Catalytic converter

[72CudaROG]

Hey Guys,

Sad topic..

My wife is tired of the fummy smell, even driving with windows down the fumes come inside the cabin.

I checked all holes in trunk area, made sure my gas tank vent was working right. But honestly is just a very strong smell.. I mean it’s a 440.


Was thinking about installing this high flow Cat on a flange and mount it directly to my header, anyone running high flow cat?

Curious to see how much noise reduction there is/smell reduction.

3" Magnaflow Universal 59959 Catalytic Converter High Flow Spun Metallic Cat | eBay

Part # 59959. Converter style: Universal fit. This is a high flow performance catalytic converter. Magnaflow/Carsound Universal Catalytic Converters. UNIVERSAL COVERAGE CHART. We carry 2", 2.25", 2.5" and 3".

www.ebay.com

 

[moparleo]

Catalytic convertors don't work with a standard carburetor setup.
You need to run an O2 sensor which requires a computer and fuel injection.
You need to fix your exhaust/fuel problem.
Has it always done this or have you made any recent changes to your car ?
Read this article and if you convert your fuel system to work with a convertor, remember to install HD heat shieling between the floor and the convertor. Early carbureted cars would catch fire because of the extreme heat generated by the convertor.

Catalytic Converters

Catalytic Converters Function and Diagnosis

www.restore-an-old-car.com

 

[72CudaROG]

Catalytic convertors don't work with a standard carburetor setup.
You need to run an O2 sensor which requires a computer and fuel injection.
You need to fix your exhaust/fuel problem.
Has it always done this or have you made any recent changes to your car ?
Read this article and if you convert your fuel system to work with a convertor, remember to install HD heat shieling between the floor and the convertor. Early carbureted cars would catch fire because of the extreme heat generated by the convertor.

Catalytic Converters

Catalytic Converters Function and Diagnosis

www.restore-an-old-car.com

Really…

Was unaware of this. So I have a charger with a 408 stroker + sniper efi. Would a set up like this work?


So you wouldn’t recommend me putting this high flow cat on my 440 cuda with standard elderblock 750cfm carb?

 

[72CudaROG]

Catalytic convertors don't work with a standard carburetor setup.
You need to run an O2 sensor which requires a computer and fuel injection.
You need to fix your exhaust/fuel problem.
Has it always done this or have you made any recent changes to your car ?
Read this article and if you convert your fuel system to work with a convertor, remember to install HD heat shieling between the floor and the convertor. Early carbureted cars would catch fire because of the extreme heat generated by the convertor.

Catalytic Converters

Catalytic Converters Function and Diagnosis

www.restore-an-old-car.com

I havnt done any changes.. it has always been very very fummy

 

[fasjac]

I havnt done any changes.. it has always been very very fummy

It’s just a hot rod that may need some tuning. And that may not do it completely.
If it’s that fuely smelling in the car with the windows down, sounds like something isn’t right as Leo said.
When I had my six pack to rich, you would need to change clothes after being around it. But, never inside the car driving.

 

[Chryco Psycho]

IMO the Eddy carbs are the hardest to properly tune due to a total lack of adjustable circuits , the specific cam used can be a big problem as well .

 

[70chall440]

Think about it this way, back in the day we didn't inhale gas fumes every time we drove our cars, there is no reason why you are now except that something is wrong and if I had to guess you have a header leak somewhere near the passenger compartment (at the heads or at the collector). It might be small but its enough. The fumes are getting into the car most likely from your vent system which means fumes are collecting under your hood and being sucked into the car.

I just drove a 70 Satellite today with a 440 with a fitech EFI system, big headers, etc. Standing behind the car it was very smelly but inside the car it was fine (windows up or down).

This is an exhaust system problem.

 

[72CudaROG]

Yeah it’s pretty strong fume smell just standing besides the car, and obviously behind it.

I looked at the headers I couldn’t find any pinholes or anything like that. Headers are nearly new.

So I can’t put a catalytic converter on with my carburetor? I know I might need to re tune it afterwards.

 

[70chall440]

Actually there isn't any reason you cannot put one on your car but as Leo pointed out, you have to take a lot of precautions to protect the bottom of the car as they get stupid hot. Additionally, as Leo pointed out, you will need to tune the car to address the addition of the converter.

My (and others) point is that you are thinking that this converter is going to solve your problem when in fact it might actually make it worse by creating back pressure in the exhaust (pre converter) which is going to make its way into the car however it is getting in there now.

Look, there are several things at play here. First is whether the car is running too rich or not. This needs to be be figured out first and foremost. Second how this exhaust smell is getting into the passenger compartment especially when you are driving. Do you have full tail pipes? If you have turn downs under the car that a part of your problem, however if you have full tail pipes there is some other issue. If the exhaust system was sealed as it is supposed to be the exhaust would exit out the back of the car only. Hundreds of thousands of cars have been on the road for decades prior to application of converters that did not have this problem.

I am not saying the headers have a hole in them, I am saying the gasketed surfaces are not sealed.

 

[72CudaROG]

Actually there isn't any reason you cannot put one on your car but as Leo pointed out, you have to take a lot of precautions to protect the bottom of the car as they get stupid hot. Additionally, as Leo pointed out, you will need to tune the car to address the addition of the converter.

My (and others) point is that you are thinking that this converter is going to solve your problem when in fact it might actually make it worse by creating back pressure in the exhaust (pre converter) which is going to make its way into the car however it is getting in there now.

Look, there are several things at play here. First is whether the car is running too rich or not. This needs to be be figured out first and foremost. Second how this exhaust smell is getting into the passenger compartment especially when you are driving. Do you have full tail pipes? If you have turn downs under the car that a part of your problem, however if you have full tail pipes there is some other issue. If the exhaust system was sealed as it is supposed to be the exhaust would exit out the back of the car only. Hundreds of thousands of cars have been on the road for decades prior to application of converters that did not have this problem.

I am not saying the headers have a hole in them, I am saying the gasketed surfaces are not sealed.

 

[72CudaROG]

Thanks for all the great information. I will check my tune again, but have had this problem for so long and even right after tubing.

I agree I think their must be an exhaust leak somewhere.. it’s a full exhaust with pipes exiting out the rear of the rear valence.

I’ll check all the gaskets and see if any of them are cracked or worn out.

I’d just really like to be able to cruise with the windows down and not have my shirt smelling like gas haha.

 

[moparleo]

You need to have someone with a gas analyzer, ( basically a smog machine) do the tune up. This way they can dial in the a/f ratio and tune it for minimum emissions at the same time.

 

[Challenger RTA]

My first thought was.Do you like spending money? fix the exhaust leak your wife will be happy.What about you?

 

[Challenger RTA]

Tell her to roll the windows up and go faster!

 

[heminut]

I had problems with a gas smell in my Cuda, well my wife did, I can't smell. Turned out my 750 Edelbrock carb was the culprit, my floats were set too high and because of that the engine was sucking extra fuel out through the boosters. I set the floats to the correct level and my wife says the gas smell is gone. The car was also getting 11 mpg on the highway, which was way to low for the setup I have. I haven't checked the mileage since I got the carb sorted out, but I'm sure it will be much better.