NOTE: Information for reference purpose only (No responsibility is accepted for incorrect data)



The “VF” series of turbo’s all have straight inlet paths, so when fitting to early Legacy/Liberty and WRX’s they need major changes to the compressor housing to take the elbow inlet. OR a modified inlet manifold is required.

All VF series turbo’s are manufactured by IHI, Japan.

Typically all Sti models come with a IHI turbo, and All WRX’s come with a Mitsubishi turbo.

WRX’s Ver 1,2,3 all came with TD05 turbo’s with a 90 degree elbow inlet, whilst the later Version 4 and 5 came with a TD04 that had a straight inlet path and was slightly smaller for better bottom end performance and less lag.

All VF turbo’s and older units have built in waste gates.


Exhaust fitting and design.

All VF series turbo’s feature the same bolt pattern and exhaust joints, so swapping them is relatively easy.

The critical part is the design of the splitter for the exhaust collector. As the VF turbo’s have a different depth to them when compared to the factory TD04 and TD05. Meaning if you swap turbo’s you should adjust the length of the splitter.

A Splitter made for a VF turbo will be too long for a TD04/05 (the exhaust simply wont bolt up) and a splitter made for a TD04/5 will be too short for a VF and hence allow gasses to mix too early causing an increase in lag and less power.


General.

All of these above turbo’s have a 60mm Outside Diameter inlet to suit the OE inlet pipe.

Size of Turbo should be also considered for gas flow. With high output engines and or large capacities, the physical size of the waste gate (hole) will be a restriction when added to the turbine (hole).
This is like fitting a big engine with a small restrictive exhaust.

Hence the need (in some cases) for remote waste gates.
A remote waste gate will flow more, because it is larger, and effectively give better boost control.
The downside is they are awkward to fit and difficult to tune with the OE ECU.