HOW TO CHOOSE THE RIGHT MINI CATALIZADOR®

Choosing the right Mini Catalizador® is simple. Just follow these 3 steps:

01

CHECK YOUR O2 SENSOR THREAD

Mini Catalizador® O2 sensor spacers use a universal M18 × 1.5 thread and are designed for most vehicles with a threaded downstream (post-cat) O2 sensor.

IMPORTANT:

The spacer must be installed on the downstream/post-cat O2 sensor, not the upstream/pre-cat O2 sensor.

02

CHOOSE THE RIGHT ANGLE

Choose the angle based on the available space around your downstream O2 sensor:

Straight (180°)
Best when there is plenty of space around the O2 sensor.
45°
A good choice when moderate clearance is needed.
45° Pro
Same 45° angle, but with a larger internal catalytic core for stronger performance.
90°
Ideal for tight spaces and our most popular option.
90° Pro
Same 90° angle, but with a larger internal catalytic core for stronger performance.
TIP:

Not sure which angle to choose? The 90° version is usually the easiest choice when space is limited.

03

CHOOSE THE CORRECT QUANTITY

The number of Mini Catalizador® spacers you need depends on the number of downstream/post-cat O2 sensors on your vehicle.

Install 1 spacer for each downstream/post-cat O2 sensor.

1 downstream O2 sensor → 1 spacer
2 downstream O2 sensors → 2 spacers
COMMON EXAMPLES:
  • Many 4-cylinder vehicles typically have 1 downstream O2 sensor → 1 spacer.
  • Many V6/V8 vehicles have 2 downstream O2 sensors, usually one for each bank → 2 spacers.
WHAT ABOUT P0420 OR P0430?

P0420 and P0430 are catalytic-efficiency-related trouble codes. They can help identify which bank is reporting the issue, but the code alone does not determine how many spacers you need.

The safest way to choose the quantity is to count the downstream/post-cat O2 sensors on your vehicle.

  • P0420 → Bank 1 Catalytic Efficiency Below Threshold
  • P0430 → Bank 2 Catalytic Efficiency Below Threshold

If your vehicle has both P0420 and P0430 and has 2 downstream O2 sensors, you will typically need 2 spacers — one for each downstream O2 sensor.

QUICK GUIDE

Thread:
M18 × 1.5
Installation Position:
Downstream / Post-Cat O2 Sensor
Quantity:
1 spacer per downstream O2 sensor
Angle:
Choose based on available clearance

Not sure which angle? → 90° is the most popular choice for tight spaces.

Check Engine Light Still On?

We have helped many customers resolve catalytic efficiency codes such as P0420/P0430 with our O2 sensor spacer. In most cases where the CEL remains on, it is usually related to installation position, spacer adjustment, exhaust leaks, ECU relearning time, or the condition of the rear O2 sensor.

Before making any changes, please go through the steps below one by one:

01 Check the Installation Position

First, please make sure the spacer is installed on the rear/downstream O2 sensor only (the sensor located after the catalytic converter).

The spacer should NOT be installed on the front/upstream O2 sensor, since the front sensor controls the air-fuel mixture. Installing it on the front sensor can cause additional engine codes.

02 Confirm the Number of Spacers

Next, confirm that the correct number of spacers are installed:

  • 1 rear O2 sensor = 1 Mini Catalizador
  • 2 rear O2 sensors = 2 Mini Catalizadores
03 Check the Installation Depth

Please also check the installation depth. The spacer should not be screwed too far into the exhaust pipe.

On some vehicles with smaller exhaust pipes, the end of the spacer may sit too close to the inside wall of the pipe, which can affect exhaust flow and O2 sensor readings. The included lock nut can be used to control the depth and prevent the spacer from going too far into the exhaust pipe.

04 Check for Exhaust Leaks

After that, please check for any exhaust leaks around the O2 sensor or catalytic converter area. Even a small leak can cause incorrect sensor readings and keep the CEL on.

05 Clear the Codes & Allow Relearning

Once everything is checked, clear the trouble codes or reset the ECU and drive normally for about 20–50 miles. Some vehicles may require several drive cycles before the ECU completes its monitoring process.

06 Additional Rear O2 Sensor Codes

If you are seeing additional rear O2 sensor performance codes after installation (such as slow response or abnormal O2 readings), some vehicles—especially modified vehicles, high-performance vehicles, or vehicles with more sensitive ECU calibration—may react differently to the mini catalytic insert.

