87mm Turbine vs. 96mm turbine power potential
 

So here's what I'm working with. 2002 24 valve, converting to built 215 P-pump and upgrading the turbos. The truck is currently running BD R700 twins (58 over 471). The owner of the truck is gunning for 1100 HP. It's just a toy, may see some street time but mainly just for playing. He wants to utilize the turbo plumbing he has and replace the turbos. The secondary turbo is no problem, thinking probably a 64/80 or 66/80. The problem I'm running into is the primary has a T4 flange, which limits my options. I did some research and found the S482/87/1.25 T4 turbo.
My question is, will this turbine support anywhere near the 1100 number on a p-pump 24 valve, or is the 96 mm turbine the way to go? I realize the 96 is probably better, but considering the T4 flange, it's not the easy option.
My recommendation was ditching the current setup and buying another complete kit, but he is trying to save money. I know 1100 HP isn't a "budget" build, but he wants what he wants.

P.S.- I see some shops offering custom 96 mm housings with a T4 inlet, this may also be an option.

This sounds like a customer you do not want and will not appease. IF it makes 1100hp with a t4 primary it will be low in the rpm range and be a head gasket eating parts destroyer.

I'm really just trying to get info to back up my recommendation and also make sure its the right decision. If I didn't want every customer that had unrealistic expectations until I talked them down a bit I wouldn't have any customers.
With that in mind, thoughts on the 96 mm housing with T4 flange?

You can modify a 96mm 1.32 housing to T4 pretty easily.

Yes. Several shops doing that because some orgs had t4 rules.

What diameter is the hotpipe?

Why not weld a T6 flange onto the piping and be done? Way more economical given the turbo options out there in T6 1.32 96x88 turbine flavor are more economical.

I hadn't heard of that, but I guess that makes sense. Just re-driling the flange or does it take more than that? I will have to do a little research on that.

I had thought of doing this too. Of course its a little more than that, the downpipe and support bracket would need modified too, possibly the inter stage pipe. Looking at all options. Thanks for the input.

It works best to drill and tap the housing to put a stud in it, if your plumbing can accommodate that. There's hardly enough room for a bolt head once you drill it for the T4 pattern.