation occurs in the lower RPMs that leads to such a decrease in boost threshold or increase spool with the 3" exhaust (we've all felt the changes). Currently, at 4K, stock pressure drop across the turbine is 11.5psi and the 3" is 11.25psi. So, from those #s, i wouldn't think that any turbo that would spool at 4K or below would see any difference in boost threshold (though the practicality of this obviously is different). Am i missing something?

Damon