Turbine housing: 0.83 V-band vs. 1.01 T4 twin scroll?

[ProjectS130]

Ok, so some background first:

I'm building an RB25 to drop into my '82 280ZX (or more accurately, machine shop is building it). My goals aren't too lofty; I'd like a really quick street car that I can push hard when I want to, and not worry too much about blowing up. Looking for max 500WHP, good response, full boost by ~4k RPM and strong all the way to ~7500RPM. To this end I've got the machine shop building it with forged pistons/rods/etc. Parts list:

• CP 9:1 86.5mm pistons, Manley rods
• Kelford 262/262 cams and KVS25R spring kit
• AEM 340lph pump
• ID 1050x injectors
• Plazmaman upper plenum
• LS1 coil conversion
• EMU Black standalone
• E85

Left out some stuff I'm sure but that's the gist of it. I'm pretty set on a Garrett G30-770, seems to suit my goals pretty well without having to turn the boost up too high. Along with a solid tune on E85 it should be no problem to hit 500 at the wheels from what I've read.

My question is, would I be better off with an 0.83 turbine housing with a T3 or V-band flange, or a 1.01 T4 twin scroll? If I'm chasing good mid-range power and full boost by at least 4k, without having it choke up top? I'm looking to buy a 6Boost manifold and want to make sure I get this right on the first try D=

I've read through the RB25 turbo upgrade thread (not every bit of the 61 pages but, mostly...) and still can't get a good idea of the answer here. A twin scroll housing helps with spool time, but does it help enough to (mostly) offset the lag introduced by going from an .83 to a 1.01 A/R?

Thanks =D

[r32-25t]

The twin scroll makes a huge difference and the advantage of using a t4 manifold is that it’s so universal that it gives you almost limitless options when you decide to go bigger again 

[ProjectS130]

On 3/10/2022 at 12:17 AM, r32-25t said:

The twin scroll makes a huge difference and the advantage of using a t4 manifold is that it’s so universal that it gives you almost limitless options when you decide to go bigger again 

Thanks, that was kind of the way I was leaning but was concerned a 1.01 or 1.06 A/R would move the boost threshold too far to the right on a build like this.