Replacement CHRAs on R2S turbo system

[Diesel Spectre]

Hey all,
So I have a major exhaust leak that I believe is the manifold. It’s coming into the cabin and sucks. My X5 has 215k miles on it so while I’m in there I’ll be freshening up everything I touch. I’m in NJ so all emissions equipment must stay. I can’t source new turbos because even though they say they’re “in stock” no one can offer an ETA. I’ve decided to move forward with replacement CHRAs and reuse my existing housings. This isn’t commonly done here but in the VW/Audi world, it’s done all the time. If you’ve done this, please offer any pointers as it’s been 10 years since I’ve rebuilt a turbo. Both high pressure and low pressure CHRAs (with billet wheels) are less than $400 for both.
My only hang up is the low pressure EGR system. As you’re all aware, the X5 has both HP EGR and LP EGR systems while the 335 and 535ds have only a high pressure EGR system. Because of the nature of LP EGR systems, they could potentially feed water droplets and other liquid “materials” into the compressor wheel of the turbo. This is not good for aluminum wheels. For those of you who are familiar with this, is the forged billet wheel strong enough for our application? If not, my options are to remove the LP EGR system and find software that can differentiate between HP & LP EGRs, or try to source a nickel compressor wheel.
What say the educated masses?

[ard]

Far from an educated mass... You DID get 215k out of them. What is the stock wheel?



Given the temps that the turbos operate at, I dont expect water will be around very long. Even at start up and shut down, doesnt seem to be an issue.


Id prolly have a rebuild shop do this, because I dont have the experience and dont want to revisit it....


GL

[Diesel Spectre]

Yeah, I think I’ll be OK with the billet wheel. I swear I remember reading somewhere that our compressor wheel was made of (or alloyed with) nickel for this very reason. I can’t for the life of me find any info now though… ugh…
Does anyone know what the factory OE compressor wheel is made out of?
Has anyone used a billet compressor wheel and had no issues?

As far as sending it out, it’s my daily so being off the road for more than a week is problematic at best. No one has housings available to hot swap either. The chra is the part that’s balanced so in not scared to swap on my housings and go. Over a decade ago I rebuilt a few VW/audi turbos and to my knowledge they’re still running. I’d prefer to get a fully balanced chra so I know I’m good.

[josiahg52]

I thought it was the opposite, the X5s have only a HP EGR. The others have both LP and HP.

[Diesel Spectre]

Not according to real OEM. I’m not well versed in what others came with but I do know the x5 has a lower incidence of cbu than the other Ds of the same time period. I thought the heavier reliance on hp egr was a contributor to this.