Yes I can understand the warranty issue, however when people mix housings the warranty issue is far greater than internal parts. A small turbine housing could cause catastrophic damage in a matter of minutes, and then you just return the cartridge.( I'm using "you" generic, not personal"). Your point is well taken though, the relationship you have with someone # B/W is golden and although I don't agree with the bearing thing, the fact that someone in the company is willing to discuss your ideas with you is a big plus for me, gives me a much better impression of B/W. I am a lot better talker than I am a typer, and I look at things differently than most people I Know, that said, I do agree that 98% of the time a rebuilt is the way to go, quick and easy! Mr Haney, you mentioned something that tweaked my interest, at what point did you try machining compressor covers for a bigger wheel? or was it to tighten up clearances?
Short answer from me is I don't know. Like I said before, try to find a turbo repair shop, not a truck repair shop, and ask if they will sell you the parts. Please note, if I seem a little vague, I stopped doing side work when I bought my own truck 12 years ago, I still rebuild one now and then, and have never had a problem with parts, but maybe it's because of old relationships, I don't know. Also this forum thing is somewhat new to me, so I hope I don't offend anyone. I really enjoy the information.
It's to install a larger compressor wheel. Sometimes you can actually find a cartridge made with the turbine and compressor wheel you want from the turbo manufacturer, but will not have a compressor cover with the A/R ratio or application you need...........then you modify a cover to fit your needs.
Yea, we used to do this probably 15 years ago, I've always been bad with numbers but we used an older cover with a newer, larger wheel, the newer cover did not flow for crap. at the time we were using air research turbos. We also used to machine the mating surface (cover to center), to tighten up the clearances. This was about the time we started to learn pressure did not necessarily mean flow.
You will not believe how many people think that more boost pressure equals more horsepower. It's all about how much fuel you can get in the engine and supplying the air to burn it completely. I like low boost pressure designs with high CFM.............this makes for a very efficient turbo, but this narrows the RPM range of the engine to produce peak power without significant turbo lag. You can also get too much air at low RPM and surge the turbo trying to play like this