It is now .48 so it will spool up faster, between 2500rpm to 3000rpm. I have the 12:1 ratio disc on my vortex fmu. Do I need to change it into a smaller disc like Hanh has? (6:1) I have not got it back together yet. I am tired of waiting to spool up at 4000rpm. Should I just leave the fmu like that? Any suggestion??? Btw, i have the star stage II, thanks for any help...

The fmu is boost dependent, so changing the turbine housing will not affect your fmu. Do not change it to 6:1 unless you change your injectors.

how much did it cost to change your housing

It cost me about 200 dollars thats everything. I have it changed cuz' I missed up the original housing (broke the bolt, try to fix it, end up cracking the housing). The mechanics told me that if I want it to spool up faster just get the smaller housing, so I did. I don't know if its going to affect my fuel when it is boosting. I'm afraid its going to be rich or what. Anybody else tried this? Thanks for any help...

Shouldn't really make it run rich.If anything,It would be slightly leaner on lower RPM's cause you got that extra air in there at an earlier stage.I would keep the same fmu disk.Who'd you get the new housing from and what part number?Did you loose any top end power?

Let me say it a little clearer. It doesn't matter if you reach 20psi of boost at 500 rpms, your vortech unit will raise the fuel pressure to 293psi (53 + 20*12) with a 12:1 disk. I wouldn't recommend boosting to 20psi on a stock fuel system and you're not going to get taht at 500rpms, but the point stands. The fmu will work regardless of what point you reach what amount of boost at. It works based on a vacuum signal that is attached to the intake manifold. If your manifold pressure is 10psi, it provides fuel for 10psi. It is not rpm dependent whatsoever. Leave your 12:1 disk, boost at a sane level and you will have no problems.