Drift Tengoku — September 2004 · Page 36

The next requirement is a turbo swap. The factory twin turbos on the JZX90 and JZZ30 reach roughly 380 PS at 1.2 kg/cm² boost, while the JZX100's single turbo tops out around 320 PS at 1.0 kg/cm². Auto Service Mori recommends the actuator controlled GT2835 Pro, which replaces the original turbo.

At under ¥300,000, or roughly ¥350,000 for a JZX90 requiring single turbo conversion, it offers good value. Its 400–450 PS capacity suits the target, with good response from low rpm. You may replace the fuel pump as a precaution, but larger injectors are unnecessary if the originals have sufficient capacity: Mori says factory injectors respond well and are easier to control consistently.

Use at least a two layer front mount intercooler and an exhaust of 76.4 mm or more. Even with a catalytic converter, 400–450 PS is achievable. Resist adding cams for a little more power, since that would exceed the turbo and fuel system's capacity.

Keeping changes to the minimum is the advantage of this approach. F-CON SZ or V Pro is recommended for tuning: reflashing Toyota's original ECU tends to be expensive, and these systems offer finer control...

A GT2835 is excellent if 400 PS is the limit, but some drivers want more upgrade potential and the dramatic sound of an external wastegate. Choosing a slightly larger GT3037, TD06-25G or T67 can make sense. Even limited to 400 PS on stock injectors, the GT3037 suits the 1JZ well.

It gives up some low rpm torque to the GT2835 but pulls better at high rpm, so it may suit drivers who rev harder. Its ball bearing core responds quickly. The TD06-25G and T67 use plain bearings, responding less sharply but offering strong punch at high boost.

Choose according to taste. If 400 PS becomes insufficient, increase injector and pump capacity; at around 1.2–1.3 kg/cm² boost, roughly 430 PS is possible with strong midrange. HKS V Cam can extend high rpm power toward 480 PS or more.

At 400 PS the larger turbo may feel sluggish low down, but it can offer better value if further upgrades are planned.