RB26 GTX Cores in factory housings best choice?

[Piggaz]

Just a general observation over the years with people going down this path. The results with guys jamming these newer style compressors into the GTR bolt on housings never quite perform as well as the results with using the original Garrett GTX housings. Could be purely coincidence though.

[TXSquirrel]

4 hours ago, sneakey pete said:

So that's just the rear. Would then still need to get a front housing machined to fit.

Yes they do front housing as well.  The R33 guy I chat with told me he just called them up and they fit front housing on the -5's for him.  I didn't ask him how much though.

4 hours ago, Piggaz said:

Just a general observation over the years with people going down this path. The results with guys jamming these newer style compressors into the GTR bolt on housings never quite perform as well as the results with using the original Garrett GTX housings. Could be purely coincidence though.

I contacted another vendor about fitting GTX on -9's, here is their response.  I don't full understand and maybe you folks can explain better.

Garrett haven’t released -9's in a GTX version, the GTX turbochargers all require surge slotting in the compressor housing due to the efficiency of the compressor wheel. As the Garrett bolt on compressor housings are quite compact, there is no room to surge slot these to retain their bolt on adaptability.
We have done a few GTX wheels into factory housings, but they are more suited for high end vehicles, as we fit 0.85a/r turbine housings to them, as opposed to the factory 0.64a/r (free up the back pressure to try to eliminate some/majority of the surging). A large blow off valve also helps eliminate this issue.