Does cat cut down on exhaust fumes?

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SuperT

SuperT

10 Year 15 Year
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Sep 15, 2007
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14
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188
Location
Littleton, CO
Had to drive with the back glass down today to haul a small bit of lumber and was almost overcome by exhaust fumes driving back home. I always smell it when I have the side windows down too, but today it was really bad. I have a completely new exhaust on this truck with no leaks.

Does anyone know if throwing on a catalytic converter will cut down on the fumes? Is there any other remedy, or do I just have to accept that all pigs are going to be stinky?
 
Pic of where your exhaust exits please.
 
Tailpipe.
DSC00525.webp
 
I'll probably get flamed by the experts if I'm wrong:rolleyes: but for what it's worth. I always thought that if your exhaust exit is too close to coming out the rear as opposed to exiting straight out the side the draft in the open rear window will suck the fumes in. But you said with just the side windows open you're still getting fumes. So you must have a leak somewhere or a leaky rear window that is always sucking in fumes?
 
I think pigs are basically built to suck exhaust back in. Aside from running stacks up the top like an 18 wheeler, I can't see how it could be reduced
 
fumes

I thought mine was the only rig that was "gassy". I don't like it! My exhaust exits infront of the rear drivers side tire and it still pulls in. I did lessen it though when I went through the floor and sealed a ton of little holes. I think also that when I get the door rubber all replaced it should do better...? We'll see.
 
I can see where moving the tailpipe location might reduce the amount of fumes coming in through the back window. That might help, but what I really want to know is if I installed a catalytic converter, would this reduce the amount of fumes or smell of the exhaust? I don't like the fumes coming in the windows of the truck or stinking up the whole intersection or my neighborhood while idling.

Has anyone had both a cat and non-cat set up? Could you tell the difference in the amounts of fumes or odor?

I can't imagine these trucks smelling this much when they were new, even the pre-cat years like mine. Maybe it's just cause its an old truck, old engine. Can anyone say that they have a 55 that doesn't smell?
 
A cat will cut down on fumes in a huge way. It's what it does. I'm always a bit amazed when I fire up the pig in the shop. It makes me remember the bad old days when I reeked of gas fumes every day. We run cars in the shop all the time these days without ever hooking up the exhaust tubes. A big part of that is FI, but cats help a lot.
 
Lil'John said:
My 55 smells fine... OTOH, I've got a 5 year old engine with 30k miles on it (ie 6.0L Chevy Vortec ;p) I don't run a cat... my exhaust exits roughly the same spot:


If your engine is running so poorly you are getting a serious case of fumes in the car, the money you will spend on a cat would be better spent fixing the underlying issue:confused:
Click to expand...

That would be a great solution, :idea: but I don't even really want to spend the money on a cat, let alone a vortec swap. (Not yet anyway.)

Actually, I've got the 2F running like a champ... just stinks. I could probably adjust the fuel mixture a little, which I will probably do, but I don't think it would change much.
 
Gumby said:
A cat will cut down on fumes in a huge way. It's what it does. I'm always a bit amazed when I fire up the pig in the shop. It makes me remember the bad old days when I reeked of gas fumes every day. We run cars in the shop all the time these days without ever hooking up the exhaust tubes. A big part of that is FI, but cats help a lot.
Click to expand...

:D Thank You. I might just try a cat then. I know I might get blasted by some anti-emissions people, but if makes things better and makes everyone around me happier, all the better.
I've been thinking about converting the 2F to fuel injection too. So that makes it sound like an even better idea now.
 
Lil'John said:
Just because it runs well doesn't mean it isn't running overly rich.

My old 40 ran great but a bit rich. The exhaust was a little on the strong side (no cat)

One thing you could do is take it to a smog shop and have them run a "pre-test" on it for $10-$20. That will absolutely confirm where you are having issues.
Click to expand...

Yep, couple more good ideas for the short term and on the cheap. Thanks.
I'll probably tinker with it for a day first to see if the will help. I've had a couple 40's both with 2F's that stank a little too, but I don't remember them being as bad as the pig. Then again, I don't think I cared as much back then either.
 
I would do FI first and then cat.

You put a cat on a carb'ed engine that is running too rich and that cat will get hot as hell.

I think some states specifically state that you cannot add cat to a vehicle that was not spec'd for cat b/c the heat the cat puts out could be dangerous to the vehicle/occupants.

Be careful, keep us posted!
 
A cat it a little furnace that burns un-combusted gasses. Carb'ed engines have a LOT more unburned hydrocarbons than FI, so the cat will work harder and get hotter. They did put cats on carbed engines though.

FI first would be better, but a lot more expensive and a lot harder.
 
I will probably try to do the FI set up myself. I would have to have a muffler shop put on the cat (I don't know how to weld). They could also tell me if this is legal, safe, and a good or bad idea.

I won't be doing this anytime soon, since my time and money (mostly money) are going towards my Trekker right now. Eventually I'll put more time (and money) into the pig though. I'll just have to add FI and cat to the to-do/wish list for now.
 
no fumes in mine unless the rear is down, dual tips exiting to the side under the rear quarters. my moneys on leak.
 
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