Exhaust› Headers, Manifolds and Components

CX

Equal Length Header for 1.8L Miata NA

$740.00

SKU: HD-MIATA18-1-1

Special Order
Special Order
Ships in 4–6 weeks
Free Shipping over $200
$100 Minimum Order
30 Days Return
INSTALL DIFFICULTY
DIY PRO SHOP

Moderate — 2–4 hours

Overview

The CX Racing HD-MIATA18-1-1 is a performance header designed for the 1989-1999 Mazda Miata MX-5 NA with a 1.8L engine. It features an equal length and long tube runner design, aimed at increasing horsepower and torque. The header is constructed from stainless steel and includes a 4-1 merger collector with a 2.5" exhaust pipe and V-band flange. The second exhaust pipe connects to the factory pre-cat position.
Show original supplier description
The CX Racing HD-MIATA18-1-1 is a performance header engineered for the 1989-1999 Mazda Miata MX-5 NA models equipped with the 1.8L engine. This header is designed with equal length and long tube runners, intended to enhance both horsepower and torque output for improved engine performance. Constructed with precision, the header features 1.65" equal length runners that merge into a 4-1 collector. The exhaust pipe measures 2.5" in diameter and is equipped with a V-band flange for secure connection. CX Racing emphasizes that this product is developed in their US-based R&D center, focusing on achieving improved performance gains, excellent fitment, and straightforward installation. The equal length runner design is specifically chosen to optimize exhaust scavenging and flow dynamics, contributing to the overall performance increase.
Vehicle Symptoms
  • Check engine light for catalytic converter efficiency
  • Loss of power during acceleration
  • Exhaust smell inside cabin or under hood
  • Poor fuel economy
  • Rough idle or hesitation
Diagnostic Codes
  • P0420 – Cat Sys Efficiency Below Threshold (B1)
  • P0133 – O2 Snsr Slow Response B1 Snsr 1
Relevant Conversations
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  • p0133 miata o2 sensor slow response header
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Product descriptions are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.

Fitment

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Specifications

BrandCX
Part NumberHD-MIATA18-1-1
CategoryExhaust
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Returns & Fitment

Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

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Shipping

Orders are processed in 1–3 business days. In stock parts ship promptly from our partner network. Special-order items either aren’t currently stocked or are built to your spec — expect 4–6 weeks. If a part goes on backorder while your order is in the queue, we’ll reach out and work through discounted alternatives together.

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