Best High Flow Catalytic Converters-2021 Reviews and Top Picks

Nowadays, people are looking for more environmentally-friendly options for getting around. If purchasing a rand-new hybrid or electric car is out of the question, the best thing you can do for both your car and the environment is to a high-flow catalytic converter.

High-flow catalytic converters can boost your vehicle’s performance without spiking the emissions output. After making contact with a chemical catalyst, exhaust fumes are converted into less harmful compounds like CO2 and water

In this guide, we’ll show you what the 5 best high-flow catalytic converters are and how to choose the most appropriate model for your vehicle.

Comparison Chart:

Image Product Features Price
AUTOSAVER88 ATCC0006 AUTOSAVER88 ATCC0006
  • Stainless steel construction
  • Internal ceramic substrate coating
  • EPA compliant
  • Long-lasting
Check Price
AUTOSAVER88 ATCC0007 AUTOSAVER88 ATCC0007
  • Great flow, minimal power loss
  • Heavy-duty, anticorrosive construction
  • EPA and OBD II compliant
Check Price
Walker 93253 Walker 93253
  • Features ceramic substrate
  • Durable stainless-steel construction
  • Does not trigger check engine light
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WATERWICH 2.25″ Universal Catalytic Converter WATERWICH 2.25″ Universal Catalytic Converter
  • EPA Complaint, 2 port both for Inlet/Outlet
  • More extensive than an original core hole
  • Enhanced gas exhausting
  • Reduced Back Pressure
Check Price
AUTOSAVER88 ATCC0026 AUTOSAVER88 ATCC0026
  • Simple DIY installation
  • EPA and OBD II compliant
  • 5-year, 50,000-mile warranty
Check Price

5 Best High Flow Catalytic Converters Review in 2021

Best High Flow Catalytic Converters

1. AUTOSAVER88 ATCC0006

AUTOSAVER88 ATCC0006 2.5

AUTOSAVER8 ATCC0006 is a universal, 400-cell catalytic converter made of stainless steel. This heavy-duty component keeps emissions at an all-time low while also maintain an optimal, steady flow rate. Inside of this high-flow cat is a coating of ceramic substrates, which keep internal reactions and structure running optimally.

The ATCC0006 features inlet and outlet diameters of 2.5 inches and measures in at 11 inches in length. The total weight of this high-flow cat is just under three pounds and doesn’t come with a hardware kit. The standard 2.5-inch inlet and outlet mean you don’t need to make very many modifications to set install this unit. However, if your car’s pipe is not the right size, and if you don’t have any experience in welding and cutting, you should consider hiring a professional mechanic to fit the unit onto your vehicle.

This high-flow catalytic converter is designed specifically for older vehicle models from 1996 and up. However, some users have installed this high-flow cat onto cars from the late-1980s with surprisingly satisfying results. While EPA and ODB II compliant, this high-flow cat is illegal to use in the state of California. If you reside in the golden state, this unit is sadly not for you.

Overall, this unit has left countless customers thoroughly satisfied. By replacing the stock converter of older vehicle models with the ATCC0006, you might be able to raise the horsepower of your baby girl with this catalytic converter.

What We Like:

  • Stainless steel construction
  • Internal ceramic substrate coating
  • EPA compliant
  • Made for cars from 1996 and up
  • Rarely triggers MIL indicator
  • Long-lasting

What Could Be Better:

  • Not CARB compliant
  • May require professional installation

2. AUTOSAVER88 ATCC0007

AUTOSAVER88 ATCC0007 2.5

One of the best high-flow catalytic converters for older cars is the ATCC0007. Like the ATCC0006, this unit (made by the same company) is a universal, 400-cell cat that can drop the emissions levels of cars made in the late-1990s and even some earlier models, according to customer feedback reports.

The 400-cell means larger holes to promote better flow, thereby sacrificing very little in terms of performance for emissions requirements. Installing the unit is as simple as the ATCC0006—it features 2.5-inch inlet and outlet diameters that connect to most standard exhaust pipes. However, you may need to welt and/or cut your exhaust pipe to make it fit with this unit. Leave this to the pros if you’re inexperienced in welding and operating a bandsaw.

The specific design of the ATCC0007 is made to prevent the MIL indicator from needlessly triggering. Plus, this high-flow cat comes with an O2 port that further improves the heating process of unburned exhaust fumes, thereby further improving emissions test results in old makes and models.

