Adding Catalytic Convertors to the Old Girl...

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Dart Sport 360

Dart Sport 360

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Hi,

I'm thinking of adding a set of cats to my Dart to reduce or eliminate the exhaust smell...

Does anyone have any advise or experience with this. Carb fed 360.... I don't want to choke out a bunch of horsepower but I know there are better cats out there that should work.

Thanks for your input!
 
I would think its not a good idea. If the engine has had anything done to it where it is beyond stock, I would think that the cats would run way hot,Even if it's at a stock level. Gotta remember they are there to help "burn off" residual fuel. They may even get hot enough to cause a fire. One of the big three had issues with cats in the early to mid 80's being hot. Most vehicles that were carbureted had some type of system to lean it out. Just my thoughts.
 
Dart Sport 360 said:
Hi,

I'm thinking of adding a set of cats to my Dart to reduce or eliminate the exhaust smell...

Does anyone have any advise or experience with this. Carb fed 360.... I don't want to choke out a bunch of horsepower but I know there are better cats out there that should work.

Thanks for your input!
Click to expand...

Before you throw catalytic converters, at it : I would install a wideband O2 sensor, first. ( If you install cats, you will need it anyway ( tune it ...). Just my thoughts.
 
The cats probably won't solve your exhaust smell issue and could easily cause a serious issue with getting too hot possibly being unsafe.
 
I smelled a old chevy truck going by, 4 houses away. that thing stunk of raw fuel in a way that I thought was not possible. If you can tune the carb, there will be no noticeable smell. Its very easy to see with a wideband, narrow band not so much but even a narrow band will get you stoich at idle. 1/8 turn of the metering screw can be the difference between a stinky exhaust and a 'clean' exhaust. Cats run hot, so hot that some had shields under them to prevent brush fires. They make high flow cats but without the supporting hardware, I dont think they would be worth it. You can run a pulse injection setup into the exhaust manifold like my mazda. Its just a beveled pipe in the exhaust manifold that is open to air cleaner air, and it flows through a big rubber flap one way valve so a backfire wont blow your air cleaner lid off. It provides the exhaust with O2 so it can burn off unburned hydrocarbons in the manifold. A.I.R rail off a later 360 will do the same, and look cleaner too, no smog pump needed, just run through the check valve.
 
It won't stop the smell, and most carb running motors run rich enough to take out a cat in a very short time. You can buy stuff to put in your fuel to make it smell pretty, like cherry, bubble gum, etc. Expensive, but cool at a car show.
 
Thanks for the input guys. I don't think the smell is that bad and only worse when stopped at a light for a long time.

The wife complains about it but who wants to ride with her anyway.

I agree the carb could probably be leaned out a bit but at the track the plugs look good. Probably the idle screws.

I figured someone here would have the same issue and have figured out a fix. I was told that the smell is the ethanol that's in the fuel these days.

Adding perfumes to the fuel just seems wrong... something a ricer or ford guy would do.
 
maybe have a look at your trunk and door seals as well as the body plugs. even pinholes in the floor boards and trunk will let fumes in
 
If your plugs look good after a flogging at the drag strip you may want to try a heat range or two hotter on the street. I had a rich exhaust and a slight engine miss with mine and 2 heat ranges hotter plug cleaned it right up. tmm
 
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