catalytic converter on 1973 roadrunner

[rdrunning]

I know this sounds crazy, but the exhaust stinks. To the point that it takes the enjoyment out of driving it, i don't like going for a 10 minute cruse and wanting to puke when i get home. Its a big block basically stock, a little larger cam and edelbrock carb that has been tuned. This isn't a tuning problem, the car runs good it just smells. I am wanting to put two high flow cats on it. I can get them pretty cheap and weld them in myself. I am not that worried about performance, after all its a basically stock smog motor.

i am looking at the metal core high flow cats, not the ceramic (ceramic is more prone to melt down).

anybody done this? thoughts?

 

[Hemi Rebel]

If it smells inside you have an exhaust leak and fumes are entering the car. Even tuned poorly all the stink should go out the back

 

[Longroof]

Maybe I'm getting old and don't remember as well as I used to.... but Cat's didn't come out until the mid 70's.... even here in California. ... I really doubt you need them for emissions.... I k ow you would not need them in California where the smog laws are pretty strict.

 

[rdrunning]

the tail pipes are run out past the rear bumper, but when your sitting in traffic you still get a good bit of exhaust.

its not for emission purposes, just personal preference

 

[Cranky]

If you think the cats will make it smeeeeel better, then throw em on it. I think cats make a car stink especially when they piss in it so I try and keep them out . Seriously, I really don't like the way cat exhaust smells and I'm thinking that you do have a leak. Are you getting any fumes coming in while driving? A bad trunk seal or even sheet metal plugs missing will suck it in while moving and especially so if you have a window open. I run straights on most of my junk and even the modern junk has straights and to me, it doesn't smell inside even while sitting at a light with the wind at my back. Are you sure it's as well tuned as you think? How many miles are on the engine? Does it have some blow by at idle? PCV not working like it should. Now blow by stinks like hell to me.....

 

[Badvert65]

Maybe I'm getting old and don't remember as well as I used to.... but Cat's didn't come out until the mid 70's.... even here in California. ... I really doubt you need them for emissions.... I k ow you would not need them in California where the smog laws are pretty strict.

He's right. Cats weren't started until 1976 and even then, not every car had them (most did). By 1978, all production cars and most light trucks had them, I think 1979, everything had to have cats.
1973, not so much.

 

[kb67mopar]

Cats won't make it smell better...probably more like rotten eggs. The richer the fuel ratio the more rotten egg smell you will get. Honestly I think these guys are right, you probably have a leak somewhere bringing it into the car.

 

[rdrunning]

humm, maybe it isn't tuned as well as i thought, the pcv isn't hooked up, its just venting out of the valve covers under the hood. there is a decent amount of blow by coming out of them too. maybe its time to hook a legit pcv system back up.

 

[Cranky]

humm, maybe it isn't tuned as well as i thought, the pcv isn't hooked up, its just venting out of the valve covers under the hood. there is a decent amount of blow by coming out of them too. maybe its time to hook a legit pcv system back up.

I'm betting all I have that that is your problem! Now that sheeet stinks!!

 

[Hemi Rebel]

I'm betting all I have that that is your problem! Now that sheeet stinks!!

Lets not get crazy now. You dont know nothing about how this car is set up

 

[Cranky]

Lets not get crazy now. You dont know nothing about how this car is set up

Get crazy? Been that way for a long time now He said it's basically a stock engine.....but yeah, other than that, I k no nutin.

 

[Longroof]

Why would you want to run cats? Sorry but I'm still stuck on this. I would take those POS things off and never look back....

 

[rdrunning]

cranky,it stinks!

the new generation, high-flow cats are not nearly as restrictive as the 70's/80's cats were.

most modern cats flow more than chambered mufflers

 

[slepr1]

I was thinking of putting cats on both my cars. I spoke to a muscle car garage about the exhaust smell and he highly recommended putting hi flow cats to cut the smell. He said their are various types that will cut the smell at various levels. Obviously the more expensive, the more it reduces the smell. He showed me a couple different designs and both looked like ceramic, but could be mistaken. He said todays gas is formulated much differently than earlier days and the smell proves it. After checking all the above mentioned suggestions, this could help. Btw, after putting EFI on m 71 Cuda the gas smell went down 70%.

 

[WP29440SE]

definitely a leaky compartment issue, unless you drive around with your window open all the time. I just replaced all my door seals, trunk seal, and sealed every existing hole inside the car that didn't have a use. my exhaust dumps before the axle , and I cant smell a thing other than the new seat covers. . .. and my car runs rich

cats are for dogs ... to eat

 

[mopwrd340]

Your car never came with cats i dont think its gonna help your problem hook your pvc system back up . your car dosent even have the raised spots in the floor boards for them which would make them hang down you really cant put them that close to the floor board in case of a lean condition which would turn them cherry red .

 

[Cranky]

I was thinking of putting cats on both my cars. I spoke to a muscle car garage about the exhaust smell and he highly recommended putting hi flow cats to cut the smell. He said their are various types that will cut the smell at various levels. Obviously the more expensive, the more it reduces the smell. He showed me a couple different designs and both looked like ceramic, but could be mistaken. He said todays gas is formulated much differently than earlier days and the smell proves it. After checking all the above mentioned suggestions, this could help. Btw, after putting EFI on m 71 Cuda the gas smell went down 70%.

Have a straight pipe on my 95 Dakota V6 and it reminds me of the way the cars smelled in the 60's....although not exactly the same but similar. Now I've been around non cat cars that really smell horrible and with my allergies being the way they are, I'm kinda picky on the way the exhaust smells. Now my /6 Belvedere had a more rich smell but it wasn't horrible but that's probably the difference between FI and carbed.

 

[Longroof]

If you guys are worried about the smell maybe you should sell your mopar buy a Prius and get some air freshener trees..... I just can't understand this.... but to each his own....

 

[A383Wing]

cats will maybe stop the foul smell for a little while, but if engine is not tuned correctly, it will destroy the cats within a month or so and you will be back to square one....

I would first get your PCV system put back on correctly, then find a shop that has an exhaust analyzer and have them sniff your tail pipes to see how rich or lean it is...then adjust accordingly

 

[Photon440]

Your car never came with cats i dont think its gonna help your problem hook your pvc system back up . your car dosent even have the raised spots in the floor boards for them which would make them hang down you really cant put them that close to the floor board in case of a lean condition which would turn them cherry red .

Running rich is what causes them to glow. They're busy burning all the fuel that your engine missed.