The exterior of this high-flow cat is made of durable stainless steel for long-lasting performance. This unit also uses the same ceramic substrate will undoubtedly work more effectively at converting harmful gases than your old car’s OEM catalyst.

What We Like:

  • Great flow, minimal power loss
  • Heavy-duty, anticorrosive construction
  • EPA and OBD II compliant
  • Additional O2 port for good measure
  • Fits most standard exhaust pipes with minimal cutting
  • Backed by 5-year warranty

What Could Be Better:

  • May require cutting and welding
  • Not CARB compliant

3. Walker 93253

Walker Exhaust Ultra EPA 93253 Universal Catalytic Converter

The Walker 93253 is yet another universal-fitting high-flow catalytic converter that is ODB II compliant. This unit will fit onto any vehicle made after 1996 and, as some customers claim, works wonders on cars made in the 1980s as well. This unit, like the previous ones, is not CARB compliant, so sadly, our Californian readers will have to look elsewhere.

This universal high-flow cat comes with a 2.5-inch inlet and outlet, so it’ll fit on the most standard exhaust pipes with minimal or no welding at all. Measure the diameter of your car’s exhaust pipe beforehand before settling on this particular model.

The exterior is made completely out of durable stainless steel, which, based on customer feedback, can last more than five years of heavy-duty driving. It features a similar ceramic substrate as the AUTOSAVER88 models, but the cell count figure remains unknown. That said, you don’t have to worry about this unit not passing emissions testing since it’s compliant with federal EPA regulations.

You will not find an O2 port in this unit, but with proper installation, you can reduce the amount of exhaust coming from your 30-year-old vehicle. Plus, this high-flow cat is specifically designed to prevent triggering your car’s MIL indicator.

Overall, the Walker 93253 is a great catalytic converter that works wonders and bringing older cars to life. At just 11.5 inches long, there shouldn’t be much trouble about fitting this unit onto your car’s exhaust pipe, though some welding might be necessary.

What We Like:

  • Excellent performance
  • Usable on older vehicles from the 1980s (per customer claims)
  • Features ceramic substrate
  • Durable stainless-steel construction
  • Does not trigger check engine light
  • EPA and OBD II compliant

What Could Be Better:

  • May require welding
  • Not CARB compliant

4. WATERWICH 2.25″ Universal Catalytic Converter High Flow without O2 Port for Inlet/Outlet

WATERWICH 2.25'' Universal Catalytic Converter

 

Let’s clarify: why did we choose this product o to include on our list? WATERWICH is a catalytic converter fitted with OE. The outer shell of this best high-flow catalytic converter is made using heavy-duty SS construction. So firstly, it is durable. Besides the durable outer layer, it has a precise internal metal loading to avoid Malfunction Indicator Lamp. Unlike any Lower Quality Converters, it is designed to ensure Excellent Flow Characteristics to give feedback even on an over OE.

Whereas other, regular converter generates the problem not to allow passes the gas efficiently, WATERWICH does it as much as needed. It is a high flow catalyst converter; that allows an enhanced flow of exhaust gasses. It also works by removing any other restriction to pass the gasses, so there is no chance get any impede function in the middle.

When can you pick this product? If you fear thinking an OE converter is not in a match with your engine power. This brand is for you. It’s a beautiful choice with good quality, which never will give any scope to see any issues. You will enjoy an excellent running of your car; even you will rarely need to check your engine light!

It is universal for vehicles, with a 2.25″ Outer Die Exhaust Pipe. Compared with the original core, it features a 1.5 to 2 times bigger size core hole. This unit not only gives efficient gasses exhausting, but it works to reduce Backpressure so that the car engine finally produces more horsepower.

You can call it is a Three-Way Catalytic Converter. It works to pass three harmful gases (CO, HC, and NOx) by oxidation-reduction and water-based gas reaction. Finally, it covers water as a final product.

What We Like:

  • EPA Complaint, 2 port both for Inlet/Outlet
  • More extensive than an original core hole
  • Enhanced gas exhausting
  • Reduced Back Pressure
  • Increase Engine Horsepowe

What Could Be Better:

  • Working efficiency should increase

5. AUTOSAVER88 ATCC0026

AUTOSAVER88 Catalytic Converter Compatible

Last up on our list of the best high-flow catalytic converters is another AUTOSAVER88 product—this time, it’s the ATCC0026. This is a unique cat in the sense that it’s a direct fit unit instead of universally fitting. This means that you weld it to keep in in place on exhaust pipes larger or smaller than 2.5 inches (the size of its inlet and outlet ports).

