What's the ar ratio for the IHI?

I read all the time about the .48 and .63 exhaust housings on the T3, but someone asked me what the ar ratio was on the IHI today and I didn't know. Does anyone here? It has a 52 stamped on it, is that the ar ratio? Thanks

I have never seen the answer and 10 minutes with Google didn't get it either. I think the "52" as in RHB52 is the family code, like T3 or T4
http://www.turbo-product.com/IHI/RHB52.ASP

I searched google too. I found a page that listed LOTS of info about a whole bunch of turbos. The list was categorized and built with columns. One of the columns was exhaust ar ratio, and this column was blank next to the IHI RHB52 turbo for the 87-88 tbirds. It did have a snippet about the use of a different compressor wheel specific to the 87-88 tbirds for higher flow. Here's the page in case anyone else is interested in the read...
http://www.dune-buggy.com/turbo/turbo.htm

Some time ago, and I don't remember what year, there was a thread about one or more guys trying to gather IHI info in terms of modifying or upgrading them with parts from other IHI turbos, like upgrading T3s to T3/T4s. This was over at TF.