DC Sports Header for 02-06 RSX/02-05 Civic Si

DC Sports 4-1 Header - 02-06 Acura RSX & 02-05 Honda Civic Si (EP3) K-Series

If you've got an 02-06 RSX or an 02-05 Civic Si, the factory exhaust manifold is one of the biggest things holding the K-series back. The stock piece is a restrictive log built to pass emissions, not to make power, and you can feel the engine fighting to push exhaust through it. This DC Sports 4-1 shorty header fixes that with true equal-length runners, large-diameter primaries, and a smooth 2.5" collector, all mandrel bent so the exhaust flows clean. The payoff is better scavenging, lower backpressure, stronger mid-range torque, and real top-end power, with a cleaner VTEC crossover and sharper throttle response. It comes in polished stainless or ceramic coated, and the ceramic is worth it if you push the car hard.

Why the Factory Manifold Chokes It

The stock manifold's runners aren't equal length and the diameter's too small, so exhaust from different cylinders reaches the collector at different times and creates backpressure. The engine burns power just shoving its own exhaust out. A proper 4-1 header with equal-length runners times all four cylinders to the collector together, so scavenging improves, the head breathes cleaner, and the engine makes power without working as hard. You feel it the moment you get on the throttle.

Ceramic Coated or Polished Stainless

You've got two finishes. Polished stainless looks clean in the bay and fights corrosion. The ceramic-coated version does both of those and adds real thermal protection: the coating is rated to 1200°F and applied thick, and it keeps radiant heat in the exhaust instead of dumping it into your engine bay. That means lower intake temps, less heat beating on the hoses and plastic around the engine, and a cooler bay in summer traffic or on a hard run. For street driving, polished stainless is fine. For track days or hard driving, the ceramic is worth the extra cost.

Shorty Design, Keeps Your Factory Cat

This is a shorty header, so it bolts directly to your factory catalytic converter. You're not replacing the cat, cutting anything, or doing custom fab work, and the compact design works with your OEM setup. That's the whole advantage: you keep your emissions system intact and stay street legal while still getting a real power gain, instead of being forced to choose between the two. The secondary O2 bung is in the factory location, so your sensor goes right back where it belongs.

Built Right, Not a Cheap Knockoff

This header is T-409 stainless steel with thick CNC-machined flanges and precision mandrel-bent runners. Mandrel bending keeps the pipe's full diameter through every bend, so exhaust flows smooth with no sharp transitions or turbulence, and every joint is TIG welded inside and out. It's built to survive years of high-rpm abuse without warping or leaking, which is exactly where cheap knockoff headers fall apart, cracking at the welds and warping the flanges until you're chasing ticks and leaks six months in. This one bolts on and stays sealed.

Real-World Power

Be realistic about the gains, because that's how you stay happy with the part. On an otherwise-stock K-series, this header is good for roughly 10-14 hp depending on the engine, with the real story being stronger mid-range where you actually drive and a harder pull past 6000 rpm when VTEC comes in. It's not a 30-hp part on its own, and anyone who tells you a header alone does that is selling you something. Paired with an intake and a tune, though, it's a core piece of a setup that genuinely moves. You also get a deeper, crisper K-series exhaust note under load, without the tinny rasp or highway drone of a cheap part.

CARB Legal in All 50 States

This header is CARB compliant under Executive Order D-370-14, so it's legal to run in all 50 states and won't fail a smog check. Because it's a shorty design that keeps your factory catalytic converter, your emissions setup stays intact, with nothing to swap at inspection time. It's a real performance upgrade that's actually legal, which beats gambling on an off-road header you can't pass testing with.

What You Get

• DC Sports 4-1 shorty header for the K-series
• True equal-length, mandrel-bent runners with a 2.5" CNC-machined collector
• T-409 stainless steel, TIG welded inside and out
• Thick CNC-machined flanges
• Factory-location secondary O2 sensor bung
• Shorty design, bolts to the factory catalytic converter
• Your choice of polished stainless or ceramic-coated (1200°F) finish
• CARB compliant, legal in all 50 states (EO# D-370-14)
• One header per order

Fitment

• 2002-2006 Acura RSX (Base)
• 2002-2005 Honda Civic Si (EP3)