I have been informed by 2 local mechanics that I should remove the catalytic converters from my 89formula or tey will be ruined in a very short time due to the performance modifications I have made to the motor. Please check Sig for mods. I just had to purchase 2 new CATCO CATS for my formula becuase I had failed emissions. Once I installed the new CATs, I passed with flying colors. The mechanics informed me that I am not thowing any codes at this time, so motor is working well.

Mechanics stated that with older OBD-11 system and newer mods to car, that I will ruin CATS and I will need to purchase new ones again in 2 years when emissions testing comes around again for me.

Do you all think I should leave the CATs on or take them off? I DO NOT want to have to re-buy CATs every 2 years. Has anyone heard of suchan issue before?

 

btt

 

The only way i could see you ruining your cats is if your car is running real rich. All the excess hydrocarbons and whatever else will eventually build up and clog it.... as to whether or not it will happen as quickly as two years, I cannot say. However, if its not that big of a hassle, I would say fab up some straight pipes w/ exhaust flanges and run those all time, then swap them out for the cats when u go for inspection.

 

Fast,

First, your '89 has an OBD-I system, not OBD-II.

(Strike 1 for the "mechanics"?)

Second, your original cats should have been the monolythic type, just like the replacements should be. Earlier cats were three-way cats and usually required a separate air injection supply to complete the conversion in the second stage of the catalyst bed. Depending on your modifications, the three-way cats may be insufficient to control HC and CO, but mono-bed cats do a much better job.

(Strike 2 for the "mechanics"?)

Next, it is illegal for a service organization to remove an emissions control device from a street licensed vehicle for any purpose other than testing. If the car entered the service bay with parts missing, they can still work on it, but they cannot remove anything more. They'd could get a vacation in the federal "graybar hotel" for not complying, but usually only get fined enough to put them out of business. Advising someone to remove an emissions control device from a street vehicle may not be illegal, but is certainly on the borderline, and not within the spirit of the law.

(Strike 3 for the "mechanics"? Maybe a ball...maybe. )

Finally, instead of removing the cats, ask them why they cannot tune your engine to run WITH them. Newer cars make a lot more power and still run cats. Are they in over their heads?

(Called Strike 3 for the "mechanics" - they weren't even swinging.)

 

Hmmm....
Think about how cats work....
The element (core) absorbs heat from the exhaust system
and from a chemical reaction between the platinum and the
exhausts gases.

Once sufficiently heated say 1200 to 1400 degrees it promotes
further burning of exhaust gases primarily HC and CO.

A second element I think Rhodium acts in much the same way
but is purpose built to strip oxygen from nitrogen dioxide
and nitrogen monoxide. These are created when combustion
temperatures exceed 2600 degrees.

Sooo...
At about 1800 degrees the substrates of many cats starts to
melt. How do you get there... Usually a combination of willfully
running too rich, failing oxygen sensors and or oil contamination.

The thing to consider with the mods that you have is are you
doing anything to closed loop operation that would encourage
the car to run rich. Further do you have an ongoing malfunction
such as leaky seals that puts oil into the exhaust system or
old and malfunctioning oxygen sensors.

Last but not least ... 14.7:1 is not absoloutely the best afr for
power production, a lot of folks will try to get somewhere near
13.5:1 at WOT. Unfortunately a lot of folks don't get even close
and run way richer ...

This is mostly not a big problem as WOT runs are relatively
short (seconds) and relatively few and far between for
all but race cars.

Now before you feel relieved or anything... what your mchanic said has a grain of truth. Running rich for say 15 to 20 minutes
is long enough to build enough heat to "toast" the cats. The good
news is they won't typically melt any sooner.

Soooo...
It seems to me based on what you are doing that you are not an idiot. I'd say it is time for a visit to your friendly local dyno shop
(one that has a wide band 02 sensor) and have a look at what your configuration is doing. From strictly a hot rodding point of
view it will be "huge" in terms of sorting out the stupid stuff
and plotting what you should do next. Things like optimum
timing, optimum fuel pressure etc.

Also you will find that "in general" the more power you make
by getting it "right on" will almost in every case result in lower
emmisions. The exception being highly optimized engines
(ones that are near f***ing perfect)

 

I was told that here in CA cat can be changed for emissions AND/OR if you have 50k + miles on your car. Does anyone know if this is true??

Brian

 

Awesome. Thank you all for the suggestions. One thing as well. I made all these mods to the car becuase when I acquired the car I was getting the "blue Puff of smoke" syndrom when it first started up. This could of been the death of the original set of CATS I had on the car due to the additional oil through the exhaust. That could of been why my CATS were in such disarray. I am starting to fell more comfortable about putting the CATS back on now. I currently have custom pipes in place of the CATS, but I am running into some exhaust rattling noises that I believe are coming from the Flowmaster. I think with the CATS out, the muffler cannot seem to handle the additional "free flowing" of air through it. I get a metal sounding rattle like I have a little demon in there with a piece of steel hitting on the muffler inside.

