CAT Turbo identification

[92 D/UNIT]

I was wondering if any one could help identify this Cat turbo and tell me if it could be a candidate as a primary in a low HP towing twin setup?
It has a about a 64mm inducer (whats the best way to measure a 7 blade wheel)and a 92mm exducer with a 110 AR exhaust housing. I think its a BW S310 variation. it has a s310g119 on the tag but I couldnt find any info on it, maybe off a CAT C9
the exhaust housing seems way too big for a single. and the turbo in general seems to be juz a bit small for towing twins.
any thoughts?

[92 D/UNIT]

I guess what im getting at is what is the minimum amount of air flow/volume required out of the primary turbo on a compound set up to make it opperate effficiantly or even opperate at all?

[92 D/UNIT]

bump

[KTA]

The low pressure turbo has to be able to supply more air than the high pressure turbo for it to work. It is possible you could run a 64mm into a 62mm, but you wouldn't get much compounding effect. Most setups rely on a low pressure turbo that can supply double the air of the high pressure. This fairly evenly splits the work between the two.