Gutting My Cat Got My Power Back!! w/pics For anyone with power loss and hasn't gutted their catalytic convertors... Ok. so for the past few weeks with a guttless car, no power on the highways or hills for that matter and the feeling that I was towing a trailer behind. I finally found out the problem. I thought it was a tranny for the longest. But this weekend I gutted both catalytic convertors. For my car (1990 2.3L LX N/A) there is 2 catalytics). The one that was plugged 90% was the closest one to the engine. Probally due to the fact that its the first to get hit with all the crap coming out of my engine. I scanned a sample of the honey type cone stuff that makes a catalytic convertor. Heres how a convertor inside should look like. and heres what 90% of mine looked like inside I'm not too sure what cause such plugging but I did have a tranny fluid leak into the vacuum lines which leads to the intake, so I suspect it was some of the problem. For any of thoses who care how I did it then read on. I did get some hints and tips from some here at the forum so I thank you. NOTE: make sure to have good ventalation and wear a mask! 1) I un bolted the flang from the mainfold and the flang from the pipe to the muffler 2) I took off the pipe that has both cats attached to it 3) To save time I only cut the pipe in 2 areas to access the inside of the cats. In the center of both looked sorta like ( | = the cuts I made) {Manifold}=pipe={catalytic1}=|==pipe==|={catalytic2}=pipe=={muffler} 4) I marked the pipe with a file in one spot where I was cutting the pip so when I weld the cat back to the pipe, I could use the line as a guide to make sure I line the pipe and cat backup as acurate as possible. 5) After I made the 2 cuts (cutted close to the opening of the cat) I locked down the catalytic convertor in my vice (the cutted end up), took a long large flat head screw driver (a long punch would work too) and started chiseling the honey like cone inside. 6) Took a bit of time but the stuff shatters pretty good and fell out farely easy. For the smaller cat (closest to the manifold) theres 2 rubber bands you have to take out (I use long needle nose plyers), and the larger cat (closest to the muffler) theres one rubber band and a wire mesh you have to remove. 7) After the both catalytic convertors were gutted, I lined them up to the guide lines I marked off earlier, and welded each cat to pipe. (if you don't have a welder you can use a piece of pipe thats a little bigger and use muffler clamps) 8) I then bolted the pipe back to the manifold and muffler pipe ( I had to get a new universal flange for the manifold). Finished! It took me one hour with my brothers help to finish this job. I got all my horse power back (as much as you can get for a 2.3 heehee), The cars a bit louder but more like a muscle car sound , But it was my problem all along for the power loss. My car did stall a couple times starting up after the job, but its like it had to adjust to the free flowing exhaust. Since that job I've restarted my car with no stalls at all. To be honest you probally only need to gut the smaller one up front to the manifold as thats the one that gets hit the hardest. I just did the other one cause everything was down to do anyways and I wanted a bit more power . Anyways my Dad is the one who suggested this as I thought it was a tranny problem. He told me the problem is like if you covered your mouth, and one nostril and tried running your house 5 times only breathing threw 1 nostril, thats how my car felt. Anyways thanks for all your input. it really helped .
How much louder did the exhaust note get? I am thinking about cutting the cats off and putting a single pipe to the muffler...so I would really like it to be louder than it is right now
Ya, it did make a little bit more noise, but a real low hum sound if that makes any sense. You will probally get less if you run a straight pipe. I bit more work, thats why I left mine, not as much to it and I don't mind the louder exhaust considering the power I got back. Now I could be totally wrong. But I assume having a hollow cat is more humming then a straight pipe. My 2 cents anyways.
I was hoping for more sound than I have with stock pipes. I am also going to put a better muffler on too. Most likely a FlowTech Afterburner. So maybe thats worth 1 or 2 hp.
Ok I read your first post and sounds like you have done a great detailed job. May want to post it in the Tech sticky to help out newbies do a simple cheap modification. I do have a question, I dont have a welder so when you said to use a larger diameter pipe to connect it and to use muffler clamps. Will this work to seal it back up? I am considering doing this and If I do I am thinking to use a pipe that is larger as you mentioned and slide it over, using JB weld at each end on the interior to get a Gasket type seal and use the Muffler clamps on top to hold it all in place. What do you think?
Well alot of exhaust systems out there rely on large pipe over smaller pipe and muffler clamp to hold them together, so i don't see why it wouldn't work. Just be sure to have it as tight as you can so it don't lossen apart. You just have to be sure the bigger pipe is just big enought to slide over the smaller. Someone suggest to me a while back that if you can get your hands on a pipe stretcher and stretch the opening on a piece of pipe that was the same original size as the cat pipe, it would work. I have a stretcher but never tried that approach. Anyways lots of different ideas. Maybe you could find a local welder to just weld the pipes back together ?
Yeah I am going to look into that and a Local welder wont have to worry about any legal things due to gutting the cat because he is not a mechanic. I dont know the first thing about stretching pipe yet but I will look into that also. Thanks
I'd suggest you where a mask when gutting the cats...there are some VERY nasty substances that get turned to powder while gutting them (and become airborn and find their way to your lungs). Stinger
I have learnt my lesson when I was cleaning parts before I began to paint. I had a bucket of CLR (diluted as recommended), a bucket of water, a can of engine degreaser, and plenty of oil soaked parts. Well the Garage was open and I have a wall mounted shop fan and al of the windows open you could not have a book in there open without the pages flying. Well I was in there cleaning away on parts, soaking them in the CLR then using a brush and rag to get the gunk off. The engine degreaser was helping some also but not as well as the CLR. I was getting a little light headed and was mad because I had plenty of ventilation in there and headed for the house. I woke up about a half hour later when my puppy was let out to go to the bathroom, then woke up in the living room laying on the couch 3 hours later and finally woke up with a massive headache the next day 13 hours after that. I will defiantly be getting a mask.
Very good point stinger. I will edit my post in the sticky to remind those to wear a mask. I did mine outside in the open air.
Also may want to consider doing only the front cat if your state (or province i guess) has strict emissions testing. I just got done putting my 89 corolla through emissions in MD and it had failed twice. When I took off the cat (original stock cat) it was totally hollow inside, nothing left at all. Put on a new one and retested and it fast passed in 30 seconds. Also quieted the exhaust down a bit (which is a good thing on this car, its too loud as it is). I noticed only a minimal power loss on it by going from gutted to new converter.
