This being my first rx7 (88 turbo) I didn't really know what the stock turbo looked like. But after opening up my turbo and seeing the dual internal waste gates I'm guessing this is a S5 turbo. Though this turbo also had a interesting tag on it. Can anybody help me make sense of what this tag means or if its on all rx7 S5 turbos?

Turbo tag

 

Hitachi 18S (HT18S) is the stock S5 Turbo. The tag indicates that the turbo compressor has been upgraded to the Garret T04E. Not sure what the last bit is. This is pretty much the same as the BNR Turbo conversion.

 

I thought the same thing but it looks to me like the compressor housing is the same as stock. Are you saying that the compressor wheel was changed?

Sorry for the bad photo it's all I have right now. I'll try to get more Friday.

 

Most likely a T04E wheel trimmed for the stock housing.

The next step up is changing the compressor housing.

 

If the wheel was already trimmed for the stock housing I assume I'm going to need a new wheel if I want to upgrade the housing.

 

Yup. Check these out. This guy has excellent worksmanship.

https://bnrsupercars.wordpress.com/8...turbo-ii-fc3s/

 

its also possible to bore the stock housing out for a larger wheel, i have an H trim in a stock compressor housing

 

Sorry to be the downer, but that aftermarket tag doesn't belong to the turbo pictured.
T04E is a compressor housing size and yours has the stock HT-18 number cast in it.
That compressor housing has not been modified for an upgraded compressor. When machined for a bigger V-trim or H-trim, the wall of the inlet gets really skinny. Yours still has plenty of meat.
The tag attaches to the flat on the compressor housing and yours doesn't have any mounting holes. It still shows the stock N370 part number.
The compressor wheel is hard to identify without measuring, but if it fits in the stock compressor housing, it's a stock compressor.