Holset hx40 makes 685hp and 584tq

[LandSpeed-DSM]

So you your saying garret housings don't have bigger volutes on a t4 vs t3, all else being equal. I really don't know for sure, just going off what I have seen of them. But then again, I guess I doubt you could even get a t4 and t3 in the same a/r and same turbine.

Well, I tried to cover that better with this statement:

If they have the same A/R for the same turbine wheel (again, look at the diagram I posted in post #63) they could still be different in several dimensions. If they have a bigger nozzle area divided by a radius change that was big enough that could still produce the same A/R ratio and have vastly different flow and spool characteristics.

From what I have seen (anecdotal ofcourse) that due to how they (Garrett) end up packaging some of these turbos, there may be the odd set of T3 and T4 housings for the same unit that come close or overlap in terms of flow and have the same relative footprint, and just a different flange so they can be used on a wider range of applications.

These are rare however, and is what I think Bullseye was going for with these housings to accomodate the most diverse array of part combinations with limited space.

For the DSM crowd, who run everything from T25 to T4 and even one or two (Kevin Jewer comes to mind) using a T6 frame turbo.

By making this same size housing, and just using a different inlet flange they have left themselves open to more setups, because if you have room to fit a T3 turbo and manifold, you can likely accomodate a DSM flange turbo and manifold.

But not necessarily the other way around. This may be a stretch, but for a mass-marketed item it would at least seem to be a consideration. And as it turns out you can get full advantage of a S200-59 or HX40 Pro with this "small" turbine housing, which was probably another concern.

They have to be able to sell enough to make it worth while for them to offer these, and with this crowd in particular, they need to back it up with results to be able to sell enough.

Perhaps that logic is specious or ill-formed.. its partially due to me doing this in a hurry on my break