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There are no emission laws where I live, so I was considering removing the stock catalytic converter on my 1994 SSEi and my question are:

Will I notice a substantial power gain?

Is it worth removing?

What would you do if you were me?


My car is stock, but I plan on getting a cold air intake in the future and leaving the resonator on.


EDIT

There is some power to gain. But you'll gain a lot more raspy sound too. 3800's have enough of that to begin with. A high flow universal cat is a better option, IMO. Uncorks the exhaust a good bit while keeping the rasp at bay.

It's breaking a federal law here in the States to remove a catalyst. If you ever take your car in to a shop to get some work done, a broke tech may spot the test pipe and turn you into the EPA for the bounty. Then you'd be hit with lots of $$$ in fines.

Better to get a high-flow cat, or leave the stocker.

I imagine that there would be a power gain but the raspy sound? Isn't that what the resonator is for?

EDIT

True, but like I said it is not required to smog cars in my county....so as long as I am within my county limits I am not breaking any laws and I would never have a reason to go to a repair shop being that I can do most of the work myself.

EDIT

I've ran my '95 SSEi in the past without a cat. I wouldn't recommend it to anyone. The power gains were minimal and the noise was a lot louder and raspier than I hoped. I did do a full exhaust system upgrade at the time, so there may have been other factors, but I believe that to be the biggest towards the negative sounds.

Out of curiosity, where are you located?

It may not be required in your county. But say you're on a trip 200 miles from home and your brakes go out (been there, it was 800 miles from home, needed the car the next day). While on the lift the tech notices your car doesn't have a cat. Mucho $$$.

High-flow kitty. Then it's explainable, and you're legal.

Keep a Cat on it... It will take a lot for you to outflow it to begin with.. If the cat on your car is original you may be starting to plug up and this might be starting to hurt performance...

I have Magnaflow High flow's on my 95 Bonneville and 95 Trans Sport... Neither one of them have any issue spinning to 6200...

Regardless of local emissions testing, removing them is illegal. There might be an age or year that it is legal, but I don't know what it is.

I've got a Magnaflow cat and muffler on my 92. The startup and idle sound is really good, IMO. But it needs a resonator for higher RPM's. 92's didn't have a stock one.

It's a Federal LAW that you must keep the cat. It has nothing to do with what's tested where. All 50 States require it, and whoever turns you in gets a nice little sum from the EPA, and you get fined.

You will likely feel a loss of low-end torque and the exhuast will sound like crap. It takes quite a bit of power-adding to outflow the cat. Get a high-flow Carsound or Magnaflow (both made by Magnaflow) online and put it in. You stay legal, gain flow, and don't lose the bottom end the Series 1 L67 is known for.

Nye county, Nevada

EDIT

So the resonator and muffler don't provide sufficient back pressure alone?

My car has 118,000 miles and runs great (does burnouts with no trouble).

At what mileage do these stock cats clog substantially ?

I would think three obstructions in an exhaust system would be somewhat restricting but you guys are the Bonneville experts

EDIT

If you can still do that and it runs good then there really isn't anything to be gained... The exhaust system on the H Bodies are pretty good and in the majority of cases we won't be able to outflow it anyhow...

If your car is doing that good you might just leave it well enough alone... The resonator really doesn't hurt performance on these cars, the Muffler if you were to replace it wouldn't do much more than change the sound...

On my 95 Bonneville at 145k or so the converter was starting to plug up.. I replaced it and noticed the difference right away.. 16k later the motor told me the truth... The old converter plugged due to the motor burning oil...

On another 97 SSE one of the members yanked the converter to have a look... It was in such good shape that we put it back as there was nothing to be gained...

I would at the least stick with a converter.. For your car 2.5 in and 2.5 out High Flow... If you wanted more sound you could do a Magnaflow Muffler or Flowmaster among a few others that have been used...

On my 95 Bonneville I am going to add toys to it, Cam included... about the only thing I will change on the exhaust from its current set up is going to be the Muffler... I want Dual outlets with a bit more groan...

I was wondering if the catalytic converter being faulty causes the car to stall?
I have only recently had the problem and it stalled once, I drove my way home from work, it's a 18 mile commute. I have not had problems with it stalling before this. I drove home, it is 65 mph from work to home, and about a quarter mile from my house, it stalled. The AC was working, the electronics were working, radio worked, etc. The only thing it stalled and the dash said "check gauges". There was no indicator on the dash that there was anything wrong, all levels (temp, voltage, oil pressure) etc, were reading normal. I turned the car over and it started fine, but would only stay running for about 3 seconds. It only happened once, I let the car sit for about 4 hours and tried it again. It started up just fine and it will run just fine for a certain amount of time. I haven't driven it since. I had someone come and look at the car, he looked it over, tried running it and everything, he said it is the catalytic converter. I asked about the fuel filter and fuel pump because that is another thing I was told (by my dad) that may be wrong with it, but he said he can hear the fuel pump working and he doubts that was the problem.

I haven't been able to find anyone else to come look at it, and I wanted some advice before I invest in a $100 part, I really can't afford to waste $100 on a part that I may or may not need.

Thank you.