Catalytic Conversions

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It’s difficult to spend less on gas when you haven’t got any control over the price of gas – or the diminishing value of the money it takes to buy it. But there are ways to reduce what you spend – which is a way to have more money available for gas (and other things, besides). 

One such way is to not replace your vehicle’s catalytic converter when it fails, falls off – or is cut off, as by a thief with a Sawzall.

The reasons why you might decide to do this are three.

First, why play by the rules when the rule-givers don’t? It is both stupid as well as servile to obey the various edicts, to bear the various costs, when those who impose them ignore them and are clearly both hypocrites as well bent upon our enserfment via the edicts and costs they impose on us.

As for example them declaring themselves “essential” during the “lockdowns” ordered by themselves.

They don’t have to worry about the cost of gas – which they have caused to increase, by purposely reducing supply while at the same time increasing effective cost by decreasing the purchasing power of money (by creating more of it, our of thin air, and disbursing it to various court favorites) because they don’t have to pay for it.

We do.

At least twice.

Joe Biden hasn’t paid a cent for gas in 50 years. We have paid for it all – via being forced to pay him to enserf us, via the theft styled “taxes” we’re forced to pay that finance our enserfers. Joe – and the other rule-givers – enjoy free transportation at our expense. Which they then make even more expensive, by depreciating the purchasing power of whatever money we have left, after “taxes.”

It seems reasonable as well as right to even the balance sheet a bit – on our favor.

Catalytic converters are expensive – especially when you are expected to replace it after some blue-haired skunk who voted for Biden stole it and probably will, again. I have previously related the story of my sister, who lives in the Golden Country of Southern California, where nothing is done to deter “homeless” people from going number two on the sidewalk or to prevent/punish people who shimmy under cars with Sawzalls to steal them. The enforcers of the rule-givers will not come – much less arrest – such thieves. So why should anyone feel obliged to replace what they steal – and will steal, again?

It would be as stupid – as degrading – as going back to the place where you got mugged and offering up your open wallet, again. Which we’re all about to do again this April15th, eh?

A typical “cat” costs about $150 for an aftermarket replacement; a factory-spec one can cost twice this much. Many late-model vehicles have several cats. It amounts to a lot of money.

Even if it’s “only” $150 to replace one of them that sum can still buy you about 38 gallons of gasoline at the current $4 or so price per gallon, which is enough to fill up the typical car’s 15 gallon tank more than twice.

A nice rebate. “Stimulus,” if you will.

There is also the savings you’ll wrest back by running sans the cat. By using less gas. Eliminating the cat can increase the mileage you get by 2-3 or even more, depending upon how old and fouled and thus restrictive your cat was.

In order for the cat to do its thing – chemically scrubbing the exhaust – the exhaust must pass through very narrow passages that form a lattice, like a honeycomb, inside the converter. If you have ever cut one open, you will already know all about it. Over time, carbon accumulates on the surfaces of the lattice, gradually increasing exhaust backpressure, which reduces the efficiency of the engine.

A new cat would restore the proper rate of flow – but then, you’d have to spend money to get one. A straight pipe costs $10. And you might end up with a vehicle that uses noticeably less gas than it did before – or even when it was new.

Now, you may be concerned about the “check engine” light coming on – if you take the cat off. And it will – unless you take steps to fool the computer into believing it’s still on. More precisely, fooling the oxygen sensor into believing the cat is still in place. This, in turn, will keep the “check engine” light – which isn’t about the engine, incidentally – from coming on. It is designed to come on in order to nag the owner to have the emissions control system checked – and to alert a government-mandated emissions inspector to that you may have “tampered with” or “defeated” some emissions-related part.

There are at least two ways to keep the light off. One – which I will detail in a subsequent post – involves screwing a modified spark plug non-fouler (available at any auto parts store or online, as via eBay Motors) into the fitting in the exhaust pipe that the 02 sensor screws into . . . and then screwing the 02 sensor into it. This puts the 02 sensor out of the exhaust stream sufficiently that it doesn’t sniff as well.

This will get you past the cursory inspection – the inspector checking to see whether the  dashboard light’s on, which would cause you to fail inspection. To assure you don’t fail the visual inspection, you can wrap the shell of a cat around the pipe – making it look as if you still have a cat.

Some will find the above obnoxious – but far less so than the government that has purposely and (arguably) with malice made life so miserable and expensive for all of us.

Sometimes, it’s necessary to do what one must in order to make up for what the government is doing to us.

