I've got the July '04 CAPS (The program to look up PN#'s) and did a little poking around... Here's what I found...

MR: MD613524
GSR: MD613521 (Build dates: 1Dec02-3Jul04)
GSR: MD613524 (Build dates: 1Aug04-Pres)

This raises questions for me.. Is CAPS wrong? Do '04 EVO's built on or after the above mentioned build date have the improved 10.5cm^2 exhaust housing? Also note that the RS lists the same part numbers for the build dates of the GSR.

 

Perhaps it should also be noted that both the MR and all build dates of RS's and GSR's use the same O2 housing.

 

I think that it might be possible that the Evo's built from 1Aug04 may be considered 05's hence the different housing. I may be wrong, but that would put the first 05's here around late sept early nov.

 

The 'MR' turbine housing isn't cheap! $510.68 through www.mitsubishiparts.net. The OEM housing is even more!

I think you're probably right about the model:build dates. At least it seems possible.

 

If your referring to the 10.5 turbine housing, there's a difference between the 04/05 (MR and GSR) and the earlier 10.5 housing..

I'm trying to make sense of the numbers now.. but the new 10.5 turbine housing has a revised wastegate flapper and may require a different O2 housing (you can look that up to clarify it if possible) The older turbine housing for both the 9.8 and 10.5 should share the same O2 housing.

What I was told is the new cars (Build date Aug 04 would probably be sold as an 05) got the newer revised housing and therefore explains the difference.

 

Jack,

I am aware there is a difference between the 'older' 10.5 and the newer revised 'MR' housing. I was more surprised the fact that the build dates of what I know know to be '05 models (GSR) also has the same housing as the MR.

As I previously stated the 02 housings are the same between the GSR/MR.

 

MalibuJack,

Any idea if the '05 10.5 o2 housing will work with '03,'04 designed down pipes?

 

CAPS lists the O2 housings as the same part number for all EVO's '03-'05 regardless of trim level.

 

There you go.. The main difference in the housings (besides nozzle size) would be the wastegate flapper.. if the O2 housings (according to caps) are the same, then this is also a nice possibility for a swap.. assuming it wasn't so damn expensive.

 

Oh, and if the part #'s are listed differently for the 03-04 GSR models, and the late 04-05 model, its likely that their listing the 9.8 housing vs the 10.5 housing to be offered in the new cars.

The Evo VI and V had the 10.5 housing, the VII had the 9.8 But in Japan you had several different trim levels that varied the turbo housing, and the availability of the Ti turbo..

For instance, I got (From Tiawan) a TD05HRA-16G6-9.8t turbo, this was (documented as) the turbo from a Evo VII RS2 where some of the earlier RS and RS2's would have gotten the 10.5 housing.. I think, I'm going from memory now.. My brain stopped following it after my research stopped on the turbo I got..