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Exhaust› Headers, Manifolds and Components

K Tuned

4-2-1 Race Header

$284.99 $282.14 Save $2.85

SKU: KBH-CSI-409

In Stock
In Stock
Ships by Sep 12
Free Shipping over $200
$100 Minimum Order
30 Days Return
INSTALL DIFFICULTY
DIY PRO SHOP

Moderate — 2–4 hours

Overview

The K-Tuned Civic Si header is a 4-2-1 Tri-Y design header constructed from 409 Series Steel. It features 3/8 inch thick CNC cut flanges and a 2.5 inch outlet. This header is designed to optimize performance for the K20Z3 engine.
Show original supplier description
The K-Tuned 4-2-1 Race Header is engineered to enhance the performance of the 2006-2011 Honda Civic Si, specifically for vehicles equipped with the K20Z3 engine. This header utilizes a 4-2-1 Tri-Y design, which is known for optimizing power output across the RPM range, providing a balance of low-end torque and high-end horsepower. Constructed from durable 409 Series Steel, this header is built to withstand high temperatures and resist corrosion. It features robust CNC-cut 3/8-inch thick flanges for a secure and leak-free seal, and a 2.5-inch outlet diameter designed for optimal exhaust flow. The design aims to provide good power gains and is offered at a competitive price point. Fitment is specific to the 2006-2011 Honda Civic Si Sedan or Coupe models. However, minor customization to fit the exhaust may be necessary, and while it typically bolts up to most aftermarket exhaust systems, fitment cannot be universally guaranteed.

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

BrandK Tuned
Part NumberKBH-CSI-409
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.

Free shipping over $200 in the continental US. Alaska, Hawaii, U.S. territories (Puerto Rico, U.S. Virgin Islands, Guam, American Samoa, and the Northern Mariana Islands), and international orders carry surcharges — most appear at checkout. Some exceptions (LTL freight, or suppliers who quote freight only after we place the order) won’t. In those cases we’ll reach out with the exact charge before your order moves forward.

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