Is it normal for cat-delete cars to stink?

[maillemaker]

I recently bought a 95 GT convertible.

Someone has replaced the entire exhaust system headers-to-tailpipe. Catalytic converters are gone. As I posted in another post, it's pretty janky and hangs too low. I'm going to have it re-done by a shop.

I notice when driving that I can smell exhaust strongly in the cabin. It's entirely possible there is an exhaust leak somewhere.

Just want to be sure this isn't an artifact of having no cats.

If it is, I'm going to have to have cats put back on because it gives me a headache driving the thing right now.

 

[apsmith49921]

If it's catless it will smell

 

[RAU03MACH]

Not bad I still say if tuned right not real bad

 

[ttocs]

if it is catless you might have a hard time finding a place to do anything on it unless you want the cats put back on. The EPA has been cracking down on the small guys.

 

[RAU03MACH]

Love NM

 

[white95]

Yup, stanky exhaust is stanky.

 

[Frank.JD.Perez]

Yes

 

[ttocs]

stanks so good! I had a Cat go out on me a few years ago and decided to try catless since it was cheaper. With the side exhaust it could get heavy enough at lights that I would roll my windows up. I was happy to find someone selling a pair of new cats on marketplace for $125 that I installed.

 

[Notthenow]

Cats today flow well. Hell factory cars are making over 600hp running cats. And yes, no cats will still have some unburned fuel at times that will smell.

 

[maillemaker]

OK, so if I want to add cats back and keep the tubular headers, what are my choices? Are there "performance" cats?

 

[Notthenow]

Yes, there are. Check Mustang parts houses, as well as Summit. You might have to figure out the correct flange, band connectors and pipe size/reducer. The all metal race versions flow best, but don't clean as well as the ceramic.

 

[Notthenow]

Mounts cat as close to the collector as will fit so the gases are as hot as possible. They need to be hot to work.

 

[Slice]

I bought a 1996 Mustang GT. It has H pipe and no cats straight out to Flowmasters at the rear. I don't smell anything. Prior owner did it and he was an enthusiast. Maybe he tuned it just right? I don't know but I'm pretty happy with the setup.

 

[Notthenow]

Headers?

 

[Rod]

I have an off road H pipe with 2.5' Flowmaster "cat" back and full tail pipes. It smells a bit more than it did with cats but if tune is on point it will not be harsh. I recommend checking the O2, MASS, MAP, Temp sensors. If it's running rich it will smell so bad it will run of the car.

 

[Slice]

Headers?

No headers just cat delete with H pipe and Flowmasters but no stink.

 

[Notthenow]

With stock manifolds the O2's are better able to control the mix being closer to the head. I assume stock cams, etc?

 

[Slice]

With stock manifolds the O2's are better able to control the mix being closer to the head. I assume stock cams, etc?

As far as I know stock cam set up. Only mods under the hood are a BBS intake system and an under pulley.

 

[Notthenow]

The stock set up tends to run lean, so there is room before excess fuel is left.

No smell even initially when cold?

 

[Slice]

Correct no smell at all. I guess I should consider myself lucky. All mods were done by the previous owner so I'm not really sure why it's good. No warning lights on the dash either but I can see that somebody had the cluster out once because there's a screw missing. I think back then they had bulbs you could remove as opposed to new cars which have hard soldered in LEDs.