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As we know now more than ever, car manufacturers such as the Volkswagen Group, BMW and even Porsche are forever focusing on issues such as emissions / CO2 Output, environmentally friendly production and data and so on and so fourth.
One of the many ways this is achieved is by putting in the renwowned Catalytic Converter. The sole purpose of this?
Long story short, the gases from the exhaust goes in with the harmful chemicals, reactions happen and Water / Carbon Dioxide / Nitrogen come out.
What does the eye of a tuner see? Restriction and Restriction. For first, sound reduction – secondly, airflow reduction. Less airflow means less air / power can been pumped through the cars system. No good for those chasing the thrill of higher numbers.
This leads on to the ‘Decat Downpipe’. This bring the culmination of 3 words. Catalytic Converter Delete. (Re-arranged De-Cat!). Which in short, removes this converter to lift the restrictions!
Downpipes are a popular upgrade for car enthusiasts looking to get more power out of their engines. But what exactly are downpipes and what are their pros and cons?
The main benefit of decat downpipes is increased power. By removing the catalytic converter, the engine is able to produce more power due to the improved exhaust flow. This power can be felt in the form of increased torque and horsepower.
With the improved exhaust flow, the engine will also be able to run cooler, reducing the risk of overheating. Decat downpipes also give cars a more aggressive exhaust note, which can be a pleasant addition to a car’s sound system
On average, a car can gain around 20% additional power (of the original power) when this modification is done depending on the platform being tuned. When it comes to the biggest gains, you usually see this on Platforms with turbos such as the likes of AMG BiTurbos or BMW’s B58’S. (Of course, the gain also ties in from the other factors, ie turbo, spark plugs, torque limiters etc.)
Have a look here to see how this C63 Sounds with no catalytic converters!
So once we’ve gone ahead and installed the parts of the car its time for the main show. The Remapping.
By doing the downpipe upgrade (on petrol cars) you’ve now set yourself up for Stage 2 Tuning. As we mentioned prior this would make your car performance be boosted by around 10-20% from what it was out of the showroom floor.* The alternative is Stage 3 but then we are talking turbo, fuel pump injectors at that point.
Let’s keep it simple with the downpipe for now.
A great example of this simple setup for power with the AMG GT63s and MK7 Golf R we tuned! From the factory, this car is 639BHP with 900Nm of Torque. With the upgraded downpipe and our Stage 2, we took it to 780BHP with 1,100Nm of Torque. Around an 11% Increase in power here!
From there, you can only go up in power when you begin your walk to Stage 3+ which we will talk about in another Blog!
The increased noise may also turn heads on the street and give the car a unique presence.
However, there are also some drawbacks to decat-downpipes.
The increased exhaust flow can cause issues with the car’s emissions system, leading to higher levels of pollutants being released into the atmosphere. This can be a serious environmental concern and may even lead to legal troubles in some areas.
Additionally, decat downpipes are not legal in all areas due to the increased emissions levels. In some areas, these modifications may void the car’s warranty or lead to fines or other penalties. Overall, decat downpipes are a great upgrade for car enthusiasts looking to get more power out of their engines.
However, they should be used with caution, as they may lead to increased emissions levels and may not be legal in all areas. If you’re considering a decat downpipe, make sure to do your research and check with your local regulations to ensure that you are following the law.
1- Gains. You can gain much higher torque and power on turbo’d platforms. Subject to car and engine capability of course.
2 – Sound. A decat system reforms the way your car will sound. Deeper punch, much louder sound when giving the car its all. You won’t be dissaponited.
3 – Emissions. With the downpipe, emissions are void. Meaning you will have a failed MOT.
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Any modifications or software calibrations that result in a vehicle no longer complying with DVSA road regulations or applicable road traffic laws are supplied for off-road and track use only. It is the vehicle owner’s responsibility to ensure compliance with all relevant laws and regulations when operating the vehicle on public roads.
make your german sound like a true race car. enquire for a valvetronic design system today!