GOT THIS FROM SCOOBY TUNER WEBSITE MATEY.
The VF series (VF22, VF23, VF24, VF29, VF30, VF34, VF39) are the most common direct replacement turbos. All VF-series turbochargers use the same roller bearing, water-cooled core assembly. The differences are in their wheels and housings to achieve different flows.
The VF22 has the largest potential for peak horsepower. In other words, in the IHI model range, the VF 22 supports the highest boost levels. It is capable of running up to 25 psi. Because it is a roller bearing turbo, turbo lag is minimal...the boost comes on around 3300 rpm. Expect to max out the VF22 somewhere in the 400-450 hp range.
The VF23 starts the middle ground. It comes on boost around 3100 rpm and is capable of running 20 psi of boost. Expect to max out the VF23 somewhere in the 300-350 hp range.
The VF 24 starts to come on around 2900 rpm and will significantly improve power through the midrange over the stock TD04 turbo. However, the VF 24 is only capable of running around 17 psi.
The VF23 and VF 24 are a great replacement for those who value drivability higher than maximum power.
The VF29 & VF30 delivers a very wide increase in torque over the standard TD-series turbos.
The VF 30 is a fairly new IHI model that utilizes the exhaust housing of a VF24 and the compressor housing sized between a VF 23 and a VF 22. It comes on boost down low (around the 3000 rpm range). With upgraded injectors, fuel pump, and engine management, the VF 30 is good for 365-390 horsepower. It is important to note that the VF30 is NOT a roller bearing turbo.
The IHI VF34 (which comes standard in the Japanese market STi version "RA") is a new roller bearing turbo. It has the same specifications (compressor size, etc.) as the VF 30. The difference lies in the roller bearing which, theoretically, allows quicker spool and better response. It costs a couple hundres more than a VF 30. The VF 34 maxes out around 365-390 hp. It is probably the most popular option for big turbos on the WRX.
Model Type Compressor Inlet Diameter Compressor Housing Nominal Turbine Housing Turbine Approx A/R Compressor Wheel Blades Turbine Wheel Blades Waste Gate Actuator Turbine Casting ID & Batch
VF22 Roller Bearing 48.5 A 9.4 PZ20-H 94001 0.71 5 11 C395 H, H4
VF 23 Roller Bearing 46.7 B 9.4 PZ20-H 94001 0.71 6 11 C395 8psi TBA
VF 24 Roller Bearing 46.7 B 9.4 PZ18-H 94001 0.63 6 11 C418 8psi H, S4, 66
VF 30 Bronze Bearing 47.9 C 9.4 PZ18-H 94001 0.63 6 11 C484 H, S4, IC F55
VF 34 Roller Bearing
