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Parts Advisor

Sport catalytic converters

Why do you need a sports cat?
Bartek Bartoszewicz
Tuning Professional

It’s all about the sound: The sports cat

The sports catalytic converter is the first thing you think of for a good sound when tuning. But it does a lot more than that. Find out here why a racing cat makes sense in motorsport, how it works, and what it delivers. In addition, we let you into the secret of how to make it road-legal, and give you some tips on installing your cat.

What is a sport catalytic converter and how does it work?

The sport cat like a ‘normal’ series-production cat – ensures exhaust gas post-treatment in your car and reduces pollutant emissions. It converts combustion pollutants such as hydrocarbons, carbon monoxide, and nitrogen oxides into non-toxic substances: carbon dioxide, water, and nitrogen.

The sport cat usually consists of a metal honeycomb body – the carrier – which contains numerous thin channels. It features a special coating made from precious metals (platinum, palladium, and rhodium), the ‘washcoat’. While the exhaust gases flow through the catalytic converter, this coating carries out chemical conversion via oxidation or reduction, thus reducing your car’s emissions.

How is a racing cat structured in comparison to a standard cat?

In a sport cat, the number and structure of the channels, also referred to as cells, are reduced. This optimises the air flow and reduces exhaust back pressure. The pipe diameter of your racing cat is also larger than with the standard car to improve cooling. While standard cats are often made of ceramic, tuning cats are usually metal, with precious metal coatings. These are thus more robust and withstand the extreme performance we are working to achieve. They are produced through very elaborate processes. For one thing, the metal films that form the channels are connected to each other inside a vacuum furnace in order to ensure high strength and the intricate cell structure.

What are the benefits of a racing catalytic converter?

In addition to cleaning the exhaust gases, racing cats particularly boast improved performance and a sporty sound. Our metal cats consist of far fewer cells with thinner walls. The exhaust gas flow is drastically improved: our racing cats reduce the gas back pressure by up to 85 % compared to standard catalytic converters. This also lowers the thermal load on the engine and turbocharger through the optimized design, ensuring an increase in performance and durability. With a sports cat, you may even meet a better emission standard. Especially if you optimize your entire exhaust system, this will boost your car’s performance to the extreme: sports exhausts, sport mufflers, etc. increase your performance.

100, 200, 300, or 400 cells?

The number of cells in a catalytic converter always refers to the number of cells per square inch. For example, a 100-cell cat has 100 cells per square inch, while a 200-cell cat has 200 per square inch. While a standard cat often contains 400 or more cells, 100 to 200 cells are more generally used in motorsport. Sport cats with registration usually have 200 to 400 cells, since they still meet the exhaust standards during cold starting. The following rule generally applies: the fewer the cells, the greater the performance boost.

How does the registration of a sport cat take place?/h2>

If you wish to drive in road traffic, you need to obtain a registration. There are different options here:

  1. You buy a racing cat with an ‘ABE’ (general type approval). In most cases, you can install the part and then are approved for use in street traffic. If you aren’t sure, you can ask a pro.
  2. You buy a racing cat with a certificate of conformity. Then the catalytic converter will have a certificate of conformity, but you still have to take a short time to the TÜV. With this approach, the sport cat is entered in your car’s documents, which will entail extra costs.
  3. You buy a racing cat without any type approval or certificate of conformity. Here, there’s no way around an individual acceptance test by the TÜV. This is cost-intensive and may also fail. For this reason, we recommend always buying your cat with an ABE or certificate of conformity if you are driving with it on the road.
Sport Cat universal 200cpi EU4 Milltek

Delivery 5 to 8 days

Delivery 5 to 8 days

63,50 mm
70 mm
76 mm
+% more
200 cell sport cat
Diameter: 108mm
Length: 250mm
Connection diameter: 63.5, 70mm or 76mm


Why you should never use a dummy cat

In the tuning scene, the myth of dummy cats is making the rounds: they are said to additionally boost performance. But a myth is a myth. These fakes look like real racing cats, but they are hollow. They do not contain any cells and thus cannot clean exhaust gases. As a result, the oxygen sensor outputs incorrect values and the check engine light lights up. This can be reprogrammed through remapping, but that is not recommended. The missing catalytic converter means that your car does not meet the exhaust standard and you are evading taxes. This will void your insurance coverage and type approval, and your car can be taken out of service or impounded. Since you probably are investing a lot in your car’s performance, that would be a real nightmare. The solution lies in using a high-quality racing cat.

1.8T Passat 3b; 3BG & Audi A4 B5; B6 200 Zeller RENNKAT Plug&Play
1.8T Passat 3b, 3BG & Audi A4 B5, B6 High Flow Race Catalytic Converter Plug & Play

Immediate delivery!