I would prefer to put the CATS back on if possible, so I think I will head to a lcal dyno and get it tested and tuned for accuracy purposes.

 

Changed, but not removed. What Vader is talking about is permanent removal, cant do that.

The 50k miles/emissions purposes for replacing a cat in CA is a huge gray area. I've never seen or heard of someone getting busted for dropping in a high flow cat the day after a car was bought, they just want a cat on the car.

 

The reason for the blue puff of smoke from the exhaust on startup has nothing to do with the cats, but the valve seals on the heads. They dry out after a while, and let oil leak overnight into the cylinders, so when you start up the car that oil gets burned.

 

Chevy83z28: I understand that and thanks for telling me but I was talking specifically about that oil in the exhaust possibly adding to the demise of the CAT in the car. I have heard that oil can destroy a CAT over time if it keeps occuring.

 

Sorry for the misunderstanding then. Is that really true that the oil will ruin a cat? I'd think that from the tiny bit you were getting on startup wouldn't be enough to kill it (you'd have to be burning a lot more oil for it to make a big difference...) at least that makes the most sense to me (?)

 

I believe that's a federal law, not just a california law. The original cat has to be on the car unless it's broken or damaged, or if you exceed a certain mileage. You're supposed to retain the broken/damaged/old cat for a few months, in case you're called out to court because of the swap. I think it's more for garage mechanics to leave a "paper trail" for. My original cat was gutted, I replaced it with a high flow one. Now who's to say I didn't buy the car with it already on? Or that I didn't put it on years ago?

 

I basically said what Vader said when you asked on the exhaust board. Well, ok, not exactly, but like said high performance cars today use cats. And like I said in another post the TT Lingenfelter uses them too. If that car can, any car can.:hail:

 

Mark: My concern is that the Lingenfelter vette is much newer than my 1989 Formula which uses an OBD-1 system for emissions. The newer vette uses a much newer emissions standard that probably runs much cleaner. I am somewhat convinced at this point in time that I can put my CATs back on y vehicle, but not totally. I know that the mechanic has informed me that I am not getting any codes at this time so I would suspect that I can put the CATs back on and be safe from destroying them. Its just that I need to rely on others opinions and I am not getting clear statements that say I can put them back on without damage in the future.

Does that make sense?

 

Hmmm...
1. Put the cats back on.

2. Check the afr across a range of operating conditions with
an wideband 02 sensor.

3. See if you can get the attention of the barmaid :-)

 

Wanted to let all you thirdgenners know that I went with your recommendation and put the CATs back on my car last night. We will see if they last or not in 2 years when i need to go through emissions again.

Also since I put the CATs back on the car, the metal rattle noise has gone away. The resonance from the CATs must of made the Flowmaster perform the way it is supposed to. It runs much quieter now.....Like a sleeping demon......The sleeper know one will know about. :-)

thanks for all your correspondence on this matter.
FAST89

 

Fast,

It would still be a very good idea to check your operating mixture as urbman recommended. It may save you some problems, and not just with the cats. Running excessively rich all the time can burn out a cat, but will also tend to carbon up the chambers and valves. This will eventually cost you performance, and your fuel mileage will suffer all the while. Running excessively lean can destroy piston tops, valves, and heads, and well as tending to overheat and promote detonation. You really want to be in that "ideal" range for normal operation. As for WOT power, adjust for whatever ratio you want. Unless you're running at Bonneville or the 10-mile university test track in Kentucky for 20 minutes at a time, the duration shouldn't be long eenough to cause any problems.

As for the oil issue, oil burning in the cat is a bad thing, but oil coating the cat is a really bad thing. The puff of smoke experienced by many of us on cold startup (the BowTie salute) is inconsequential in terms of damaging the cat converter(s). The oil that is burned has collected in the cylinders and intake ports, not in the cat. And that oil is burned generally within the cylinders, and not the cat. The volume of oil from customary valve seal leakage is so small that it shouldn't be an issue in terms of the cat(s). What can be a larger problem is constant oil consumption from worn valve guides and rings. A constant stream of oil vapor, burned or not, to the cat can coat the substrate and elevate cat temperatures, or spoil the catalyzing reactions and render the cat useless. Then again, if you're using enough oil from bad rings or guides (like all those clapped-out, "environmentally friendly" Mitsubishis), emission control probably isn't a real priority for you. That's why there are federal standards and emissions tests. If your car is burning that much oil, it SHOULD be off the road.

Let's not even get started on diesel engines....

 

VAder, if I do find that I am still running rich, what would be the next steps in combating that problem?

I have an Ed Wright fastchip that was burned specifically for the stock injectors that I am running....where would I tend to lean out conditions if I were running rich?

FAST89