Hollowing out the catalytic converter on VX

[GasSavers_JoeBob]

Originally Posted by JoeBob

I tried removing the cat on my Chevette some years ago when I was trying to track down some problems with FE. Over several tanks, noticed no difference in performance or FE. Put it back on. Conclusion: A properly functioning cat has no deleterious effects on performance or FE. Better to use it, be in legal compliance, and pollute less.

The car did sound pretty cool running straight-piped, however. But the stern stares from several Sheriff's deputies convinced me that it was in my best interest to return the exhaust system to its original condition...

[VetteOwner]

Originally Posted by JoeBob

The car did sound pretty cool running straight-piped, however. But the stern stares from several Sheriff's deputies convinced me that it was in my best interest to return the exhaust system to its original condition...

lol my chevettes has rusted off in several occasions and i must say straight piped does make it sound neat makes it sound like a rally car

mine currently has no cat and stock muffler. at idle it has a nice little diesel sound (its a gas engine) it can and does pop when engine braking sometimes or if i rev it.

heck if motorcyclist can get by on that stupid excuse by saying straight pipes make me more noticeable (dont need to notice you in my house a mile away from the highway) so i don't get hit I can use that same excuse with my tiny car that goes nowhere fast.

cops around me tend to like my car, one just laughed as i went buzzing by goin 85 in a 55

[dieselbenz]

Originally Posted by willix

most all cars pass emmissions tests without a cat since the late eighties.

This is NOT true.

[willix]

Yes they will, pass emissions yes, visual/physical inspection fails no cat. Fuel injection & obd 1 cars are very well managed by engine/emission controls. 1986-87 the new age of V6's & 4's multi over head cams as well as the push rod motors, body & port injection better best thing since sliced bread. American & japan

[trollbait]

Is it pass emissions as in pass the minimum standard, or pass in the car's certified rating? Will the SULEV car still be SULEV without the cat, or does it drop to Bin II?

[theholycow]

I would define "pass emissions" as meaning that you are allowed to continue driving the vehicle without changing or repairing it.

[fowljesse]

Just to answer the question; I found no ill affects when I gutted mine. It was so clogged that I couldn't see through it, and a new one for my car is around $250. It sounds better now (barely noticeably louder from the outside), and my mileage went up (of course, since it was clogged), and I have passed yearly emissions 3 years since then. I get about 5 more MPG than EPA says, when I drive normally, and a couple more when driving for FE. The MX-3 V6 burns clean, though. I don't know about other cars.

Originally Posted by giperbolic

I did search and this was asked once before, but I couldn't find an answer. What are the negative affects of gutting the internals of catalytic converter on VX except noise, smell, high NOX emissions? Are there any FE, O2 life, engine affects?
Also, how do check if cat is bad? The engine I swapped in my car has been sitting for 11 years, so I figured cat is rusted and clogged, but I haven't opened it up to look. Engine is running.
Thank you.

[trollbait]

Originally Posted by theholycow

I would define "pass emissions" as meaning that you are allowed to continue driving the vehicle without changing or repairing it.

Some states actually measure what's coming out of the tail pipe though. Then it's a matter of the law requiring that the car meets it's Carb or Fed rating, or some minimum rating. A blanket statement of "pass emissions" may not apply in all areas.

I knew a guy who had the cat hollowed out on a Ranger here, and had no problem passing inspection.

I don't know what platinum is going for, but selling the old cat to a recycling shop will offset the cost of a new one.

[theholycow]

"Pass emissions" is definitely dependent on jurisdiction. In RI, the car is put on a dyno and a sniffer is put in the tailpipe. Cars over 25 years old (my Buick) and trucks over 8,600 pounds (IIRC) are exempt.

[GasSavers_BEEF]

in NC it is done county by county. the county I live in only requires the OBDII check which means you fail with a CEL code. older than 1996 and they don't care.

the county beside of mine has no emissions. their inspections run $9.10 where as mine is right around the $30 mark. they also have the worst schools around and little to no industry.