Header Installation

DC Sports, well known for its 4-2-1 design headers, recently developed a 4-1 header to add to its existing line-up. These headers were designed after the company's World Challenge Integra Type R race cars' headers, and are said to extract more horsepower throughout the powerband than any other 4-1 header. The header features large-diameter equal-length header tubes mated to an offset merge collector that provides better ground clearance, meaning you won't be scraping your header anytime soon. This header is said to have been dyno-proven to provide excellent top-end torque and power, as well as being CARB exempt and available in both ceramic-coated mild steel and a polished stainless steel.

Follow along as Frank from DC Sports installs a stainless steel 4-1 header onto a '99 Civic Si.

The DC Sports four-into-one stainless steel header features large-diameter equal-length header tubes mated to an offset merge collector.
The DC Sports four-into-one stainless steel header features large-diameter equal-length he

Available in both ceramic-coated mild steel and polished stainless steel, these headers are CARB-exempt and are applicable to many Honda/Acura engines.
Available in both ceramic-coated mild steel and polished stainless steel, these headers a
First, raise the car and support it on jackstands. Remove the splashguard on the lower portion of the vehicle, located directly underneath the engine bay. Using a 12mm socket wrench, unbolt the two nuts on the factory header downpipe that connect to the lower exhaust manifold support bracket.
First, raise the car and support it on jackstands. Remove the splashguard on the lower por

Unbolt the header downpipe from the catalytic converter by unscrewing the 12mm nut and removing the 14mm bolt for the two spring bolts at the collector flange. You will then unbolt three bolts on the header downpipe from the upper exhaust manifold by using a 14mm socket wrench.
Unbolt the header downpipe from the catalytic converter by unscrewing the 12mm nut and rem
Remove the header downpipe from the upper exhaust manifold. Disconnect the oxygen sensor. You will be repositioning the oxygen sensor onto the DC Sports header, so don’t put this part away just yet. Are your arms tired yet?
Remove the header downpipe from the upper exhaust manifold. Disconnect the oxygen sensor.

Use the 14mm socket wrench to disconnect the lower exhaust manifold support bracket. Remove the oil dipstick; you will need to take this out in order to unbolt the exhaust manifold heat shield.
Use the 14mm socket wrench to disconnect the lower exhaust manifold support bracket. Remov
Remove the four 12mm heads that bolt the exhaust manifold heat shield to the upper exhaust manifold. It will be a tight squeeze, so be sure to use a flex-joint adapter on your socket wrench. Remove the heat shield and store it with your stock header; you will no longer be able to use this heat shield.
Remove the four 12mm heads that bolt the exhaust manifold heat shield to the upper exhaust

Use the 12mm socket wrench to unbolt the seven bolts and two nuts that keep the upper exhaust manifold attached to the cylinder head. Again, this will require the usage of a flex-joint adapter on your socket wrench in order to fit around the header tubing.
Use the 12mm socket wrench to unbolt the seven bolts and two nuts that keep the upper exha
Remove the upper exhaust manifold section and place it with the rest of the factory header components. You can reuse the manifold gasket if you choose, but it wouldn’t hurt to use a new gasket or an aftermarket metal gasket. This will ensure a tight seal between the cylinder head and the header, eliminating any exhaust leaks.
Remove the upper exhaust manifold section and place it with the rest of the factory header

Remove the oxygen sensor from your factory header downpipe...
...and place it onto the DC Sports header. Use anti-seize when transferring the oxygen sensor to prevent any unwanted rust from building up.
...and place it onto the DC Sports header. Use anti-seize when transferring the oxygen sen

Attach the donut flange to the header collector that connects to the catalytic converter. Working from the bottom up, wiggle the header upward, driver-side up first. Line up the upper portion of the header to the cylinder head studs, then place the upper header to the cylinder head and hand-tighten the nuts to keep the header in place. Use anti-seize on all the bolts and nuts that are included with the DC Sports header.
Attach the donut flange to the header collector that connects to the catalytic converter.
Torque down all the nuts and bolts to factory specs while using an inside-out tightening pattern. Tighten all bracket nuts, as well. You can loosen the top hanger bolts to make the bottom portion easier to bolt down.
Torque down all the nuts and bolts to factory specs while using an inside-out tightening p

Use an all-purpose cleaner to polish off the header after the installation. This will remove any stains and fingerprints encountered during the install, and will keep your new DC Sports stainless steel header looking brand new.
Use an all-purpose cleaner to polish off the header after the installation. This will remo