928inAtlanta

If a car is running without a catalytic converter, will the exhaust smell more?

RyanPerrella

no you wont notice it. If you smell exhaust fumes you have a leak and i suggest you find it ASAP, the CO.2 can kill you

FlyingDog

I'm assuming you mean outside the car like can a cop tell if he's following you. Usually it is noticeable, but barely. Driving down the road other drivers should not notice if it's tuned correctly and running properly.

Mrmerlin

you will be able to tell the difference cat VS no cat, at idle and standing behind the car, and while its driving if your close enough , and there isnt much wind you may be able to tell if there is not a cat on board , as the car will smell like a pre 74 GM vehicle, or pre 86 light truck, so shut the engine off if you get pulled over and your not running a cat

Shark Attack

I find it VERY noticable by smell. its just stinky

Big Dave

I've been told by people traveling behind me that the exhaust without a catalytic converter does smell.

928inAtlanta

Thanks for your responses --- seems like the exhaust is "stinkier" without the cat.

JimBob951

Depends on your definition of stinky! Definately a different smell. I used to think the smell with cats was stinky! I remember back in the day when cats first came out, thought they smelled really bad, like farts! lol Now here in FL, so many people ditch their cats, and that smells bad as well, guess we all got used to the smell with the cats. Without them, there's more of a gas smell.

MGW-Fla

Definitely has more of a bit of a gas or exhaust smell without the cats, mainly upon startup or at idle when you are standing outside the car near the rear half. While driving I doubt most would smell it. If they were close behind you at a stop light with their windows down they would though.

SteveG

'85 was running rich or so the sniffer said. Couldn't find the cause til we went to replace the cats and found they had been gutted by PO. Maybe it just blew out, but ??? It smelled very sweet or stinky depending on your POV. I had replaced lots of hoses, etc, but the mechanic said he found a vacuum leak as well. It has been said here that if the car is running properly, it will pass w/o cats. I sort of thought he might have been justifying his bill, so I don't know but it smelled.

Imo000

My bother's ,'83 had a Y pipe and no cat. That thing would make my eyes water when I was behind him and he was at WOT! A year later we put a can on to pass the emission test and the smell went away.

tommytomaso

my 81 has cleaned out cat and the smells just a tad different then befor, but my Nephues 82 euro smells terrible (just like an old Chevy truck). Not sure if it has anything to do with the 02 sensor, but their is a big difference.