Id go with the GT2252, more efficient, bogger inlet, smaller outlet( but still open enough to be efficient )
Lots of lag tho, but thats the engine, not the turbo.
The small displacement and low tq numbers means youll reach 0psi just after 3500rpm or so
But this is a good thing. Our car dont dump in fuel untill then anyways.
3500-6500 will rise very quickly to whatever boost limit is set. 5psi seems to be the safe number tho.
Starting with a N/A engine which runs in vacuum, means that while the turbo is only producing 0psi
There is vacuum that has been countered already.
This means that instead of sucking air into the engine, its being pushed in.
Again this is safe.
When the fueling increases and the max tq is reached the turbo will begin creating positive pressure.
Atomspheric pressure is 14.3psi where I am.
Lets say this engine runs a 7 psi vacuum.
The engine has less pressure then the atmosphere.
So 0 psi on a gauge is really the turbo adding 7 psi of boost to compensate the vacuum.
When the gauge shows 5 psi, its actually more like 12psi vs the N/a mode ( assuming the vacuum is 7psi )
I would say that if you didnt want a standalone ecu then a proper water injection system and adjustable fuel pressure regulator would help. But this means you need gauges so YOU, and spot something wrong, and not the computer.
As long as the fuel is good, and exhaust temps are good, your not leaning out, then with in reason, the stock ecu should be able to handle the turbo. There is about 20% more room in the maf, i havent a clue about the injectors tho.
But the engine is allowed up to 5% methanol, so maybe some methyl hydrate in the water injection would help this.
Basically your physically tuning it instead of messing with the brains.
But that means the wmi must be properly tuned for progressive spray.
So Its kinda like adding stuff so you can turn up the fuelimg like you would with a mechanical injector pump.
Only, kinda electronic.
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) ...