thats the thing, i think 80% is way too low for our motors. exspecially when you add a cam and heads.

 

I see what you were doing... Your engine doesn't have to consume X amount of air at Y pressure ratio. It's going to consume whatever volume it can, given displacement and RPM. Where your path takes you on a compressor map is up to what turbo you choose. The way you were plotting mass vs pressure is the ideal way an engine/turbo combo should operate, but it will never be ideal. The closest you can get to ideal is what turbo diesels run in stock form. A gas engine will never operate in the same turbo efficiency range as a diesel of the same displacement, though.

Sorry, sort of went off on a tangent there, but I hope it helps

 

So tc66's then? Lol.

Like I said though. My thing now is turbine side. It seems like a 65mm wheel with .68 housing would do good. I had a 65mm wheel on my old turbo with a .96 housing. It spool so fast it was violent but dead by 5500 rpm. So with a 3200 stall a pair of 65 turbines with .68 or . 82 should spool quick.