Plus, doing it will make you feel really good, too.

. . .

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  1. Great article!

    I’ve always wanted to remove the driver and passenger air bags in my early-2000s vehicles. Eric, I hope you can illuminate us on how to disarm these front-seat bombs (legally or not).

  2. Nice!

    However, I don’t even know if my Renault Duster has a cat, nor do I care. It just crossed 30,000 km (18,000 miles) after 3-1/2 years of driving in Uruguay, so even with gas at USD 6.30/gallon, I’m not overly concerned about mileage.

    As with “health” insurance, which Byzantine complexification I’ve recently had to deal with for my son in Arizona, saaaaaaaafe “emissions” are another reason to be glad I do not live in the Untied Snakes (February marked 15 years).

  3. Hi Jim H, hadn’t heard about using E15 gas this summer….this makes sense(sarc), now we eat less and corn goes to making gas instead of good whiskey. What are us drunks supposed to do, drink wine? Yuck.””

  4. How about replacing the cat with a straight bit of pipe and only putting it back on for inspections. That way you get better gas mileage, the thing won’t wear out sitting in the garage and no twat can nick it.

  5. Do you figure a shop will install a straight pipe on my 08 Subie with bad cats? I also have a nice ‘sporty’ hole near my muffler. Is this easy enough for someone who doesn’t have more than a hydraulic jack and jack stands? With very rusty exhaust?

    I’ve been scamming Ohio for the last year or so with my old Indiana plate. I claimed to have still lived there this year as Indiana’s plate renewal was cheaper. I’m always looking for ways to screw over the State.

    I need to renew my license plate soon and my check engine light comes on and off quite a bit.

    • Hi Andrew,

      A shop may do it, if you know the owner – or rather, if he knows you. Enough to trust that you will never reveal that he “tampered with” an emissions control device. Serious Hut! Hut! Hut! repercussions for him if the thugs ever find out.

      Exhaust work isn’t technically difficult – just sometimes difficult. Usually due to rust. If it’s not too bad, you can usually soak the nuts you need to remove with PB Blaster or similar and get ’em loose; cut and wrangle off the rest. I’m doing my whole exhaust. I already have the head pipe. I’m waiting for some other bits and pieces…

      • If she’s a forever rig a proper stainless exhaust can’t be beat, even if you have to pay a custom exhaust shop. I’ve found the “stainless” options from the aftermarket parts stores only last a few seasons in the rust belt. Garbage!

  6. Where I live in So.Oregon the emission regulations are based on how old the car is. If the vehicle is in a certain metro area,

    Inspection Exemptions

    Within the testing areas mentioned above, the following vehicles are exempt from Oregon emissions testing:

    Motorcycles and low-speed vehicles, including:
    All-terrain vehicles (ATVs).
    Golf carts.
    Diesel-powered vehicles weighing 8,501 lbs. or more.
    Vehicles older than:
    Model year 1975 (Portland-Metro area).
    20 years old (Medford-Ashland area).

    My 1993 Geo Metro is exempt – so ring that up as another reason to drive a used car. I used to scrap vehicles all day everyday and the selling price of the used cat is far below a new one, I think the most I ever got was $30 but that was years ago. Thieves know which ones are worth the most – which is why the Prius is targeted.

    So rules of thumb while living in USSA:

    1. Don’t live where the government micromanages you. Rural areas have less restrictions.

    2. Don’t own a targeted vehicle.

    Also – you can take the guts out of a cat, and leave the body in place – and you can do that easily when refurbishing the rear part of the exhaust – make the cut behind the cat and use a steel rod (tire iron) to knock the contents loose. Rarely does the pipe rust out before the cat because of the high heat – it rusts where water pools downstream.

  7. It seems the gatekeepers have wiped the jungle site and evilbay of dedicated O2 spacers. Some of these had 90* or 45* bends to fit in tight spots. Some even had replaceable orifices of different sizes retained by a snap ring to adjust how much the sensor can sniff. Now they can’t be found so the dorman 18mm non-foulers are the only option if space permits. As another commenter noted, one non-fouler needs to be drilled out 1/2 inch usually. Try just one at first, if you still get cat insufficient code stack the second non-drilled non-fouler over the first to further restrict the sniffer.
    Another alternative for emission states that plug into the obd2 port or look for a check engine light is to pull the post cat O2 sensor and goop some jbweld over the holes. It’ll screw back in and look normal for visual inspection and turn your light out for 500 or so miles until it burns off. This worked for me in the vortex of evil (new england) for years after my car went into limp mode and cooked the cat.
    I’ve heard of O2 simulators and other electrical hacks but never gave them a go since the mechanical means listed above work brilliantly. It must really chap someones ass to have their well engineered tattletale tech thwarted by ten bucks of materials.
    Now if we could only lean fuel injection to our liking like a carb we could get even better mileage from these new pigs.

