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I have a 2000 bonny, 6 cyl. with a supercharger. My question is if i take off cat and leave it off, will it do any damage to engine. I would like to put some glass packs on it, maybe, depends on how a 6 cyl. would sound with them. I love the deep sound of a exhaust. I don't have an inspection in my state so that's no problem. Thank's dwight

Leave the cat alone, it's not hurting anything. Maybe swap it to a high-flow one for a deeper sound, and if you ever end up needing to register the car in a state with emissions testing.

IIRC, there are some exhaust clips around here.

Actually it is hurting my wallet. I get a code that says cat. sys. efficiency low bank 1, whatever that means. I kinda take it as maybe it's referring to o2 sensor. If that's the case i would rather buy a sensor than a converter. If it's the converter, i would rather take it off.

That is your O2 sensor, the one before the converter. Replace it.

Also, whether or not your state has inspections, it is illegal to remove and not replace your cat. converter.

You can get great sound from that car without removing it.

Replace your O2 sensor... that's generally what that code is.

However...

What will really hurt your wallet is the $2500 fine for driving without one. It's best just to replace the converter with a Magnaflow High-flow (cheaper option) or an OEM one (more costly).

Trust me, the police know if you run without a converter simply by smell and/or exhaust tone. Exhaust loudness/smell is enough to get pulled over and checked.... I've seen it happen.

Is that upstream or downstream. thank's

Upstream is the one you want to replace, the one in the rear exhaust manifold. The one behind the converter (downstream) rarely goes bad.

If you are getting the cat efficiency low code (P0420), that is the rear, or downstream sensor that throws that code. How many miles on your car? Has the front O2 ever been changed? If you're much over 50-60K miles, it would be a good time to change that, too.

The mostly likely cause for that code (if the cat hasn't been replaced) is a bad cat. Be responsible, and get the cat replaced, they really aren't that expensive. Get the high flow cat, then check the sound you get with that, and see how you like it.

Two pieces of bad information in this topic. You want to replace the REAR sensor, and it is not BEFORE the cat, it's after it.

It's a violation of federal law (all 50 states) to remove a cat from a car that was equipped with it from the factory regardless of whether your State/County/Parish has emissions testing or inspections). Any tire shop, mechanic, etc that sees no cat under your car can turn you in for a juicy little reward. Leave the cat, it's not hurting you.

just a few things to add...

1. ive had no cat on my car for 3 yrs now. and i DO have emissions tesing. and i DID pass with NO cat. and ive had my car at many shops(for new tires and to get balances and exhaust custom bent, other work is done by me) and no ones had a problem. maybe a few mentioned it, but as long as they didnt remove the cat themselves then they dont care.

2. if u do replace the cat. id get a factory replacement. i had a stainless 3" I/O high flow cat on my car shortly after i got it and it was rattling and blown out within a couple months. Boost eats cats.

3. if u decide to remove it. take it from me, it will be LOUD. and u will need an O2 simulator to tell ur PCM the cats there and working.... taking off my cat was a bigger difference then getting my headers, deleting my resonator, or replacing my mufflers during my full exhaust process. the cat is the biggest restriction and noise suppressor in the exhaust system. u will also lose some bottom end but gain top end.

it depends on the plans u have for the car. but as for right now, i agree with wren, leave it, its not hurting u. but if u plan to do lots of more mods, then it will benifit u. i'd say if u dont ever plan on going smaller then a 3.4 SC pulley with supporting mods then it prolly wont be benificial.

slickbonny, your emissions testing must just be hooking up the scanner and making sure the PCM is passing all of its self checks. The O2 sim will tell your PCM that everything is great. They obviously don't do a visual inspection.

Whether you've been busted yet or not isn't much peace of mind considering you could be at any time. Depends entirely on who sees it, and how much they know about the law and reward for turning you in.

I'd be nervous any time my car was on a rack for work that had less profit for the shop than the $250 reward if I had no Cat. There is an exhaust shop here in Corvallis that will leave your car up on the rack long enough to report you to the EPA before coming back down if you have no Cat. He will not work on your car if he finds the Cat missing, other than to replace it.

