Anyone gutted their catalytic converter?

Anyone gutted their catalytic converter? I'm curious about the effort involved, plus how the car ran and sounded afterwards.

In the state where I live the car no longer requires inspection. I also find it difficult to imagine a 42-year old catalytic converter is still doing anything useful.

Other options I've considered are test pipes (why do they cost so much?). Or the elusive European ANSA version of the exhaust system.

 

Actually a cat wears out from mileage, not time. It should last 100k+ miles. You can probably sell your good cat for enough money to buy two test pipes, so I'd suggest that instead of destroying your perfectly good one.

Case in point: my '86 911's original cat was still working great at 140k miles.

 

Agreed. The cat would have value to people in places such as California, where OEM components are mandated.

 

Some folks find the fumes too much after cat delete (me included). Suggest you keep your cat in case you want to go back to stock. An exhaust shop should be able to fabricate and fit a test pipe for you - Cheap.

 

Why would anybody do that ? Buy a test pipe instead , and while your at it, why not a Tubi .

Thank you

 

I have gutted a pair of of really bad cat from a two cat 308 and use them as test pipe, it works really well.

 

To help pass a visual-only inspection in some places/countries. Unannounced roadside police inspection etc.

 

+100 I can also attest to that

 

Why not using a modern sports cat?

@Fabspeed Motorsport sells one. I purchased mine there on august, I hope one day they will ship it.

 

What do you think of these ?
https://www.ebay.ca/itm/313630448937?hash=item4905d4dd29:g:HckAAOSw4ZhhDnQH

 

"Why not using a modern sports cat?"

Certainly that's an option but the Cats and "test pipes" from the typical aftermarket "sports" suppliers are insanely priced. As noted, any exhaust shop can provide cats/test pipes for a fraction of the "sport" price.

 

I have not gutted but I replaced oem original fit and the stink factor much improved with new cats. No significant bhp increase without cats, so replacing with new may help with stink factor. I submitted a write up on an aftermarket set up that worked well for my GT4.

 

I made two test pipes, I think it was less than $50 for the flanges, pipe and gaskets. I put the cats and air pump in storage in case anyone ever wants to put them back on.

 

Not in 21 years , I smog the car every 2 years by swapping out the test pipe for the cat ,

Thank you,

 

Sure, lots of people do that.

There may be no such thing as a random stop or a checkpoint where you happen to live. The world is a big place. There are places where it happens. There are places where the police check tire tread depth of vehicles parked in public. There are places where dashcams are illegal etc. etc.

 

That appears very "fishy." People steal catastrophic converters because they are valuable due to the precious metal content. Advertised ebay price does not seem realistic.

 

Cats can last a long long time. I've got cats on my mid 80s Benzes that are over 30 years and 200k miles old and they still work. Not sure what quality cats Ferrari used but I think its a safe bet the exhaust will stink when the cats are gone.

 

Funny - one of the primary objections when cats were introduced in the 70's was the rotten egg smell produced by them. You could always tell, sitting at a stoplight, if the car in front of you had a Cat! Back then, cats produced a stinky smell; properly tuned cat-less engines did not. Go figure...

 

Here's a listing at Summit - prices might be lower than you'd expect: https://www.summitracing.com/search/part-type/catalytic-converters

Of course, you'd need to make sure the car has the proper A/F and exhaust gasses at acceptable levels... if you're already running rich, you'd just poison it.

 

They sure are and Summit is known legit. Didn't think you could get something like for what seems like a reasonable price.

 

It's inexpensive because it doesn't have some boutique 'performance shop' label on it! OTOH, If you need a chrome Cat so all the folks who regularly crawl under the car can see it/be impressed, you'll have to pony up the $1000 for a boutique cat!

 

They're also cheap because they're universal fit, which means they don't come with flanges or the labor to weld them up. I'll bet they also don't contain much catalyst in them so would need to be replaced every 15-20k miles.

 

You are right but the welding/flanges would probably not exceed 100 bucks at an exhaust shop.

Here is an interesting link re Cats. The second page mentions the required EPA warranty.: https://static.summitracing.com/global/images/instructions/flo-converter_tech_sheet_5_3_12.pdf

 

Mike, I remember those days. It seems that whenever I come up on a car without a cat, I can smell it a good 1000 ft before catching up to the offending car. But I certainly have no experience with cat-less QVs or the earlier injected 308s. Would they run lean without a cat?

 

The OEM tuning would be lean at the idle/low speed range for use with the cat/low emissions. If you remove the cat, in theory the mixture doesn't change and there would be no difference in how the engine runs. but the O2 sensor - if still enabled - would signal the system to adjust the mixture appropriately. I'm GUESSING that it would see the Catless output as slightly rich and try to lean the mixture even more but I really don't know.