Immediate delivery!

+% more
Reduced exhaust gas backpressure up to 85
Significant increase in performance
Relief for the turbocharger
EURO3 standard is fulfilled


Installation tips for your catalytic converter

If you want to install a universal tuning catalytic converter, you should observe these tips:

  • Choose your universal cat to suit the cylinder capacity, power, and exhaust standard. If you’re not sure how to proceed, feel free to ask us. We will give you a hand.
  • Prior to installation, check whether the air-fuel control, ignition system, and mixture formation are working correctly.
  • The reading direction of the number on the catalytic converter shows the direction of exhaust gas flow. That’s how you know what direction to install your racing cat in.
  • Be absolutely sure to install the cat in the correct position (close to the engine). And the oxygen sensor too. If your racing cat is shorter than the original part, supplement the missing piece with an additional pipe.
  • If there is heat protection on the original catalytic converter, your replacement cat will also need one.
  • Replace all connections between the cat, turbo, engine, and exhaust system when you install a sport cat.
  • Make sure that the entire exhaust system is installed without tension.
  • Check whether all connections are tight and cannot twist. Observe the information provided by the vehicle manufacturer regarding this and tighten all connecting bolts using a torque spanner.
  • Once everything is installed, start the engine, and check whether the connections are really tight. You should repeat this again after waiting a short time and, if necessary, tighten the bolts again.

No idea which cat is the right one or how to install it?

If you do not want to carry out the installation yourself and don’t know which catalytic converter is the right one for you, get in touch with us. We will advise you and take care of the installation.

Bartek Bartoszewicz
Tuning Professional
His first car was a Polo Mk1 with a 40 Weber twin carburetor and 129 PS (95 kW). His second was an Audi 50. Today Bartek tunes Lamborghinis to 1000 PS (735 kW). Even as a young boy, Bartek disassembled vehicles and put everything back together better. He wrote his high school diploma with oil on his fingers. The trained automotive mechanic with a focus on engines and gearboxes was determined to go into motorsports. In his 10 years in Formal 1, he supervised 73 races, including as engine mechanic for Ralf Schumacher at Toyota. Since 2010, he has dedicated himself fully to his company BAR-TEK® and helps his customers to bring VW and Audi engines to peak performance.
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05.02.2023, 18:35 Uhr
hey ich fahre einen 325 i e90 n52, ich habe mein auto vor kurzem ausgelesen und mir wirde angezeit das die kats fast am ende sind man riecht es auf ausserdem ist der wagen auch einfach lauter geworden ich wollte fragen ob ich mir ein sportlat zulegen kann der dann im strassenverkehr erlaubt ist und dementsprechen auch etwas lauter ? würde mich gerne beraten lassen.Ich kenne leider keine masse oder sonst was ich hab aber ein neuen endschalldämpfer von spower
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15.05.2024, 14:05 Uhr
Hi Eren, wir können dir diesen universal Kat anbieten: "" Die Maße vom Kat stehen in der Artikelbeschreibung. Kontaktiere bzgl. der Straßenzulassung am besten deinen lokalen Gutachter und sprich dich mit ihm ab, da wir nicht versprechen können, dass dein Fahrzeug mit deinem ESD und dem Kat TÜV bekommt MFG
Frank Schroeder
16.04.2023, 10:27 Uhr
Hallo, Ich muss 2 der 4 Kats im Chrysler Crossfire SRT6 ersetzten (vorderen 2). Eckdaten; 335 PS, 3,2 l Hubraum. Welchen Kat empfehlen Sie? Mit freundlichen Grüßen Frank Schroeder
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15.05.2024, 14:08 Uhr
Hallo Frank, wir haben uns auf Fahrzeuge des VAG Konzerns spezialisiert, daher können wir leider keine Empfehlung zu deinem Fahrzeug machen. MFG
21.08.2023, 17:12 Uhr
Hi I'm after a catalytic converter for a alfa romeo giulietta cloverleaf 2011. Could you please let me know on price and availability please Thank you Santino
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15.05.2024, 14:09 Uhr
Hi Santino, We specialise in vehicles from the VAG Group, so unfortunately we cannot make a recommendation for your vehicle. MFG
clive bonner
03.10.2023, 14:03 Uhr
I got a Audi RS5 2014 b8 which Catholic converted do I need for my car?
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15.05.2024, 14:19 Uhr
Hi Clive, it depends on what you are planning to do with your car. We have various universal catalytic converters on offer, you can view them in the sports catalytic converters category by clicking on the check mark under show universal parts. You may find something fitting for what your planning to do. Greetings