Exhaust Headers for Acura Integra (1994-2001) 1.8L Engine

High-Flow T304 Exhaust Headers for 1994-2001 Acura Integra (B18B1/DC4)

What it Does: Replaces the restrictive factory cast-iron manifold with a tuned 4-2-1 stainless steel system to optimize exhaust scavenging and reduce backpressure on B-series non-VTEC engines.

The Stock Integra Flow Restriction

The factory exhaust manifold on the B18B1-equipped Integra LS, RS, and GS trims is a heavy cast-iron component designed primarily for noise suppression and manufacturing economy rather than flow efficiency. Over decades of service, these cast units are prone to heat-cycle fatigue, which often results in hairline fractures and exhaust leaks. Mechanically, the stock manifold features rough internal casting surfaces and narrow, abrupt transitions that create significant turbulence as exhaust pulses exit the cylinder head. This restriction forces the engine to expend energy pushing out spent gases, leading to increased cylinder head temperatures and a noticeable bottleneck in the mid-range powerband where the non-VTEC B18B1 already struggles.

The Engineering Solution

This performance header utilizes a 4-2-1 (Tri-Y) design specifically engineered to enhance torque across a broad RPM range. Constructed from high-quality T304 stainless steel, the mandrel-bent tubing provides a smooth, uniform internal diameter that minimizes resistance. By merging the 1.75" primary tubes into two secondary pipes before reaching the 2.0" collector, the system utilizes the kinetic energy of exiting exhaust pulses to create a vacuum effect, pulling residual gases from adjacent cylinders more effectively than the stock configuration. The CNC-machined flanges ensure a warp-resistant, leak-free seal against the engine block, while the TIG-welded joints offer the structural integrity needed to withstand high thermal loads during spirited driving. The chrome finish adds a layer of corrosion resistance while improving engine bay aesthetics.

Technical Specifications

Compatibility

• For 94-01 Acura Integra LS / RS / GS
• Made for 1.8L B18B1 Non-VTEC Models (DC4 Coupe / DB7 Sedan)

The Acura Performance Standard

The B-series engine remains one of the most respected JDM platforms for its reliability and response to mechanical optimization. Upgrading to a stainless 4-2-1 header is a fundamental step in unlocking the characteristic B18 throttle response while providing the thermal management necessary for longevity. This system ensures your DC4 or DB7 maintains peak volumetric efficiency without the weight and restriction of outdated OEM casting.

Common Questions

Will this header fit my 1994-2001 Acura Integra LS, RS, or GS?
Yes, this 4-2-1 exhaust header is engineered specifically for 1994-2001 Acura Integra LS, RS, and GS models with the 1.8L B18B1 non-VTEC engine in both DC4 coupe and DB7 sedan body styles.

Can I install this on an Integra GS-R or Type R?
This header is built specifically for the non-VTEC 1.8L B18B1 engine found in the LS, RS, and GS trims.

What material and tubing sizes are used in this header?
It is constructed from mandrel-bent T304 stainless steel with a chrome finish, featuring 1.75-inch primary tubes that merge into a 2.0-inch collector.

How does the 4-2-1 Tri-Y design help the B18B1 engine?
The 4-2-1 configuration merges the 1.75-inch primaries into two secondary pipes before the 2.0-inch collector to improve exhaust scavenging, reduce backpressure, and strengthen mid-range torque over the restrictive factory cast-iron manifold.

How is the flange constructed to prevent exhaust leaks?
The header uses CNC-machined flanges paired with TIG-welded joints to provide a flat, warp-resistant seal against the cylinder head under high thermal loads.