Preparation

• Download and refer to the above images for a larger and more detailed version.
• Safety: always use a lift (don't we all wish), or if you are using a floor jack, be sure to use adequately rated jack stands. Wearing glasses or goggles is also recommended when working underneath the car as falling bits of carbon and dirt can make work difficult
• Let the engine cool until you feel comfortable working near the engine and near the catalytic converter which is very, very hot. Opening up your hood and having a fan blowing in front of your car will help cool things down faster. The stock iron manifold will retain lots of heat for a long time. It will probably help if the engine is still a bit warm when you work on it. Nuts will be a bit easier to turn.
• Soak the nuts and bolts with "penetrant" if you think you'll have a hard time taking them off.
• Clean the inside piping of the new headers by pushing a rag through it. This will remove any metallic pieces or dirt that may cause some problems with the catalytic converter downstream.
• Gather all the needed tools together:
  1. 8mm socket and wrench
  2. 10mm socket and wrench
  3. Extra long socket wrench or normal wrench with extension pipe
  4. Socket extension for your socket wrench
  5. Vise grip pliers (to hold the spring loaded pieces together if you're working by yourself)
  6. Bolt/nut "liquid penetrant"
  7. Lockit compound
  8. Aftermarket header
  9. Aftermarket piping
  10. Supplied gaskets
  DC Stainless versus Stock Manifold
  

  Removal

  • On both disassembly and removal, it helps to get everything in place and partially loosened/tightened before doing final removal or assembly.
  • Follow the diagrams to see which bolts and nuts need to be removed.
  • Start by removing the heat shield.
  • Next work on the pipe that connects the exhaust manifold to the catalytic converter.
  • The actual exhaust manifold itself should be taken off last.
  • Notice that the two bolts that attach the stock exhaust manifold to the bracket is torqued much tighter than the others. This is where the extra long socket wrench will come in handy.
  • If you have an RS/LS be sure to disconnect the Oxygen Sensor from the pipe.
  • Keep the metallic gasket that is in between the exhaust manifold and the engine. Clean the gasket with a rag and be careful since the gasket is sharp at some points. Replace the gasket if it is in really bad condition.
  • You'll need an extension (and preferably a deep socket) to remove the nuts attaching the exhaust manifold to the engine.
  • Remove the circular gasket that should be attached to the bottom pipe near the catalytic converter. You'll need to reuse this one too unless it is in bad condition.

  Installation

  • Use Lockit compound on all threads. Be sure to use a compound which can be loosened with hand tools (read the package).
  • Install the new headers first onto the engine. Don't forget to put on the clean gasket. Note that Acura recommends using new self locking nuts at this point. Most people consider it optional, especially since they cost $1.50 each.
  • You won't be using the stock heat shield anymore.
  • Place the Honda ring gaskets, which should be supplied by the headers manufacturer, onto the indicated position of the downpipe in the diagram.
  • Also place the other circular gasket back onto the new downpipe.
  • To attach the downpipe to the catalytic converter, you'll have to use your fingers to press against the spring loaded bolts or utilize vise grips to hold the pieces together while using a piece of cloth to protect the header.
  • Double check all nuts and bolts to be sure that they are tight. You can even torque them to spec if you have a torque wrench. This is especially preferable on the manifold studs connecting the header to the head.
  • Clean the headers with a rag containing a little bit of grease remover. This is to ensure that no grease is on the headers so that they will not stain due to the intense heat. For ceramic headers, be careful not to stain them at all as they are difficult to clean. Using a pair of mechanics gloves may be your best bet.
  • Start your car up and check for exhaust leaks.
  • Recheck the nuts after a week.

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  DC Headers vs. Stock

  I compared my car to my friend Henry's car again. This was after Henry installed stainless steel DC headers. Henry now has the Trust Airinx filter with fresh air tube, Trust Exhaust, and DC stainless steel headers. I now have the Trust Airinx filter with fresh air tube, stock exhaust, and stock exhaust manifold. Henry has 3/4 tank gas, 45 series tires on 16 inch wheels (about .4% shorter than stock), and had his valve adjustment done about 3500 miles ago. I had about 3/4 tank gas, 55 series tires on 15 inch wheels and had a valve adjustment done about 25 miles ago. So basically we are now pretty even except for the Trust exhaust and DC headers.

  We did the same street launch going 5-7 mph in first gear. I took off first again. I shot up to second gear quickly with Henry shifting a split second after me. We were dead even. He was a little behind my side view mirror. 8000 rpm in second gear, I shift to third quickly with lift throttle and then floor it again. Henry does the same thing a split second later also. Right after the shift to third, we are doing about 65-70 mph. All of the sudden I can see Henry starting to pull ahead. He shoots past me! I estimate he was going about 5 mph faster than me as he passed my front bumper. Seems like the headers helped quite nicely.

  Analysis: Again, I was able to hold Henry off all the way to redline in second gear. At the lower gears, the stock Integra is able to have sufficient torque to keep up. However, once in third gear, Henry's torque and HP advantage is able to show. There is a big jump going from 2nd to 3rd gear in ratios: 1.900 to 1.360. Shifts to other gears are only increased by .3 compared to the .6 increase when going from 2nd to 3rd.

  GS-R Ratios (:1)        RS,LS
  1st     3.230           3.230
  2nd     1.900           1.900
  3rd     1.360           1.269
  4th     1.034           0.966
  5th     0.787           0.714
  Final   4.400           3.000
  

  Anyways, it seems like the my stock GS-R doesn't handle the decrease in ratio (numerically) as well as Henry's. In third, Henry pulled several car lengths ahead of me. I can tell that he was accelerating at a faster rate than I was, that's for sure. In fourth, I was hopelessly behind him.

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  Shawn's Dyno After DC Header's Install
  
  DC Stainless Installed
  
  After 2 Days