I have this t04(e)? the center cartridge has the number 409770-5019 on it and so far I've found that its probably a t04b25 with compressor side .60a/r. Basically tuner is saying the compressor wheel is about the same as the stock turbo and I was trying to figure out if you can just upgrade the compressor side to a bigger size. I can get some pictures but the turbo is on the car so it would just be installed pics.

Engine is a tii half-bridge also with alot of other mods. Turbo stops around 10psi.

 

Yes you can up-grade it, but you need to buy a backing plate, matching compressor housing AND the compressor wheel and then should get it re-balanced. Both the backing plate and compressor housing could be re-used and just machined, but after paying the machinist you'll kick yourself in the *** for not just buying a better compressor housing (get a T04S compressor housing with its .7 A/R, 4" inlet and 2.5" disscharge) which will flow more for roughly the same price.

~Mike.............