It took a while, and over $1000 in parts, but I have just about completely replaced my exhaust system on my 2000 X. I started with a Gibson 2.25" catback, which was easy to install. Follow the directions, and it takes about 45 minutes or so. Adds a nice exhaust rumble, with the drawback being a pretty loud drone over 60mph. Oh well, no big deal.
Then I turned to my cracked (again! been replaced 2-3 times each!) exhaust manifolds.
I decided to go with Thorley long tube headers. They may not really add too much performance wise..a couple percent HP unless you modify the intake, port and polish, grind valves, and then get a custom ECU tune. I'm not doing all that until I rework the entire engine.
I bought the exhaust headers and gaskets, new short studs, stud nuts. I also bought a set of new intermediate pipes, as they're a bit bigger than the factory pipes, and I needed them to insert my new cats. Yep, I opted to stay completely street legal in TX and replace the "defective" cats with new "equivalent" cats. I got a set of Flowmasters with 2.25" pipe, that are maybe 4" in diameter and about 9" long or so. I found two places in the middle of the intermediate pipes that I could cut out a section and replace with the cats. This of course meant I had to relocate the downstream O2 sensor, which required moving the bungs.
I bought a set of bungs, pre-installed the mid pipes, measured and marked where I wanted to insert the new cats, pulled the mid pipes back out, and cut those sections out, only to discover they're really only about 2" OD, while the CATS were 2.25" ID. I then had to run out and get some exhaust reducers to bridge the diameter difference, and then trim them and the cat end tubes down to keep the length short enough. I then had to reinstall all of that mocked up midpipe sections back in place again with pipe clamps on the Cats so I could get the final position, and then tack weld the pipes to the reducers. I decided doing that I liked the fit of the "u" pipe clamps on the cats themselves and that made them more serviceable, so I left those in place, and just welded up the reducers to the midpipe sections on each end.
I also had marked the O2 locations, and drilled those holes, dremeled them out to fit in bungs, and welded up the new bungs. Then I had to put all that back in place again once it cooled.
I tried reusing the old O2 sensors, but I had banged them up pretty good, and I had to splice in "extensions" for all of them but the driver's side front one to reach the new locations on the headers and midpipes. That was pretty easy work with some heat shrink butt connectors. The old O2 sensor on the passenger rear had thrown a code a couple of times after running at high speed for long times, so I ordered all new sensors and swapped the extensions I made to them, and put those in. So far, no codes.
The fuel mileage is about the same as before more or less. Power seems similar. It is really hard to tell. The engine is at 215,000 miles, and is a little tired, but not too bad. Key is no more puffing cracked exhaust manifolds.
Then I turned to my cracked (again! been replaced 2-3 times each!) exhaust manifolds.
I decided to go with Thorley long tube headers. They may not really add too much performance wise..a couple percent HP unless you modify the intake, port and polish, grind valves, and then get a custom ECU tune. I'm not doing all that until I rework the entire engine.
I bought the exhaust headers and gaskets, new short studs, stud nuts. I also bought a set of new intermediate pipes, as they're a bit bigger than the factory pipes, and I needed them to insert my new cats. Yep, I opted to stay completely street legal in TX and replace the "defective" cats with new "equivalent" cats. I got a set of Flowmasters with 2.25" pipe, that are maybe 4" in diameter and about 9" long or so. I found two places in the middle of the intermediate pipes that I could cut out a section and replace with the cats. This of course meant I had to relocate the downstream O2 sensor, which required moving the bungs.
I bought a set of bungs, pre-installed the mid pipes, measured and marked where I wanted to insert the new cats, pulled the mid pipes back out, and cut those sections out, only to discover they're really only about 2" OD, while the CATS were 2.25" ID. I then had to run out and get some exhaust reducers to bridge the diameter difference, and then trim them and the cat end tubes down to keep the length short enough. I then had to reinstall all of that mocked up midpipe sections back in place again with pipe clamps on the Cats so I could get the final position, and then tack weld the pipes to the reducers. I decided doing that I liked the fit of the "u" pipe clamps on the cats themselves and that made them more serviceable, so I left those in place, and just welded up the reducers to the midpipe sections on each end.
I also had marked the O2 locations, and drilled those holes, dremeled them out to fit in bungs, and welded up the new bungs. Then I had to put all that back in place again once it cooled.
I tried reusing the old O2 sensors, but I had banged them up pretty good, and I had to splice in "extensions" for all of them but the driver's side front one to reach the new locations on the headers and midpipes. That was pretty easy work with some heat shrink butt connectors. The old O2 sensor on the passenger rear had thrown a code a couple of times after running at high speed for long times, so I ordered all new sensors and swapped the extensions I made to them, and put those in. So far, no codes.
The fuel mileage is about the same as before more or less. Power seems similar. It is really hard to tell. The engine is at 215,000 miles, and is a little tired, but not too bad. Key is no more puffing cracked exhaust manifolds.