This model turbo is the latest bolt on upgrade for the WRX. It is standard on all STI models as of late 2001. The VF 34 has the same specs as the VF30 but features a ball bearing cartridge assembly. The VF34 will spool up approximately 250RPM quicker than the VF30, making it a good all round performer. Ball bearing turbo with a 479 comp wheel and P18 turbine housing.All IHI VF turbos are a bolt-on for Subaru EJ20, EJ22 & EJ25 engines.
The VF34 is a good comprimise and is still capable of holding boost pressures to higher RPM than the standard TD04 turbo, but will spool up quickly. It will still be slightly more laggy than the TD04 but not really all that noticeable.
The VF34 is nearly identical to the VF30, with the same exhaust housing and compressor. However the VF34 goes back to the ball bearing design, and in doing so achieves full boost approximately 500RPM sooner than the comparable VF30. The VF34 is the most recent IHI design and as such costs slightly more than its counterpart. Top end performance and maximum output are identical to the 30.