Skip to main content

Should You Consider a Catalytic Converter Delete?

Catalytic converter deletes are sometimes recommended as a solution to more than one problem with a car. Is this really ok despite what some popular mechanics and many forum commenters have to say about it? Plus see how a cat delete is done and what it did for a Miata.

The Catalytic Converter Problem
In the past we’ve learned about the most common problem of having a catalytic converter on your car is when the catalytic converter is no longer on your car. In other words, the common problem of catalytic converter theft that can leave you with a noisy vehicle that spews noxious exhaust and having to follow laws that dictate you must have a catalytic converter replaced even if it is stolen.

Related article: Why Not All Ford Catalytic Converter Thefts are Bad News for Owners

If that is not bad enough, there are also the additional repairs that often have to be done because the thief was no rocket surgeon and did some serious damage to your vehicle while cutting out the converter.

Catalytic Converter Delete
One proposed solution to this problem has been to ignore the loss of your catalytic converter and just weld in a piece of pipe in its place. But is this good or even sensible advice? According to a recent Scotty Kilmer YouTube video, it might not sound like such a bad idea despite his repeated statement of the fact that it is illegal to do so throughout most of the US.

Here’s Scotty’s take on what it means to go without replacing a stolen or damaged catalytic converter.

Please Note: Scotty’s answer regarding catalytic converters is only from timepoint 0:00 to 1:30 in this 10-minute video.

This is Illegal as Hell But Makes Your Car Run Better

Scotty Missed on This One

While Scotty is correct that there are vehicles that may run fine and even better without a catalytic converter…this is not an absolute for many vehicles.

The positive points often made with having a catalytic converter delete is that your vehicle may demonstrate increased horsepower, increased engine life due to less stress (such as temperature), better throttle response feel to your ride, a louder more racy/throaty exhaust sound, and more miles per gallon on gasoline due to that removing the catalytic converter automatically reduces engine backpressure. Kind of like wearing a facemask during Covid---taking air in and exhaling out is significantly restricted.

The biggest plus, however, is that it appears not to cause any catastrophic damage to an engine.

The cons of doing this Scotty points out is that it is illegal to do a catalytic converter delete with the exception of one or two states---but this is based on if there is no emissions testing required and therefore you will not likely get caught doing it. In truth it is illegal throughout the US and the emissions testing in said state(s) is a county-by-county policy.

Other cons to a catalytic converter delete include:

• Harm to the environment and the air we breathe
• An annoying drone-like sound within certain RPM ranges depending on the vehicle
• Potential noxious odors from your exhaust while idling that may go away later
• Check Engine light code warnings requiring a bypass of sorts to trick the engine sensors

But the biggest potential fail to really consider is whether or not your vehicle’s gas mileage really will improve. While with less stress on the engine, it would seem a given. However---in real-world practice depending on the model---you can also reasonably expect that fuel efficiency might actually perform worse because the engine is already designed to be as fuel efficient as possible WITH a catalytic converter installed.

In other words, removing the catalytic converter will likely require some specialized tuning to get the remainder of the fuel system to operate optimally whether it be a part, software change, or jerry-rigging that could lead to new problems with your car.

Related article: Car Tune-Up Truths Car Owners Need to Understand Today

That said, receiving the oft-repeated benefits of a catalytic converter delete is not guaranteed, nor should having a cat delete really be encouraged.

Here's a Cat Delete with a Miata

But if you decide to experiment with your car and its performance with a catalytic converter delete, here is an interesting video that showed how it was done with a Miata and just how much of a performance improvement was achieved so that you can decide for yourself if this is a route you would want to take with your car.

Is a Cat Delete Worth It?

Related article: Catalytic Converter Criminal You Would Not Expect

And finally…

For an additional related article here is on about “Catalytic Converter Theft and The Vehicles That Are Targeted Most Often.”

COMING UP NEXT: Catalytic Converter Anti-Theft Products Reviewed

Timothy Boyer is a Torque News automotive reporter based in Cincinnati. Experienced with early car restorations, he regularly restores older vehicles with engine modifications for improved performance. Follow Tim on Twitter at @TimBoyerWrites for daily new and used vehicle news.

Image Source: Unsplash