  8. Might as well remove the converter and sell it so no one else can. You’ll see to it that the cuts are even.

    A CAT thief was cornered in an out building on a farm one night in March of 2021. The sheriff arrested the culprit and was given a three year prison sentence with all but 120 days suspended.

    A year later, probably returned to his avocation as a CAT thief, he was murdered by an angry acquaintance.

    Had the thief been sentenced to three years in the hoosegow, he wouldn’t have had the chance to return to a life of crime and subsequently murdered.

    Crime pays until it doesn’t.

  9. Biden’s plan to Whip Inflation Now, as ol’ Gerry Ford used to say:

    ‘The president is set to announce Tuesday during a visit to an ethanol plant in a remote town in Iowa that the EPA will eliminate restrictions on high-ethanol-content gasoline to be sold during the summer months.

    ‘The decision will allow gasoline with 15% ethanol to be sold between June 1 and Sept. 15. Normally only a 10% ethanol blend can be sold during that time period to reduce smog caused by the 15% blend’s higher volatility.

    ‘Administration officials say the decision could shave as much as 10 cents off the price of a gallon of gasoline.

    ‘Iowa’s two RINO senators, Chuck Grassley and Joni Ernst, immediately celebrated the news on Twatter.’

    Dementia Joe’s gonna smog up our skies by burning corn for fuel, in a feckless attempt to head off a Demonrat Donnybrook in November?

    Twat …

    • As long as it’s labeled so I can avoid that stuff.

      My car is not especially old, but E15 is specifically not recommended in the owners manual.

    • Hi Jim,
      This deathanol policy pushed by the big-Ag lobby and the politicians they own is wrong on so many levels. First and worst is diverting a food staple that is becoming ever more unaffordable from the serfs that need it to actually eat. Then there’s “the science” for real that shows your mileage will be lower since there’s less energy in a gallon of ethanol than a gallon of gas, so you can save 10 cents a gallon but will use more so at best it’s a wash. Last but not least is how ethanol will eff up your fuel system, I have to pay about ten dollars a gallon for straight gas for my snowblower since the ethanol laced “gas” wrecked the older one I had.

  10. ‘they have … [decreased] the purchasing power of money (by creating more of it, our of thin air)’ — eric

    And how … this morning’s Consumer Price Index report came in at 8.5%, worst since the early 1980s.

    About a quarter by weight of the CPI is ‘owner equivalent rent’ (OER) — a fictitious number that’s based on a poll (‘What do you think your house would rent for?’), not actual prices.

    Within this ugly CPI report, OER was rising at an annual rate of … yes, only five (5.0) percent, comrades!

    Whereas in my area, both house prices and rents rose around 30 percent in the past year.

    That is, correcting for the US fedgov’s phony statistics, inflation (currency debasement) actually is blazing at around 14 percent — banana republic territory.

    ‘They’ thought they could ‘just print’ three trillion dollars in the past couple of years, and nothing bad would happen.


    Now the fedgov’s feckless fraudsters and counterfeiters are turds on the run.

    WANTED FOR CITIZENS ARREST: Jerome Powell, enemy of the people.

    • Jesus the Christ drove out the bankers with a whip not once, not twice but three times out of the Temple they had converted to basically a central bank so I don’t think you will get chastised in the hereafter for doing the same. Bankers are as He called them “a den of thieves” which was the reason pharisees had him murdered.
      Today they’ll do the same to anyone trying to eliminate them. Most of today’s fluoridated land whale citizens don’t have a clue thinking central banks are as necessary as the kill shots they took.

  11. One of my Norton Motorcycle Club members told me he has had (3) cats stolen from his car in Portland.
    How about taking some chain-link fence and lay it flat to park over. then hook up 120vac thru a switch and extension cord. Security cam to notify when the culprit is working and zap. Rubber tires should protect the car from any damage.
    Just dreaming out loud.

  12. Off topic, but interesting: Horrible app developers face abuse from UK drivers.

    FTFA: “One online review for the app said: “In East Germany, citizens were encouraged to report their neighbours to the Stasi for even the smallest societal infraction. ‘Congratulations’ on creating a modern day version of that. If you couldn’t tell, I’m being sarcastic. This app disgusts me.”

