I was plotting a map for a GT3071R and I was quite surprised that its fits well.
The .63 A/R turbine will flow 425hp out of a 1.6ltr 4 cyl.
The avg. psi of 17psi will produce 280crank hp @ 12 AFR
@ 11.5 AFR it only needs 15.7psi to produce the same.
If I crank it up, add some meth+higher oct gas I can squeeze out
380chp - 11.5 AFR - 6500rpm - 26.5psi
420chp - 10.5 AFR - 7000rpm - 27psi
But these are less efficient and require a ton of fuel. But the turbo has room to grow, while spooling quickly.
If i need more top end ( unlikely, then i can up the A/R of the turbine housing.
This will spool later( 300-500rpm) but peak higher ( extra 25 hp ) at a better efficiency.
I like the garrett because its rebuildable, with interchangeable parts.
Not to mention reliable compressor maps. So i know what im getting, not just trying to copy someones build and make the same or better ( worse ) numbers. I like happy engines with fat tq bands.
So I can say I do have a "450-500hp" turbo that "can" flow up to 30psi.
But Ill be running it conservatively ( without any lag once-so-ever ) at 17psi.
This will keep the ecu happy ( boost cut at 18psi ) and me happy ( + 90 crank hp)
Engine block is well within it designed limitations ( 500chp) and rotating assembly ( 300whp)
Clutch will need to be uprated.
Ext. WG must be used with the 60mm turbine wheel ( 56.5mm in.WG T25 model is also available )
Comp. Housing: 756021-1 : 2.75"(68.75mm)IN : 2.0"(50mm)OUT
Chra: GT3071R : 700177-23 ( 60mm ) ( inwg-700177-3)
Comp. Whl: 53.1mm indu 71mm exdu 56T
Turbine whl: 60mm 84T
Turbine housing : T3 0.63 A/R : 740909-9+
About $1500 ish
View my fuel log 2015 Micra S manual: 7.7 L/100 km ... 36.8 mpg (Imp) ... 13.0 km/L ... 30.6 mpg (US) ...