I am hoping some of you more seasoned turbo guys can help me decide on a turbine housing.
I currently have a GT35R with a .63 A/R ATP "ultimate" internal waste gate setup mounted to a ported stock turbo manifold. This is going on a Rebello built 3.0L L6 with 8.5:1 forged internals, ported head and a custom cam. Details are in my project page.
I recently purchased a custom made, divided t4 manifold with an external wastegate. I originally planned on buying a bolt-on t4>t3 ebay adapter, BUT....while I'm at it (been here before?), I might as well look into other options that might have performance advantages. This is where you come in .
Here are the "best" options available from ATP I have come up with so far:
1) Keep my current housing and buy a block-off plate with a 3" v-band outlet.
2) Switch to a divided t3, .78 A/R turbine housing and weld or bolt on a divided t4>t3 adapter
3) Switch to a divided 1.06 A/R t4 turbine housing.
Here are some considerations:
1) This will be a street and occasional track day car
2) I don't want to keep the boost threshold at a reasonable level, i.e. full boost by 4K
3) I'm not looking for the L6 HP record but I'd like a street worthy 400+ HP machine.
I am open to other ideas and vendors. I only looked at ATP because that is who I purchased my turbo from and I know their housings will work with their turbos.