{"product_id":"skunk2-alpha-series-header-ep3-02-05-civic-412-05-1915","title":"Skunk2 Alpha Series Header for 02-05 Civic Si","description":"\u003cul\u003e\n\u003cli\u003eDesigned Specifically for the EP3 Civic Si \u003c\/li\u003e\n\u003cli\u003eTri-Y, 4-2-1 Header Design \u003c\/li\u003e\n\u003cli\u003eT-304 Stainless Steel Construction \u003c\/li\u003e\n\u003cli\u003eImproves Performance Across the Power Band \u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003c!-- split --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli\u003e\u003ca class=\"active\" href=\"#Description\"\u003eDescription\u003c\/a\u003e\u003c\/li\u003e\n \u003cli\u003e\u003ca href=\"#VehicleFitment\"\u003eVehicle Fitment\u003c\/a\u003e\u003c\/li\u003e \u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\n\n\u003cli class=\"active\" id=\"Description\"\u003e\n\u003ch3\u003eSkunk2 Alpha Series Header - 2002-2005 Honda Civic Si (EP3)\u003c\/h3\u003e\n\n\u003cp\u003eThe factory manifold on an EP3 is one of the biggest restrictions on the car, and getting rid of it is where the real power is. Skunk2's Alpha Series header is their answer for people who want race-header design without race-header pricing. It's patterned directly on their MegaPower headers, the ones competitive race teams have been running for years, and it uses the same engineering: equal-length, sequentially paired, stepped primaries feeding a 4-2-1 tri-Y that terminates in a 2.5-inch collector. It's a race header, so it eliminates the catalytic converter, and what you get in return is a broad, genuinely usable powerband instead of a peaky top-end-only header that leaves you flat everywhere else.\u003c\/p\u003e\n\n\u003ch4\u003eWhy Smaller Primaries Make More Usable Power\u003c\/h4\u003e\n\n\u003cp\u003eHere's what separates a well-designed header from a big pipe. It's tempting to assume bigger tubes always flow better, but exhaust doesn't work that way. Oversize the primaries and gas speed drops, and when velocity falls off you lose scavenging, which is what actually pulls spent gas out of the cylinder. You end up with a header that might post a slightly bigger peak number and feel worse everywhere you actually drive.\u003c\/p\u003e\n\n\u003cp\u003eSkunk2 went the other direction. They used the smallest primary tubes that still hit optimum overall and peak power, which keeps exhaust gas speed high all the way through the header. That's the choice you feel from the driver's seat: stronger mid-range and noticeably sharper throttle response, without giving up anything up top. The stepped primaries let the tubing grow as the gas expands, and the equal-length, sequentially paired routing means each cylinder's pulses reach the collector properly timed instead of fighting each other. That's the difference between a header that was engineered and one that was just fabricated.\u003c\/p\u003e\n\n\u003ch4\u003eBuilt From The MegaPower Playbook\u003c\/h4\u003e\n\n\u003cp\u003eNone of this was guesswork. The Alpha Series design comes out of more than a decade of racing, computerized modeling, and a lot of dyno time. Skunk2's whole goal was to give enthusiasts the same header design the company runs on its own race cars without the custom-header price tag, and it took them years to get the manufacturing where they wanted it. That heritage is the reason to buy this over a generic header that copies the shape without any of the engineering behind it.\u003c\/p\u003e\n\n\u003ch4\u003eWhat Comes In The Box\u003c\/h4\u003e\n\n\u003cul\u003e\n    \u003cli\u003eAlpha Series header\u003c\/li\u003e\n    \u003cli\u003eAdapter pipe\u003c\/li\u003e\n    \u003cli\u003eDonut gasket\u003c\/li\u003e\n    \u003cli\u003eOxygen sensor defouler\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch4\u003eInstalling Your Header\u003c\/h4\u003e\n\n\u003cp\u003eThe adapter pipe and donut gasket come with it, so you're not sourcing extra parts to tie into your exhaust. Since this is a race header that eliminates the cat, Skunk2 includes an oxygen sensor defouler in the box, so use it. And if you're running an aftermarket or wideband sensor, your O2 bung is M18 x 1.5 thread pitch. Worth knowing that before you're under the car instead of after.\u003c\/p\u003e\n\n\u003ch4\u003eWho Should Run This Header\u003c\/h4\u003e\n\n\u003cp\u003eThis is for the EP3 owner who wants serious power from a header designed by people who actually race, not just marketed to people who do. You're getting the same design language as Skunk2's MegaPower headers, with primaries sized for real usable power across the whole rev range rather than a bigger number on a graph. Bolt it on and go find out what your Si has been holding back.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eFits:\u003c\/strong\u003e 2002-2005 Honda Civic Si (EP3). \u003cstrong\u003eDesign:\u003c\/strong\u003e equal-length, sequentially paired, stepped primaries, 4-2-1 tri-Y with 2.5\" collector outlet. \u003cstrong\u003eApplication:\u003c\/strong\u003e race use only, eliminates the catalytic converter. \u003cstrong\u003eO2 bung thread pitch:\u003c\/strong\u003e M18 x 1.5. \u003cstrong\u003eIncludes:\u003c\/strong\u003e adapter pipe, donut gasket, and oxygen sensor defouler.\u003c\/p\u003e\n\u003c\/li\u003e\n\n \n\u003cli id=\"VehicleFitment\"\u003e\n \u003cp\u003e2002-2005 Honda Civic Si\u003c\/p\u003e \n\u003c\/li\u003e\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\u003c\/ul\u003e\n","brand":"Skunk2 Racing","offers":[{"title":"Default Title","offer_id":46137917374498,"sku":"SK2-412-05-1915","price":543.73,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/2218\/5701\/files\/SK2-412-05-1915_ftox.jpg?v=1785529418","url":"https:\/\/www.hybrid-racing.com\/products\/skunk2-alpha-series-header-ep3-02-05-civic-412-05-1915","provider":"Hybrid Racing","version":"1.0","type":"link"}