Throttle Bodies & IAC

Throttle Bodies, IAC Valves & Fuel Pressure Regulators

The throttle body is the air metering and control point of any fuel-injected engine — the gateway through which all intake air must pass, controlled by the throttle plate that the driver manipulates through the accelerator pedal. A restrictive throttle body limits maximum air flow and therefore maximum power; a correctly sized, quality throttle body allows the engine to breathe to its full potential while maintaining precise throttle control and idle stability.

With 71 products from Holley EFI, Holley Sniper EFI, and MSD, our throttle body range covers both stock-style replacements and high-flow performance units for LS, LT, and EFI-converted traditional V8 applications.

Performance Throttle Bodies — Size and Flow

Factory LS throttle bodies are competent components for stock and mild performance applications, but as power levels increase and airflow demand grows, the factory bore diameter becomes a restriction. Larger bore performance throttle bodies — available in diameters from 90mm to 102mm for LS applications — allow the engine to breathe freely at high RPM and high load, recovering power that would otherwise be lost to throttle body restriction. Billet construction and precision machining provide the dimensional accuracy required for consistent throttle response and idle quality.

Throttle Body Adapters and Spacers

Throttle body adapters allow the fitment of non-standard throttle bodies to various intake manifold configurations, opening up the possibility of using high-flow units from other applications or facilitating specific EFI conversion designs. Throttle body spacers create additional plenum volume between the throttle body and intake manifold, which on some configurations can improve air distribution and produce measurable power gains in the mid to upper RPM range.

Idle Air Control Valves

The idle air control valve maintains consistent idle speed across varying engine loads — the demands of air conditioning, power steering, electrical loads, and warm-up enrichment all affect idle speed, and the IAC compensates by modulating a bypass air path around the closed throttle plate. A faulty IAC causes unstable idle, hunting, and stalling — particularly noticeable when coming to a stop after highway driving. Our IAC replacement and upgrade range covers the most common LS and EFI conversion applications.

Fuel Pressure Regulators — Consistent Pressure for Consistent Fuelling

The fuel pressure regulator maintains constant differential pressure between the fuel rail and intake manifold — ensuring injector flow rates remain consistent regardless of engine load and manifold pressure changes. An adjustable fuel pressure regulator allows fine-tuning of base fuel pressure to optimise fuelling across the operating range, and is particularly useful on forced induction applications where manifold pressure reference is essential for maintaining consistent injector differential pressure under boost.