In this situation, you can test the spacer without the mini catalytic insert:

For 45° and 90° models:

  • Remove the mini catalytic insert and reinstall the spacer without it.
  • Or remove the Mini Catalizador head completely and use only the bottom extension tube.

For 180° models:

  • Remove the mini catalytic insert from inside the unit and reinstall the spacer without it.

This keeps the rear O2 sensor relocated while allowing a more normal exhaust flow path, which may help with slow or abnormal rear O2 sensor readings.

07 Check the Rear O2 Sensor Condition

Finally, if the CEL still remains after checking all of the above, the rear O2 sensor itself may be the reason. Older or contaminated O2 sensors can become slow to respond and continue sending incorrect readings to the ECU even after the spacer is installed.

Frequently asked questions

Questions? We Have Answers

Yes, all of our products come with free shipping. Our logistics support team can deliver O2 Sensor Spacer worldwide.

When you add an item to your cart, there is a "Special Requests or Comments" box in the cart interface. Please write your request as clearly as possible, and we will do our best to accommodate it. If you can't find the input box, you can also email us. Be sure to include your order number and special request in the email, and please remember to contact us before we ship your order.

You can pay by credit card, debit card, bank account, or PayPal. About the payment method: Click to Visit

Taxes and VAT are included in the prices when ordering. Any additional charges, taxes, or brokerage fees by your local government are the responsibility of the recipient. Keep in mind that there is a small chance that you will get charged VAT or duties; however, if you do get charged, we cannot be responsible for these fees in any way, as we do not receive any of this money. The funds go exclusively to your government. The last thing we would want is for our customers to be charged extra. Since duties and taxes vary by country and by what was ordered, we are not able to supply an estimated cost. Please contact your customs office for more information. Shipping & handling fees, administration fees, and taxes (50% of the total order value before discounts) will not be refunded for packages that are refused due to VAT/duties. If your situation wasn't mentioned in our refund policy, make sure to send us an email at support@minicatalytic.com, and we will help you resolve it as soon as possible!

We will deliver the goods within 24 hours after receiving the order and arrive within 2-7 working days.

We currently do not offer expedited services. However, if your order is urgent, please contact our customer service team, and we will do our best to make special arrangements.

Orders ship from Monday to Saturday excluding US Federal holidays.
Orders received before 1:30 PM Eastern Standard Time will be processed within the same business day, provided that the goods are in stock and customer identification is verified.
Delivery to Alaska, Hawaii and Puerto Rico may be delayed.

Under normal circumstances, items are shipped through local carriers in each country, such as USPS in the United States, Australia Post in Australia, and Royal Mail in the UK. You can track your shipment here: https://www.minicatalytic.com/pages/track

After your order is shipped, you will receive a shipment notification email (sent to the email address you provided during purchase). This email will provide the shipping date, the items shipped, the tracking number, and a link to track your shipment.

If you want to change your order you must contact us within 12 hours of placing the order. Go to contact us and send us message requesting the specifications of the change.

Once your order has been submitted, we will mail you the product immediately. If you would like to cancel your purchase, please contact us to cancel your order.

90-day Postage Paid Returns

Refund & Return Policy

We apologize for any inconvenience if you are missing items from your order or received the incorrect item. Please contact Customer Care Team immediately to resolve the issue.

If you have any issues with your address, make sure to contact us as soon as possible by sending us an e-mail to support@minicatalytic.com so that we can move swiftly to correct the problem.

For any reason, if you are not completely satisfied with your purchase, you can return unused products in original condition within 90 days of purchase. You don't like our products. The received products are damaged and affect the use.

Contact customer service email:support@minicatalytic.com to explain the reason for return. We will guide you how to process the return.
Put the goods into the gift box And protect the package for mailing.
Drop off package at your nearest USPS Store, USPS Authorized Shipping Outlet or USPS Customer Center. You need to pay the returned fee.
All returns will be credited back to the original form of payment (excludes original shipping cost)

You can only return items that are unworn, unwashed, undamaged, have the original tags/packaging attached.

The product has been used or worn won't be refunded.
No refund for more than 90 days after receiving the product.

Due to additional quarantine measures around return shipments, please allow up to 5 business days, from the receipt of your return package, to process your returns. You will receive an email notification once your return is processed. Please allow up to 5 additional business days for the funds to be credited to your payment method.