The flanges on either side of the ATCC0026 keep it snug in place during installation. A direct-fit high-flow cat like this one doesn’t require very much welding, if any, so you’ll have to make certain that the unit is right for your vehicle. It’s also OBD II compliant, so it’ll work great on cars from 1996 and up. This model is designed for Honda CR-Vs from 1997 to 2001, but if your car’s exhaust pipe is identical, then you shouldn’t have any problems.

Like other products on this list, the ATCC0026 is made of stainless steel with an interior ceramic substrate. There’s no cell rating on this model, but based on customer reports and considering its federal EPA compliance, there shouldn’t be any issues with emissions testing results.

Without an O2 port, you need to ensure that your vehicle’s sensors are in tip-top shape. Faulty sensors can result in damage to your vehicle’s spark plugs and quite possibly negatively impact fuel economy.

What We Like:

  • Direct fit, made specifically for certain vehicle types
  • Increases car performance
  • No MIL issues (if properly installed)
  • Simple DIY installation
  • EPA and OBD II compliant
  • 5-year, 50,000-mile warranty

What Could Be Better:

  • Non-CARB compliant
  • Only suitable for certain car models

All You Need to Know About High Best Flow Catalytic Converter

Here’s a quick overview of what you need to know about high-flow cats.

Know About High Flow Catalytic Converter

How High-Flow Catalytic Converters Increase HP

This might not always be the case. Unless your car’s engine has been packed with performance-upgrading features, you might not get the HP increase you’re looking for. On average, you can see a 5 to 60-HP increase.

  • Only heavily modified vehicles will experience a high HP increase
  • Average HP increase range between 5 and 60 HP
  • Regardless, high-flow cats will improve emissions ratings

Stock vs. High-Flow Catalytic Converters

In older vehicles, the main reason to upgrade to an aftermarket high-flow catalytic converter is to make it drivable by following modern emission laws. If your aim is to increase performance, especially in a new vehicle, the stock catalyst may suit you just fine.

  • Necessary upgrade for older vehicles
  • Better emission ratings than most OEM catalysts
  • Aftermarket can be more efficient than stock
  • Can boost power without affecting fuel economy

Advantages of a High-Flow Catalytic Converter

The advantages of these units range from increase vehicle performance and better emissions ratings. However, as we explained in an earlier section, the increase in performance depends on whether you’ve added performance-adding features to your car’s engine.

  • Possible HP increase
  • Less emission means a cleaner planet
  • You can drive your old super-polluting vehicles again
  • Less noise output
  • Can use high-performance fuels to power your engine

Important Q/A About High Flow Catalytic Converter

1. Why do I need a high-flow catalytic converter?

The stock cat on your car isn’t as restrictive as you might seem until you’ve modified your vehicle. In this case, you will need to upgrade your OEM to an aftermarket high-flow cat. Also, if you plan on driving a car made in the 80s or 90s, you have to get a new high-flow catalytic converter.

2. How long do high-flow catalytic converters last?

Their warranties generally last for up to five years or for 50,000 miles. However, the models listed above can last for upwards of seven years without showing any signs of trouble. That said, make sure you check the high-flow cat regularly to see that it’s not leaking exhaust or that it isn’t damaged in any way.

3. Can I salvage a dirty high-flow catalytic converter?

Sadly, you cannot. You can extend the life of your catalytic converter with regular cleaning, but after the ceramic substrate has become damaged beyond repair, your only choice is to replace it with a new unit. The good news is that you can sell the stainless-steel material. Some have sold their old high-flow cats for $50!

4. What are the effects of a bad/faulty high-flow catalytic converter?

With a dirty or improperly installed high-flow cat, your car will experience a noticeable drop in fuel economy. This can also happen to a dirty catalytic converter, so always make sure to give it a quick look on occasion to ensure it’s still performing optimally.

Final Verdict

In today’s guide, we’ve shown you what our picks of the best high-flow catalytic converters are. We’ve included both universal and direct-fit models, all of which come with 2.5-inch inlet and outlet ports. Do some research on your vehicle to see whether the models listed above are right for your car. Feel free to speak with a professional mechanic regarding the compatibility and installation (universal-fit) of your new high-flow catalytic converter.

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