Forgive me for being HIGHLY skeptical about what scarbs is saying. All because of 1 simple reason. No single stage axial compressor that is commercially available can even get near the kinds of compression ratios needed for this application, especially not in the changing conditions presented in F1 of constantly running at different tracks at different barometric pressures, different temperatures etc. Until somebody can either A. show me a picture clearly showing that it is an axial compressor or B. show me a design that allows such high compression ratios in these conditions, I'll continue to not believe it.
In one of the pictures I think I see what looks like the diffuser and circular pipe around the turbocharger compressor, a characteristic of centrifugal compressors.
Question to those who are savvy with the regs. Would a double sided compressor be allowed by the rules. Technically it is still only one stage of compression but simply with 2 inlets to the turbocharger compressor. If this is allowed then it would be a way to drastically downsize the size of the compressor.
Edit: I can see the possibility of a mixed flow compressor. Don't know to much about it though.