I was coming back from the Edmonton Grand Prix, about 5 hours away. When I pulled into the garage and opened the car door, I noticed a lot of heat coming out from under the car.
First thought was that the Cat was gone. The next day, I took it to a muffler shop. They banged on it and because it ratled, they said it was shot.
They quoted me CD$500.00 for a new one installed.
I went to GM, and they quoted $1,100.00 (just for the part) but they are not availlable. You would think for that price, they would make a special order one just for me
I then checked one of the Vette "specialty" mail order (I think it was Hecklers) and I can get one for US$140, or about CD$165.00
This is for the main cat. It is the only one on my car.
My questions are:
Will a cat really tell me if it is done, or should they have done a pressure test?
How can some be $1,100 while others are $165????
If I buy the cheap one, will it fit, or will I have to do any cutting?
Are "freeflow" cats much louder than regular ones?
And before anyone suggest it, I have no intention on just taking the cat out because it would be way to loud and a certain Forum member would flame me
Thanks for any info.
Fred

 

the cat comes off real easy
Ecklers has them along with other part stores
jetracing.com/motorsports/classic/classic.html

Then you can look inside to see if it melted

Don't get an original one at that price you would be nuts
The replacement one will work fine

If you melted it it is probably from another problem you have with the car.
check the Oxygen sensor

Cats melt when to much raw fuel enters them
A chemical reaction takes place to clean up the pollution.
But when there is to much it gets hot them melts to a ball of hard metal. If you poured raw gas into one it will burn or start on fire with no matches.

I had a Plymouth with the lean burn system and was on the highway.
The cars ignition failed while i was going 70 mph
It was a carburated engine with an electronic control.
So i was pumping the pedal while the engine was spinning still to try to get it powered up again. Big mistake because it punped raw fuel into the convertor. The floorboard started to get real hot so i pulled over.
The convertor was beyond the red hot color and was accually white hot. It looked like a blast furnace and maybe even hotter. I say it got up to 2,000 degrees.

I was lucky it happened in the winter and there was snow to throw on it
A half hour later it cooled down the car statrted and I was able to drive it home while it rattled. When i took it off the platinum mesh screen inside was melted into a ball. That ball will then clog the output hole and create to much back pressure if left in there.

So you need to replace it.
Make sure you find out why the car is dumping raw fuel or runnning to rich making it melt or you will go through another one.

 

I bought an aftermarket cat for my 87 last year from MAM. It is the same laying legth as the original, but the active portion is smaller. Considering the car passed emissions testing the month before and it only had a sliver of catalyst bed left in it, my guess is the new one will work fine. Compared to the old worn out one, it is quieter.

I had three issues with the aftermarket converter:

First the air pump tube does not fit up the same way. It requires a hose that is sold separately, and it isn't highlighted as such in the catalog. So ask when you order.

Second, the OEM converter had a threaded flange at the rear and the aftermarket unit had plain holes. I had to find longer bolts and a couple of nuts in a hurry.

Third, the ID/OD fit up to the front y-pipe is sloppy and could not be crushed to fit with the clamp (oh yeah, buy a new clamp). I am still working on getting a good seal at this joint. Ultimate copper sealant worked for a few months, but eventually it blew out.

Hope this helps you to shop and prepare.

 

I put a random tech high flow cat on my 86' when I installed LT headers a few months ago.

There was a noticable (and welcome) increase in sound, but the mufflers are stock so it isn't loud, just present(before it was like driving a Camry). For a daily driver I think it is a good balance.

 

Great, thanks for the responses.

JetSet,
No intentions on putting an $1100 cat on the car. I was just wondering why the huge dif. in prices.
Now, you really have me wondering why it failled. The cat was off the car last winter and it looked fine then. I ran it at an autox a couple of weeks ago and no problems. Going to Edmonton, everything seemed fine, coming back, I took it easy because it was raining, but I did buy a tank of regular because that is all they had. No other stations for over 60 miles. (Really, I am not kidding)
The service engine soon light is on, but it always is on whenever I go on the highway. Always been like that since I've owned the car. (4years). If I put the stock chip back in, no light, if I put the Hypertech one on, light comes on the highway. I dont thing it is related. (yes, I know, most of you dont like Hyper"crap", but I think it does make a dif. on my 86.)

Rich,
Thanks for the pointers. It will help a lot.

Square,
I am wondering how much of your noise increase was from the headers and how much from the cat. In my case, I have Ultra muflers, and they are loud, so I would not want to increase the noise level at all.

If anyone as sugestions on why the cat failled, please pass them on.
BTW. no black smoke out the exaust, starts really good cold, sometime, I have to crank it for 5-10 seconds when it is warm.
I do get a bit of blue when it first start, (valve guides?), but zero oil consumption between changes.
Thanks
Fred

 

You can have my cat. It was 2 years old when i removed it. I cut the both ends off to use the flange for my "test pipe" but there is enough left on the ends to weld your flange on.
Your cost is shipping only

 

Thank you very much. I sure was not expecting that.
I'll send you a PM.
Thanks again.
Fred

 

Glad i could help