Frequently Asked Questions about Using O2 Sensor Spacer

People also ask

A new O2 sensor spacer differs from the older version in that it integrates a mini catalytic converter within the spacer. This new design works similarly to larger catalytic converters, where harmful exhaust gases pass through a ceramic honeycomb element coated with platinum, rhodium, and palladium. These materials help oxidize and convert harmful pollutants in the exhaust gases. Inside the honeycomb, a chemical reaction takes place, transforming the pollutants into harmless carbon dioxide (CO2) and water (H2O), while also converting nitrogen oxides (NOx) back into nitrogen (N2) and oxygen (O2).

Our new O2 sensor spacer not only converts harmful emissions but also sends the expected exhaust readings to the ECU, ensuring that the ECU operates optimally to produce additional horsepower. This helps to eliminate the Check Engine Light (CEL) caused by incorrect O2 sensor readings, improving both engine performance and emissions efficiency.

The new O2 sensor spacer with a built-in mini catalytic converter is specifically designed to address CEL issues caused by high-flow catalytic converters (HIFLOW Cat) or deleted catalytic converters in the exhaust system. By adjusting the position of the O2 sensor, it makes the ECU believe there is a properly functioning catalytic converter in the exhaust system, which typically helps eliminate P0420 and P0430 error codes.

The built-in mini catalytic converter works similarly to a traditional catalytic converter, converting harmful exhaust gases into harmless substances, effectively "tricking" the ECU into thinking the catalytic converter is still working. This is especially suitable for vehicles with modified or removed original catalytic converters.

Although this product is effective in most cases at resolving CEL issues caused by O2 sensors, results may vary depending on exhaust system layout, ECU tuning, and specific vehicle modifications. Therefore, it cannot be guaranteed to resolve the issue for all vehicles.

The new O2 sensor spacer is equipped with a mini catalytic converter that features a ceramic honeycomb structure coated with platinum, rhodium, and palladium. This mini converter effectively oxidizes and transforms harmful emissions.

Through catalytic reactions, it converts carbon monoxide (CO), nitrogen oxides (NOx), and hydrocarbons (HC) found in vehicle emissions into harmless carbon dioxide (CO2) and water (H2O). The precious metals—platinum, rhodium, and palladium—act as catalysts in this process, reducing the emission of harmful gases. By simulating the function of a full-sized catalytic converter, the O2 sensor spacer ensures that the O2 sensor receives the expected exhaust data, which in most cases clears the check engine light (CEL).

The new O2 sensor spacer is designed for O2 sensors with M18 x 1.5mm threads, which covers 99% of O2 sensor threads. It is compatible with a wide range of vehicles, including BMW, Audi, Toyota, Nissan, Volkswagen, Subaru, Honda, and more, fitting engines from 1.6L to 6.3L, both turbocharged and non-turbocharged.

The product is made of high-quality T-304 stainless steel, ensuring it is rust-resistant, corrosion-resistant, peel-free, and flake-free. It has excellent high-temperature durability, capable of withstanding working temperatures up to 620°F (approximately 327°C), making it suitable for long-term, high-temperature environments. Unlike alternatives made from zinc-plated carbon steel or filled with steel wool, our O2 sensor spacer is entirely constructed from T-304 stainless steel, which will not experience coating peeling or rusting at high temperatures. This ensures long-lasting, reliable performance, making it the ideal solution for O2 sensor issues.

Installation is very simple and quick, typically taking no more than 10 minutes. Just screw the new O2 sensor spacer onto the existing O2 sensor, then reinstall it into the O2 bung. No welding, soldering, or wiring is required, and it can be easily removed at any time if necessary.

For vehicles with a dual exhaust system or V6/V8 engines, two new O2 sensor spacers are typically required (one for each exhaust pipe). Each exhaust pipe has a post-cat O2 sensor (located after the catalytic converter), so one spacer is needed for each O2 sensor to ensure the exhaust system operates correctly and to prevent triggering the check engine light (CEL). If your vehicle has a single exhaust system, only one spacer is needed.

The new O2 sensor spacer is available in three angle options: 0° (straight), 45°, and 90°, and is compatible with all vehicles equipped with M18 x 1.5mm O2 sensor bungs. The choice of the appropriate model typically depends on the space available at the O2 sensor location. If the exhaust system has tight or hard-to-reach spaces, a 45° or 90° spacer may be more suitable. Please select the angle based on your vehicle’s exhaust system layout for the best fit during installation.