Catalytic Converter Upgrades Explained

Catalytic Converter Upgrades Explained

One of the most common performance upgrades fitted to modern vehicles are sports cats, racing cats, or upgraded catalytic converters. There are quite a few options when it comes to upgrading your cats, and it’s not always fully understood what these are:

Firstly what is a catalytic converter and what does it do?

A catalytic converter is part of the vehicle’s exhaust system, the cat itself looks much like an additional exhaust box fitted into the exhaust system close to the engine. It is in fact a chamber called a catalyst. Inside this catalyst chamber is a “matrix” a mesh which the exhaust gasses must pass through. This matrix is manufactured from complex metals, (which are semi-precious, and this is why thieves often steal them) As the exhaust gases pass through the matrix, a chemical reaction is triggered which changes the harmful compounds from an engine’s emissions into much safer gases, steam and carbon dioxide. It works to split up the unsafe molecules in the gases before they get released into the atmosphere.

So if catalytic converts are a good thing, why do people want to change them?

What are the benefits of a racing catalytic converter?

In addition to cleaning the exhaust gases, racing or sports cats boost a vehicle’s performance and also give a more sporty exhaust sound. The density of a catalytic converter is measured in “cells” a cell is the small gap in the matrix which allow the exhaust gases to pass through. The more cells you have in a square the denser the matrix is. Stock factory-fitted cats tend to be 600 – 800 cells, so there are a lot of cells per quester inch of the internal matrix. Sports cats tend to come in 400, 200 or 100 cell format. 100 cells being the most open and free-flowing option

200 Cell Catalytic Converter

When a cat has a lot of cells, like the 800 factory cells this can have the effect of reducing exhaust gas flow and will act a little like an additional exhaust silencer box. Adding restriction in the exhaust system. People in pursuit of more power and performance will often want to remove as many restrictions from the exhaust system as possible.

The exhaust gas flow can be significantly improved by as much as 85 % compared to an OEM cat. This also lowers the heat of the engine and turbocharger ensuring an increase in performance and durability.

So what performance catalytic convertor is best?

100, 200, 300, or 400 cells?

While a standard cat often contains 600 – 800 cells, 100 to 200 cells are more generally used in motorsport and sports. The following rule generally applies: the fewer the cells, the greater the performance increase.

Catalytic Converters

100 Cell Catalytic Converters

They may be the best for performance, but 100 cell cats may not be best for you. Though often used in motorsport 100 cell cats will generally not meet the criteria for the vehicles on board emission system. And therefore, are likely to trigger a check engine light situation. 100 cell cats may still pass road going emission testing if your engine is in good condition. But your vehicle systems may still detect the change and trigger an engine diagnostic fault code. As such 100 cell cats are often seen as off-road motorsport use.

200 Cell Catalytic Converters

200 cell cats are often seen as the sweet spot, fast flowing to allow the exhaust gases to pass quickly, boosting performance. But effective enough to not only pass vehicle emission testing. But also, enough to please the onboard systems and testing your vehicle performs all the time. Keeping that pesky check engine light off, and stopping your dashboard from lighting up like a Christmas tree.

To De-cat or not to De-cat?

The final option of course is to go all out and de-cat your car – removing the catalytic converter and matrix altogether and going for a complete free-flowing exhaust. This, of course, will give you the ultimate best performance and the loudest, and deepest exhaust tone.

BUT! And it’s a big but.

You will have to have your engine management software mapped to stop the vehicle emission systems from looking for and testing the cat that is no longer fitted.

In most countries, your vehicle will be deemed illegal for road-going use if the cat is removed. And your car will fail road-going emission tests. This may attract large fines or even vehicle confiscation in some countries.

And finally, without any cats fitted, the exhaust tone can become too loud for some owners especially if combined with a performance exhaust system. Annoying your neighbours and potentially attracting unwanted attention from the authorities.

VIEZU Exhaust systems and performance catalytic converters

VIEZU offer a huge range of performance exhaust systems and catalytic converters. Including 100 and 200 sports cats and de-cats pipes. The service and support team will be happy to make recommendations based on your vehicle’s use and your requirements.

Please contact the team for free, with no obligation and advice on how VIEZU can help you get the best out of your car. Contact Us