NOTE: For OEM STi and Cosworth intake manifolds only, if you have a Process West intake manifold, please use THIS part number.

Version WITHOUT the throttle body, linked HERE.

In the hunt for more horsepower, Subaru owners can be limited by their OEM throttle body. The OEM units just aren’t big enough to meet the demands of larger upgraded turbochargers. For years those who were seeking to upgrade this component were forced to use inferior aftermarket alternatives. These aftermarket throttle bodies were prone to issues like sticking, poor idle quality, and difficult installation. IAG is pleased to announce that these owners are no longer forced to compromise drivability for horsepower. With the introduction of our new adapter plates, owners are able to upgrade their OEM throttle bodies with a larger OEM quality unit that is sold separately.

The Big Bore throttle body offers a 76mm bore which is nearly 25% larger over stock. Best of all, the installation is much easier than other options previously available. Simply drill out the rivets holding the motor to your OEM Subaru throttle body, remove the motor assembly, and install it to the throttle body using the supplied replacement rivets. No complicated disassembly, no springs, and the OEM connector is plug and play.

The IAG adapter plate is designed specifically to work with the OEM STI or Cosworth Intake Manifold. The plates are machined from 6061 aluminum and feature an O-ring sealing surface. Each adapter plate includes all the necessary hardware to complete the installation. The adapter plates are available in anodized black or natural silver finish.

Fits *2004-20 Subaru STI, 2006-07 WRX, and the 2004-08 Forester XT. The 2004 STI requires a riveted throttle body. Confirm throttle body style and consult with your tuner before ordering.

Fitment Notes:

• Intended for vehicles making 600+ HP with front mount intercoolers
• ECU calibration is required – Consult with your Tuner before ordering.
• Big Bore Throttle Body is not included with the kit.
• Installation requires a Subaru throttle body with rivets attaching the motor. Not compatible with clip style Subaru throttle body.
• Custom piping / fabrication may be required for installation
• Not compatible with OEM style MAP sensors

Adapter Kit Includes:

• (x1) IAG Aluminum Adapter Plate
• (x4) M6x50mm Low Profile Socket Head Cap Screws
• (x4) M6x20mm Low Profile Socket Head Cap Screws
• (x4) Small O-rings
• (x2) Large Adapter Plate O-rings
• (x7) Rivets