[thepieman]

Turbo Details

Maxed out at 400-450 according to the above

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.

One other turbo to note is the VF 39...it comes standard in the USDM STi. While we don't have all the specs yet, these are a new roller bearing, TWIN SCROLL design. Performance numbers are pretty similar to the VF34...maxing out just under 400 hp.

A new high performance modified IHI turbo has made its way to the market recently. They are the Power Enterprises PE 1818 and the 1820. The 1818 supposedly comes on boost extremely fast...which make it great for road racing or aggressive driving (remember to be responsible :^). The 1818 maxes out somewhere between 350-375 hp.

The 1820 is larger than the 1818 and is capable of running more boost, but at the expense of more turbo lag. Expect it not attain full boost until you have passed 4000 rpm. However, it can be tuned to 400+ hp.