Okay, So I stumbled on a set of GT2554r turbos a while back, and I've been looking at them, and noticed the exhaust flange looked larger than a t25. They have .64 AR T3 housing's on them...so....what exactly does this do? my thinking is that it will just shift the amount of exhaust required to spool the turbo(bigger housing means it needs more exhaust than originally?)...am I close?

 

Uh with a 5.0 you want a set of bigger turbines anyways. GT25s are TINY. That being said these are not exactly big turbos and at max I would run them for 450hp. If that. Twins on a 4 or 6er would actually be pretty interesting, for a 5.0 not as much so. Keep looking JMO.

http://www.atpturbo.com/root/maps/gt25r.htm

 

If you look at the diagram straight from the turbo bible for a 5.0 at 10psi(i dont intend to go any higher, this is my DD) it is 42 lb/min, cut that in half is 21, 21 lb/min at 1.68 pressure ratio is around 70% efficient, which is the 2nd best for this turbo, if you drop to 5500 rpms, its around 38lbs, or 19 for each turbo, which falls into peak efficiency... 5000 rpm is about 17 per turbo, and so on....I shift at like 5600 now. The package size is perfect for what I wanted(a rear mount) and the smaller size means my car will spool them faster even with the loss of the energy from the exhaust cooling down so much. I figured these were just about perfect for this idea, or am I way off on something?

I like the map straight from garrett, I can't see a lot of difference, but the one from garrett is prettier