00Beast wrote:slickbonny, your emissions testing must just be hooking up the scanner and making sure the PCM is passing all of its self checks. The O2 sim will tell your PCM that everything is great. They obviously don't do a visual inspection.

yea i will admit, they are pretty dumb out here at Echeck. i made a testpipe with flanges and also a high flow cat with the same flanges so i could swap them in and out for echeck. but now that echeck is free i figured id go try without it. and no they did not look under my car with the mirror to see the cat(even tho i have the loudest Bonny ever, does not sound stock! lol). they just gas cap tesed me and looked for the SES light. but any1 with a tuner can take care of a SES light.

Whether you've been busted yet or not isn't much peace of mind considering you could be at any time. Depends entirely on who sees it, and how much they know about the law and reward for turning you in.

I'd be nervous any time my car was on a rack for work that had less profit for the shop than the $250 reward if I had no Cat. There is an exhaust shop here in Corvallis that will leave your car up on the rack long enough to report you to the EPA before coming back down if you have no Cat. He will not work on your car if he finds the Cat missing, other than to replace it.

i understand what your saying. for a normal, not car savy person, yes. but i work on my car myself. the only places that touch it are Walmart for tires and balances(they all kno me, the wheelchair kid with the loud Bonny, and my car goes on the short rack for just wheels). and the other shop is my buddies too. he does my custom bent exhaust and he puts the test pipe back on for me. so i dont really take any chances with shops ever.

the only thing that does cross my mind of possible is the cops. i get pulled over all the time(never had a speeding ticket). for no front plate, loud exhaust, running with just the fogs on, window tint etc...ive taken care of them all tho now. my plates attached under and behind the front bumb on that lip. my tint has been borderline legal and now they kno that im good. i keep my headlights on now always. and the 2 times for loud exhaust, they asked me wut i have and i told them SLP header and mufflers. then the cop says "oh my buddy has a T/A with those SLPs" and writes me a warning that says SLP "ok" on it. tells me to keep it and show any other cops if i got pulled over for it again.

plus, not gonna lie, i think my wheelchair helps. lol..

Magnaflow/Carsound 3" cat's are the cat's meow.

The other cheap 3" cats on ebay are known to burn out in under a year. I've seen this happen on 3 L67 cars locally.
The 3" Magnaflow's I and others have used are great and in over a dozen I know of in use on L67 cars I have yet to see one go bad, not to mention I've never heard of one going bad w/under 5+ years of use.

5 years of brutal abuse on the ZiLLA (running slightly to pig rich depending on RPM's, and I'm on year 5 on a Magnaflow.

willwren wrote:5 years of brutal abuse on the ZiLLA (running slightly to pig rich depending on RPM's, and I'm on year 5 on a Magnaflow.

I wish!! I replaced my cat with a high flow magnaflow, replaced both o2 sensors, cleaned the MAF sensor, and I still getting the old P0420 code.

I have read all the posts on here about it, and not sure what to do now. I am thinking maybe a new down pipe off the manifold. My gas mileage seems to be fine most of the time.

I guarantee it's the magnaflow cat that's still causing that code.

00Beast wrote:I guarantee it's the magnaflow cat that's still causing that code.

I am going to try and find a different high flow cat then. If that is what it is Beast, we are getting beers. SJU is only 15 mins from my house.

No, just have Randy (larz01, local member) delete the code. MUCH easier, especially since MN has no emissions testing.

One thing I noticed is that MAgnaflow now has the 46006 part number for the 2k+. That is what I am running and has never caused a code. If you look at their catalog, there is a different part number for the 99 and down.

I am just wondering, for those who have had code issues, if they are running the wrong one.

For MAgnaflow, use part number 46006 for a 2k or newer. You can get them for a pretty reasonable price if you search on line. My local shop charges $40 to weld them in, but I do my own now.