The new guy.......Exhaust Questions

[Jason97T/A]

Hey guys, I'm new here. I have a 97 TA with the dual cats. My catalytic converters have been shootin SES codes for a long time....even after my O2 sensors were replaced. I bought a pair of O2 sims and that seemed to take care of the problem. What I was wondering is how hard it would be to gut the catalytic converters since I have no use for them anyway now. They also seem to be bogging my car down a little. I would still like the Y-pipe to have the cats so it looks legal however. I live in Illinois and there are no emission checks so i dont have to worry bout that. What would it take to gut them and maybe run a straight pipe right through the converter? Any help is appreciated!
Thanks,
Jason

[Joe 1320]

We've been discussing this topic on another thread.......

http://www.f-body.com/forum.cgi/show...=&threadid=548

The solution is to have a person who is handy with welding, remove the cats from the pipes, the cats hollowed out and a pipe run through them. Then the cats are welded back to the Y pipe. Some guys just hollow the cats, but that doesn't do anything for WOT flow.

[Jeff_in_Atl]

This is just an FYI. It is illegal in all 50 states to even tamper with the converter.

http://www.exhaustsoundclips.com/epa_reg.html

I just read somewhere, I have been looking at exhaust systems too, that one of the companies tested a catalytic converter and the converter actually out flowed there muffler. Considering this, is it worth it to gut one. Not to sound like a greenie or anything but I wouldn't do it. The benefits don't seam to come near outweighing the benefits or the risks. Remember, the government can come in at any minute and pass a law requiring emissions. Then you would have to put it all back on exactly as the factory did it.

I put dual Accel cats and flowmasters on my 85 Mustang GT. The only thing that saved me is the federal law saying you can't even touch the converter even to replace it unless it was proven to be defective was passed in 1986 after my car was made.

[96TAragtop]

If emmissions aren't an issue, why not lose the cats all together, and replace with pipes? Id bet it'd cost >$100 at most muffler shops.

[wolfdogs]

Originally posted by 96TAragtop
If emmissions aren't an issue, why not lose the cats all together, and replace with pipes? Id bet it'd cost >$100 at most muffler shops.

im reporting you to the EPA.........you "airBuster" !!!!!!!!!














hahahahahahahahahah

[Jay 02 TA ws6]

Originally posted by 96TAragtop
If emmissions aren't an issue, why not lose the cats all together, and replace with pipes? Id bet it'd cost >$100 at most muffler shops.

That's what he wants to do...

Originally posted by Jason97T/A
I live in Illinois and there are no emission checks so i dont have to worry bout that. What would it take to gut them and maybe run a straight pipe right through the converter?

He just wants to be ""

[Jason97T/A]

Exhaust

Would a muffler shop replace my cats with straight pipe?

[Jason97T/A]

More Exhaust Questions

I do live in Illinois where there is no inspections but I would like to keep the cats on the y-pipe in case it does get checked somehow. Or do you think it really matters?? I've heard the penalties for not having them are extreme. Newayz, would my exhaust tone change after running a straight pipe through the cats? And isnt the drivers side cat curved a little and a pain to get too? I do have a Flowmaster American Thunder catback already. There is no point in keeping the malfunctioned cats on there is there? I need the cheapest and best method of getting rid of them.....any thoughts are appreciated.
Jason

[Joe 1320]

99% of the exhaust shops will not replace the converters with straight pipes. They are subjet to heavy fines. If you trailer in a race car and show that it is not driven on the street, many shops WILL work on the car, but they still will not remove the cats. The ultimate solution where the stealth look isn't an issue, an off road Y pipe with simple straight pipes where the cats normally reside would be the best. The gutting and rewelding of cats won't be done by an exhaust shop, they won't touch it. You have to find someone else, or at the very least, a shop that will do the work as long as the Y pipe (not the car) is brought to them seperately. Yes, the car will be louder. The cats by themselves are pretty good mufflers. I know several people who kept the cats, but ditched the mufflers. It sounds pretty good. If you are interested, I have an e-mail at home of a guy who hollowed out the cats and rewelded them. It looks stock and now he is selling the Y pipe. If you would like, I can foreward it to you later tonight when I get home. I think he wanted $100 plus shipping?

[Jay 02 TA ws6]

I'm not sure, but I doubt a muffler shop would just replace it with a straight pipe.

If there are no inspections, then as long as you have a "box", even if you have a straight pipe going through a dummy box, you should be fine.

Running a straight pipe would definitely change your exhaust tone -- probably the smell of the exhaust too.

If you are going to do this, you should do it on a lift anyways. I've heard headers, y-pipe and such is a difficult chore - you need to disconnect thte transmission to get to it. Anyways, plan on using a lift.

Don't keep malfunctioned cats on there. A muffler shop would put new cats on for you if you decide that's the way you want to go.

If I were you, knowing there are no technical inspections in your state, I would just run a straight pipe right through a "dummy box". Even if a cop pulls you over and gets under there to check, he'd probably be satisfied when he sees the boxes.

I hope that's a help.

[Joe 1320]

Originally posted by Jay 02 TA ws6
If you are going to do this, you should do it on a lift anyways. I've heard headers, y-pipe and such is a difficult chore - you need to disconnect thte transmission to get to it. Anyways, plan on using a lift.

It's not that hard. The hardest part is the removal of the factory exhaust bolts/studs. Y pipe removal is fairly easy, exhaust manifold removal is fairly easy as long as plenty of penetrant is used. I've done several conversions for friends all without a lift. I simply used ramps and/or jack and stands in my garage. The only parts removed for easier access were the alternator, starter and steering shaft. I've even done Hooker long tubes with no problems. It helped by jacking up the motor a little bit on one side, but was still pretty simple. In reality, the only snag I've seen is some headers don't use the same bolt holes as the factory manifolds an occationally you have to run a tap in the previously unused holes.

[Jason97T/A]

Went to the local performance exhaust shop.....

Hey guys, I went to the muffler shop and talked to the guy about it. Since there are no emission checks in Illinois he is going to just take the cats off and replace with straight pipe. There was even a town cop there why we were talkin bout it. He didnt care What are these dummy boxes you guys talk about? I dont understand what you mean. Do you think with the flowmaster system the car will sound good? He is only chargin me $45 for what he's doin. He said he could gut the passenger side cat but he wouldnt do the drivers side since its not straight. But he said it would sound better just with a straight pipe. What do you guys think?
Jason

[Joe 1320]

IMHO, you should have both sides done. It would not be wise to do only one cat and leave the other untouched. The motor will end up seeing different backpressure and most likely mixture problems from bank to bank. The computer may be able to compensate, but I wouldn't do it. Either all or nothing. You are also pretty darned lucky that a shop will even touch it on the car.

[Jason97T/A]

Originally posted by Joe 1320
IMHO, you should have both sides done. It would not be wise to do only one cat and leave the other untouched. The motor will end up seeing different backpressure and most likely mixture problems from bank to bank. The computer may be able to compensate, but I wouldn't do it. Either all or nothing. You are also pretty darned lucky that a shop will even touch it on the car.

I am having both sides replaced with straight pipe, he could have only gutted the passenger side he said though.....What are dummy boxes by the way?

[Joe 1320]

Originally posted by Jason97T/A
What are dummy boxes by the way?

A fabricated sheetmetal "box" that approximates the shape and the look of the cat, welded to the pipe. I haven't seen one of those that looked convincing. The best jobs I've seen were old, gutted cats where the shell was removed and rewelded to a straight pipe. From the outside, it looked like a perfectly good cat, yet when you look though the end of the pipe is was obviously a straight pipe.