    • “The more artificial taboos and restrictions there are in the world, the more the people are impoverished. … The more that laws and regulations are given prominence, the more thieves and robbers there will be.” Lao Tzu

  13. After my ’02 A6 Avant fouled the factory CATs, Audi wanted $7,000 to replace them! The after market pair that I bought cost about $300 each. The local shop almost didn’t want to put them on. But it didn’t take long and the CEL came back on with O2 sensor codes.

    I got the transmission range sensor fixed the other day and that shop inspected the exhaust. Now they’re telling me that the muffler assembly is rusting out. I gotta get that fixed somehow before it falls out when I’m driving.

    Luckily. where I live, there isn’t any smog inspection or that car would be in the junk yard.

    • Hi EM,

      $7k for replacement cats. That’s what I call planned obsolescence!

      Incidentally: Back in the ’90s, my ’76 TA was able to pass “smog” – the tailpipe sniffer test – despite not having cats. It looked as though it had them. But they were just dummies. But a few turns of the idle mixture screws and some timing adjustment got me through!

      • Still cheaper than a new car. By A LOT.

        And in my area of the state they do inspect for emissions, much to the state’s chagrin (EPA requires it due to a large city in the next state over)

  14. Glad to live in a county that doesn’t require an inspection. Seems I remember some years back the EPA was trying to expand emissions mandates to cover the whole country. They failed. It seems the data was manipulated (surprise).

    Setting up testing equipment, in sparsely populated areas out in the desert, apparently measures dust and other airborne particulates as emissions. Probably wont be long before they reconstitute the scam for the safety of the children, (the same ones they’re trying to poison). After all, who doesn’t want to breathe clean air? Oh thats right, a large segment of the population who long not to breathe free.

  15. There are a couple of other ways to take care of the nag light. If your car would allow it (i.e. your instrument panel isn’t too overly complicated), you could put a piece of tape over the indicator so it doesn’t bug you. Or you could learn to ignore it.

    Of course, what you’re proposing would probably only work in states where there are no emission inspections, and would be easier in states with no regular vehicle inspections in the first place. I’m fortunate to live in such a state.

    How about this – if they really want to put a stop to this, why not enforce it at the point where the thieves sell their stolen property? I mean, didn’t there used to be laws against trafficking in stolen property? Junkyards that make you verify that the cat you brought in was actually yours or legitimately obtained (i.e. a mechanic) by verifying VIN numbers or whatever likely see very few, if any, stolen cats. Just a thought.

    • Indeed, Jim –

      But since there is no significant (if any) disincentive for people to steal other people’s cats – as in the case of my sister out in San Diego – it’s pointless to “play by their rules” and go out and buy a replacement that’s very likely to get stolen, again.

  16. Love this article, the non foulers work well. They come in packs of 2, the 18mm ones with crush washer are the best. For the average Joe the most difficult part is the drilling out of said adapter, as they are slightly hardened, bore them to a 1/2″ for most sensors, 17/32″ for larger ones,no larger though or the adapter becomes too thin.

  17. Bravo, Eric.

    But, $150 is the opening ante. I doubt the thieves are cutting the cat at the connection points leaving clean mounts to replace it. No, they’re hacking away at the pipes pre and post cat. Thus, you have to replace those as well. And, of course, everyone has a Miller-Matic ready to go to weld up the replacement pipes if needed. And has the tools to make it a DIY project. Everyone has a lift in their garage…right? Hey, a set of 3 ton jackstands will only set you back about 60 bucks. And who doesn’t love crawling under their car to work on it?

    I would estimate parts and labor would probably end up north of $600 when all is said and done…and taxed.

  18. Eric, seems like this is much cheaper in the US than the UK. Cat converters here are 1-2k GBP, infact the main reason cars from the 2000s are scrapped these days are the cat converter either failing or being nicked. Which is crazy that the whole care ends up in the junkyard for the sake of a minor amount of some gas in the air….

    Maybe its because we have European cars here, but the job to remove the damn thing is also quite expensive normally – (as I was told they need to re-program the computer to ignore the fact that there is no pressure difference between the before and after sensor). Or maybe we’re over complicating it….

    Another big issue we have is with the diesel particulate filters (as we have lots of diesel cars). They also tend to fail after about 7-10 years (unless you know how to manage it). Again a 2k or so replacement (or a 500 quid removal, installation of empty one, and remap of ECU to ignore it).


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