Just looking for some opinions here. A friend of mine with a 69' Pontiac Beaumont (Canadian Pontiac Chevelle...) put a pair of cat converters on his car this fall. I was kind of scratching my head as to why he would put restrictive emmissions crap on his muscle car. He told me that he used a performance cat converter, and there really is no loss in power. What he did say was that he no longer gets the stink from the tail pipes, that says this car has no emissions.

Well after running the car in the garage on Friday I came in and my wife said I stink! It was the fumes from the car. Anyway I got some money for Christmas, and for about $100.00 I was thinking of getting these and putting them on my 72' Cutlass this spring.

Does anyone else run these? What are the thoughts? Thanks, and Happy Holidays!

Joe

 

New cats tend to give off a funky smell, that is probably what your wife smelled. There are performance cats that hinder perfromance very little. I am not sure what the results would be on pre '75 vehicles, though I am curious as to what emission reductions that there might be.

 

i think what joe is saying is that he doesnt have Cats on there and is thinking about getting them installed and wants peoples opinions. I heard the same thing about Cats not really being performance limiting anymore as well but i wont run them on my 69 for the reason it didnt come with them lol. But if it makes the wife happy....(no married just saying)

 

You're out of your mind.

Sure a (relatively) non-restrictive cat will probably reduce emissions somewhat, and thus alter the quintessential odor of your '72 classic to some degree, but it will not be properly set up, the cats may not be able to reach their proper operating temperature, you may need to re-jet your carb for optimal performanace of both the car and the cats, and, in general, you are spending money to add unneccessary things to your car, thus violating the age-old dictum of "If it ain't broke, don't fix it."

- Eric

 

Not that I'm an expert on emmissions, I did try to pay attention when things changed.
In 71 + 72, they reduced compression to start reduction of CO.
In 73 + 74, they leaned carbs. and 195 thermostats for a 'cleaner burn'.
75 + up - catalitic converters - 1st the pellet type - then on to the honeycomb, which seem to be the best and least restrictive!
To install a converter on a car not set-up for it, IMO, woud be a waste of money.
The performance loss woud be minute at the beginning, but as they clogged up, progressivly worse.
And BIG loss of MPG!
To what gain???? Idle quality in the garage?? Put a hose on it!!

 

I can't see any benefit of putting cats on a car that does not require them for emissions inspection.

If you've got rich smell, your tune is off. Either yer carb is jetted too big, yer idle mixture is off, or the carb needs rebuilt.You put a cat on an engine like that, it will soon foul and won't do any good at all.

Modern fuel formulae don't help either. Modern gas just stinks.

 

In modern cars....anyhow....Catalytic converters work this way. The ECM cycles the engine between rich and lean via feedback from the O2 sensors. Rich feeds a little extra fuel to heat up the cat to keep it in operating temp....i.e. it actually becomes a 'combustion chamber'of sorts.... and with that heat in the lean cycle it cleans the exhaust.

Since carbs tend to always run a motor in a rich mode, you're just feeding fuel (and probably too much for the cat to sustain) and will end up fouling it out. For instance a fuel injected motor thats running to rich will destroy the cats.

You're friend has just wasted a bunch of money....period.

 

Thanks for all the input and advice. This idea is officially dead. I talked my friend Randy who set the engine up for me with the timing and carb set up. He said he is not done dialing everything, and to not go with the cats. Once he gets her tuned she won't smell like she is running rich.