I have a 1979 RX7 with a 12a turbo running megasquirt. I have 3 factory turbos. ht18-bm and ht18s-bm. Love having peak torque at 3700 rpm but looking for more. Ht18 compressor is 63 mm where the ht18s is 56mm. Is swapping to the big compressor while retaining the smaller turbine a viable option?
Running the HT18S, I made 148 rwhp @ 7200 and 149 trq. My datalog did not record on the last run, but it started losing boost at 5500 rpm on the other pulls. 4000rpms I had 7.5 psi and fininshed around 5 psi at 7800. Not sure if this was a waste gate bleeding boost or the compressor being so small. Pinching the waste gate hose had no effect which tells me the turbo is doing all it can.
I can not find anything on these turbos (a/r ratio, pressure ratio, airflow).

 

I'm not really sure this is a megasquirt question. This is more of a generic 12a/turbo question.

 

No reply as of yet on the single turbo forum. Was hoping for some knowledge hear as many ms users also play with turbos.