!EGR Free Mod

Tools & parts you will need:
10 mm socket
  • 15 mm socket
  • 3 inch extension
  • Ratchet
  • Torque Wrench
  • 1998- 1999 EGR pipe 12556643 (comes with o-ring) (2000 model has a different pipe part number)
  • EGR pipe exhaust manifold gasket p/n
  • Dremel tool or hack saw
  • The part number for the O-Ring gasket on the EGR pipe is 12557932.  Just in case you were wondering.  This gasket comes on the EGR pipe when ordered.
    Gasket between AIR pipe and exhaust manifold 12553617.
    Expect approximately 20 minute – 60 minute install time 
      July 8, 2000
    Car:  1999 Z28 Camaro, 13,900 miles
    Installers:  Eric and Kelly Barger
    Email:  help@installuniversity.com
    People who helped us from major tech talk to general advice:
    Elmer Boggs (
  • Jack (Jack98SS)

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    Perform all these installs at your own risk.  Know how to use all of your shop equipment and take necessary safety precautions when performing ANY modifications and or maintenance items to your vehicle.  Seek the advice of a paid professional and do not substitute this publication for the advice of a paid professional.  This product is how we accomplished our installs and is not meant to be carved in stone.  We are not responsible for a mistake, misprint, or any other error found in this guide.  This guide is intended as a supplement and not to be your only source of information.
    Purpose:   The EGR pipe protrudes down behind the throttle body restricting airflow.  Cutting down the part of the pipe that protrudes down behind the throttle body will provide better flow into the intake manifold.  This modification will probably provide 3 rear wheel horsepower at best.  Every bit helps and that is way this modification is still being done.  Still wondering what in the world we are talking about?  Click here to visit the bottom of this page to see a before and after view.
    You will notice on some install pages they do not recommend removing the entire EGR pipe to perform this modification.  The pages suggest you just undo the one 10 mm screw holding the EGR pipe to the intake manifold and bending the pipe back a little bit.  
    We DO NOT agree with that at all.  We bent our pipe back for curiosity purposes and started a big problem with the rubber o-ring on the pipe.  Because we did not get the bend back to the original form, half of the o-ring would sag down into the manifold and cause a major vacuum leak.  This will cause your car to idle very SPORADICALLY and you can notice the leak by the LOUD whistling sound coming from under the hood.  We suggest taking an extra 10 minutes and removing the pipe all together.  After all, you will be able to make a better cut and decrease your chances on cutting something else in the engine compartment.
    We also recommend you buy a replacement o-ring gasket to replace the one on the pipe when you take it out.  The heat over time weakens the gasket and makes it real easy to sag down and cause a vacuum leak. 
    You also should have a replacement gasket for the EGR pipe to exhaust manifold connection.  It is a metal gasket that is really easy to flake apart.  This will cause a loud ticking sound if it does not seal back properly.
    Preface:  Please read this paragraph before proceeding.  Please pay close attention to Step 7.  This is a critical step and must be read before you make the same mistake we did!
    Before you start into this install be sure you know how to use all of your shop equipment.  Take your time and be careful.
    1.  You need to locate the EGR valve (see blue arrow in Figure 1).  
    Figure 1
    2.  Disconnect the electrical connector that plugs into the EGR valve (see blue arrow in Figure 2).  Take a good look at how the EGR valve is positioned before you remove it.  Remove the two (2) 10 mm bolts that hold down the EGR valve (see red arrow in Figure 2)
    Figure 2
    3.  Now you need to remove the two (2) 10 mm bolts that hold the EGR pipe to the exhaust manifold (see blue arrows in Figure 3).  Watch out for that gasket, it is very fragile and might split into pieces if you are not careful.  We got a new gasket to replace the old one because we also messed it up when we bent the pipe.  The replacement gasket part number is 12553617.
    Figure 3
    4.  Now you need to remove the 10 mm bolt that attaches the EGR pipe to the intake manifold (see red arrow in Figure 4).
    Figure 4
    5.  Remove the EGR pipe mounting 15 mm bolts from the EGR valve bracket (see blue arrows in Figure 5).  
    Figure 5
    6.  Remove the EGR pipe by twisting the EGR pipe around to get it out from the wire that runs in front of the EGR valve.  Just take your time and you will get it out from under it.  Place a rag over the opening take a look at the end that extends into the intake manifold (the end we want to cut).  We cut our EGR pipe 1.25 inches up from the bottom of the pipe section that protrudes into the intake manifold (see Figure 6). The 1.25 inch measurement is as good of a place as any.  It just so happens that there is a seam in the pipe right at measurement and that is how we chose the spot to cut.  Notice we do not have a rubber gasket on the pipe.  We took it off before cutting the pipe.
    Figure 6
    7.  Look at Figure 7 to see a picture of the EGR pipe after the cut has been made.  Be sure to grind down the cut edge so that the cut looks like it was from the factory.  This ensures that you don't leave any metal particles to get sucked down and thrown into your engine's cylinders.  Be sure to replace the o-ring gasket back onto the pipe.  We used a brand new o-ring to be safe.
    Figure 7
    8.  You need to tighten the EGR pipe 15 mm mounting bolts to 37 ft-lb (see blue arrows Figure 8).
    Figure 8
    9.  Tighten the two (2) 10 mm bolts that hold the EGR pipe to the exhaust manifold to 15 ft-lb (see blue arrows Figure 9).  Don't forget to place the gasket back in there.  
    Figure 9
    10.  This next step is very critical!  Please pay close attention!  You need to use extreme caution when tightening the EGR pipe back up to the intake manifold.  DO NOT tighten the bolt over 89 in-lb or YOU WILL STRIP the brass heli-coil out of the manifold!  See Figure 10 for that end result.
    Figure 10
    This is not a desirable situation at all!  I was lucky and was able to JB Weld the brass heli-coil back into the Intake Manifold.  Some people are not that lucky and have to fork out some major money, as much as a $1000 for the intake manifold and installation. 
    Tighten the 10 mm bolt that attaches the EGR pipe to the intake manifold to 89 in-lb.  Please do not exceed that measurement!  Use a torque wrench!!  You might want to use a 3 inch extension to rise above the EGR pipe if you torque wrench is to fat. 
    11.  Now you need to place the EGR valve back on bracket and tighten the 10 mm bolts twice (see blue arrows in Figure 11).  Yes twice.  Tighten them to 89 in-lb the first go around.  Then tighten the bolts on up to 18 ft-lb.
    Figure 11
    12.  You can see a view through the front of the throttle body and compare it to a picture after the cut has been made (see Figure 12).  Notice on the "before" picture you can clearly see the EGR pipe extend down.  The "after" picture you can not see the pipe at all.  You are just cutting the pipe so the air can have a less restrictive path into the intake manifold.
    Figure 12
    Comments:  When you are strapped for cash free modifications look better and better.  Do not be surprised if you see a slight increase in engine temperature (only a few degree's and should only be noticeable using a scan tools such as Auto Tap) because the re-circulated gases (which help cool the cylinders) will have more trouble entering the system as they were intended.