Another update & teaser..
Just got the turbo back from SoCal Porting. They gasket matched, ported and smoothed out the turbine scrolls. Afterwards, they applied Cerakote High Temperature Ceramic Coating to the turbine housing. They claim that their porting can improve spool by ~200 RPM and result in 10-20 whp up top depending on the turbo and application. Obviously, the ceramic coating will help keep the heat inside the turbine housing maximizing the exhaust gas energy. This should help further decrease spool and lower under-hood temperatures resulting in lower IATs and a denser intake charge for maximum power. This was a no-brainer for me as this build has been about injecting some modern engineering and efficiency into the "archaic" EJ257. I wanted to have the ultimate, holy grail of OEM+ turbo setups.
Porting the turbine inlet yielded a ~16% increase in the cross-sectional flow area. These aren't the most accurate measurements, but they were able to port the scrolls from ~40.4mm to 43.6mm (~2980 mm^2). For reference, the single scroll VF48's P18 turbine inlet has a non-ported cross-sectional area of ~1570 mm^2. That's ~40% less compared to ~2560 mm^2 for the non-ported P25 twin scroll housing. Also, the wastegate design is significantly better on the twin scroll P25 housing with its dual flappers (one per scroll).
A quick re-cap on the turbo setup:

Between the shadows and black coating, it was difficult to get pictures of the ported scrolls.. but I tried. I apologize for the poor image quality. It doesn't do SoCal Porting's work justice. I wish I could have gotten a picture of the porting before they ceramic coated it. The ports are very smooth!
Just got the turbo back from SoCal Porting. They gasket matched, ported and smoothed out the turbine scrolls. Afterwards, they applied Cerakote High Temperature Ceramic Coating to the turbine housing. They claim that their porting can improve spool by ~200 RPM and result in 10-20 whp up top depending on the turbo and application. Obviously, the ceramic coating will help keep the heat inside the turbine housing maximizing the exhaust gas energy. This should help further decrease spool and lower under-hood temperatures resulting in lower IATs and a denser intake charge for maximum power. This was a no-brainer for me as this build has been about injecting some modern engineering and efficiency into the "archaic" EJ257. I wanted to have the ultimate, holy grail of OEM+ turbo setups.
Porting the turbine inlet yielded a ~16% increase in the cross-sectional flow area. These aren't the most accurate measurements, but they were able to port the scrolls from ~40.4mm to 43.6mm (~2980 mm^2). For reference, the single scroll VF48's P18 turbine inlet has a non-ported cross-sectional area of ~1570 mm^2. That's ~40% less compared to ~2560 mm^2 for the non-ported P25 twin scroll housing. Also, the wastegate design is significantly better on the twin scroll P25 housing with its dual flappers (one per scroll).
A quick re-cap on the turbo setup:
- OEM JDM S208 IHI VF58 Twin Scroll Turbocharger
- Ceramic Dual Ball Bearing CHRA
- Forged Billet Aluminum 6+6 Compressor Wheel w/ Extended Tips (Reducing rotational mass while also improving strength and flow)
- OEM Titanium Aluminide (TiAl aka Gamma-Ti) 9-Blade Turbine Wheel & Shaft (Significantly reducing rotational mass while improving flow, spool, transient response)
- Lightly Ported/Polished Compressor Inlet
- Ported Turbine Housing Inlet Scrolls (~16% larger cross-sectional flow area improving spool and top-end performance)
- Cerakote Ceramic High Temperature Coating applied to the Turbine Housing (Retaining the heat, maximizing exhaust gas energy, improving spool and reducing under-hood temps & IATs)
- Forge Motorsport Billet Aluminum IWG Actuator (Improved durability and wastegate control/response along with higher boost levels)
- OEM JDM S208 Equal Length, Twin Scroll Header & Uppipe
Between the shadows and black coating, it was difficult to get pictures of the ported scrolls.. but I tried. I apologize for the poor image quality. It doesn't do SoCal Porting's work justice. I wish I could have gotten a picture of the porting before they ceramic coated it. The ports are very smooth!