BNR turbos at altitude

[Rich990]

Hello.

I wanted to find out if anyone is running a BNR at altitude and if so how it holds boost, particularly after 5000 rpm, and also what maf flow you guys see.

I have a bnr stage 2 and it just drops boost after 5000, I have an option to retrofit a 2871 or 2876 wheel at a low cost, I just wonder if it will make a difference at my altitude.

Ill start:
5500 feet above sea level, baro pressure is about 12.2 psi
BNR stage 2
Full bolt ons except manifolds
3port running 100% wgdc from 5000-redline
Fmic

Hits 20/21 psi at 3000 and holds 20 to about 4500 and trails to max 16 psi at redline
Max flow I have seen is 318 gs and hits 2.5 load and tapers off to 1.8 load at redline.

Thanks.

Rich.

[Lex]

S3 has a much larger compressor wheel and you will be able to hold above 20psi. As for flow you will be around 20-25 g/s below what people see at sea level.

[Rich990]

excellent, thank you Lex, thats what I wanted to hear!!

[Rich990]

Sorry to revive this, do you guys think a 2876 wheel will be too big for the housing and / or the turbine wheel?

5500 ft means I lose about 3/4 psi capability on the top end and I would like to be able to hold 22 psi at redline, without the turbo spitting fire.

Thanks

[aaronc7]

2876 in a small turbine housing will be a bit of an odd turbo- I would opt for the 71mm compressor option, basically making it like a BNR S3