Borla Stainless Steel Header Install

By Squirrelbait

Well it was time to change the factory Exhaust Manifold on the 1999 TJ Sport. I didn’t even start to price out a factory replacement, as the upgrade was the only way to go in my opinion. This is a personal write-up of what I came across installing the Borla Stainless steel Header.

To make life much easier for you take the power steering pump completly off. There is an adjuster bolt to let off the tension in order to disassemble the belt. Once you have loosened it up enough to remove the belt, use the long 9/16 socket and turn the power steering pulley until you are able to fit the socket on one of the three bolts that are holding the pump to the bracket and repeat until the pump can be removed and set to the side out of the way. Now you can start to remove any plugs wires or Fuel rail clips on the intake.

NOTE ** The six fuel injector clips are a bit tricky, you must push the black strip down on the front, slide the red plastic cover up and grab the complete plug and pull all in one motion pulling up and off the injector connector – Or refer to owners manual. **

The only thing left that you might have trouble with is the main fuel rail connection to the intake. Without the proper tool we had to make our own disconnect tool out of an empty windshield washer container. We cut a strip out of the top portion of the empty container (FIG 1.0 ) approx an inch wide and just long enough to wrap once completely around the fuel line with no overlap FIG 1.2). Once you have created your own fuel line removal tool, push fuel line towards intake, (fuel rail) this gives the o-ring seal space to flex, then slide your homemade tool into fuel line connector until stopped, then gently pull until separated (Some fuel will come out when the line is pulled apart FIG 1.3) This may take a few try’s to get it right. We were in a rush; although Canadian tire sells a fuel line removal kit for roughly 17-18 dollars and this may make the removal much easier.

Fig 1.0

Fig 1.1

Fig 1.2

Fig 1.3

Now that you have everything disconnected you can start to loosen the 11 bolts off that are holding the intake and Exhaust manifold on. Be sure to disconnect the factory manifold from the pipe that runs under the vehicle for easy un-install in my case it was the factory exhaust and I had to cut the pipe (Fig 2.4), as it was one complete unit. I checked the status of the old Manifold when I removed it and was completely amazed how a 1999 could be in such bad shape. This manifold was cracked so bad that it was almost completely broke off the main pipe. (Shown below in Fig 1.4, 1.5 & 1.6)

Fig 1.4

Fig 1.5

Fig 1.6

After you have removed the intake and manifold (FIG 1.7) it is time to clean off the old Gasket from the head as well as the intake (Fig 1.8 & 1.9) I used a Knife blade from a Box cutter to scrape off the head and then used a dremel tool with a small metal brush to get it nice and clean. I also used the air die grinder with a 90 Degree angle and a Wire brush to clean the intake (pack something like cloth in the intake ports to stop any debris from getting in there as shown below in Fig 1.9).

Fig 1.7

Fig 1.8

Fig 1.9

Fig 2.0

Fig 2.1

Fig 2.2

Once everything was cleaned up it was time to fit the new gasket for the Borla exhaust Header (Fig 2.1). There is two positioning pins that locate the gasket in place to ensure it is installed correctly see Fig 2.0. Once you have the gasket in place you can attach the Borla header (FIG 2.2) and hold it in with a bolt preferably in Bolt location #1 as this is one of the bolts that does not have to go through the intake.

*** NOTE – Refer to Torque / Bolt Location Diagram for Bolt location # 1 as shown in FIG 2.3 ****

Once you have the Borla in place you can put the intake back on overtop of the Header and hand tighten the bolts back into the engine block. Now you will have to tighten the bolts in sequence as shown below in Fig 2.3

The factory torque specs say that you should only torque the bolts to 23 lbs Bolts 1-5, 8-11 and 6 & 7 are to be torque to 17 lbs only. I found that using this torque guide for tightening was just ridiculous as it did not by any means get the Borla tight enough to stop the leaks that were occurring. I was a little apprehensive to tighten them down without first checking with some reliable sources about how tight I could actually go without getting a bolt broken off in the head. I called two sources for re-assurance and both had told me that I was to basically tighten it until it was snug “with caution of course”, as they both said the similar thing, “that the bolts would take at least 35 pounds without danger “. After you have tightened the bolts down it is time to put all the wires plugs & brackets back together and re-assemble the power steering pump. Once everything is back together you are ready to fit the crossover pipe to the front of the catalytic converter. On my case I had cut the pipe when removing the old header as it was still the stock welded exhaust Fig 2.4. To join the two pipes together I had to improvise because I did not have the proper joining flange that I could have purchased from a local exhaust shop to match the Borla Crossover Flange (Fig 2.5) I cut a slab of 2 x 2 flat stock but did not have a Torch so I had to drill a few holes the diameter of the size needed in rotation of the circle and used a jigsaw to cut it out. (Fig 2.6)

Fig 2.4

Fig 2.5

Fig 2.6

Now that I had the flange to join I just made sure the pipe fit trough and then Mig welded from the back (Fig 2.7) , be sure I got a good weld so it did not leak. Now all I had to do was fit the crossover pipe onto the bottom of the header using a standard Muffler clamp to join it them together. I installed the flange gasket (Fig 2.8) and fitted the two pieces together and tightened the bolts up (Fig 2.9)

Fig 2.7

Fig 2.8

Fig 2.9

After this the time had come to test it out, once I turned the key there was a bit of a leak still heard faintly so I quickly shut it down and did one more tightening sequence to give it that last snug to stop the leak. After I started it again it was gone. The difference in the routing of the exhaust due to this modification can be shown below in Fig 3.0 being the old and Fig 3.1 being the New Free flow. Overall this was not a hard job other than the fact that the Factory torque specs that were called for not being nearly tight enough to stop the Borla from leaking, but more or less just a time consuming install.

Fig 3.0

3.1 The Free flow design