On a turbo engine the downpipe is the first section of exhaust for the turbo and at the same time the most restricted part of the factory system. That is why most tuners do this upgrade right after a software remap, and often together with it.<\/p>\n\n\n\n\n\n
In this guide we explain what a downpipe is, what it really brings, the three types available and how to choose between decat<\/strong>, a sports catalytic converter<\/strong> and the approved version<\/strong>. The prices come from our range, where we currently have more than 600 downpipe and GPF delete kits<\/a> for VAG, BMW, Ford, Hyundai, Mini, Mercedes and others.<\/p>\n\n\n\n\n\nTC VAG downpipe for 1.8\/2.0 TSI: 3-piece stainless steel design with a flex section, lambda bung and clamp\n\n\n\n\n\n The downpipe is the pipe connecting the turbo outlet to the mid section of the exhaust. The exhaust gases pass through it immediately after driving the turbine wheel. This is where the temperature is highest and every restriction in the pipe slows the turbo the most.<\/p>\n\n\n\n\n\n The factory downpipe has a narrow diameter, sharp bends and a built-in primary catalytic converter. On newer petrol engines (Euro 6d, from roughly model year 2018 onwards) there is also a GPF or OPF particulate filter after the catalytic converter. All of that reduces flow and creates back pressure the turbo has to work against.<\/p>\n\n\n\n\n\n A performance downpipe has a larger diameter (usually 3\u2033, i.e. 76 mm), smooth transitions, stainless steel and, instead of the factory catalytic converter, either nothing, a sports cat or an approved sports cat. These are also the three types we describe below.<\/p>\n\n\n\n\n\n Important: with a decat and with most sports cats the engine warning light will come on without a software adjustment (fault P0420). The rear lambda sensor no longer sees the catalytic converter it expects. A remap fixes this and at the same time makes use of the extra flow.<\/p>\n\n\n\n\n\n You choose a downpipe mainly by what replaces the factory catalytic converter inside it. That determines the price, the power, the sound and whether the thing is road legal at all.<\/p>\n\n\n\n\n\n An empty pipe with no catalytic converter at all. The most flow, the loudest sound, the lowest price. It is intended solely for track use and is marked by every manufacturer as motorsport only<\/em>.<\/p>\n\n\n\n\n\n Examples from our range: TC VAG downpipe for 1.8\/2.0 TSI (Golf VII GTI, A3 8V, Leon 5F, Octavia 5E; inox, 3\u2033, with lambda sensor port, 379 \u20ac), TC B58 downpipe for BMW (299 \u20ac), TA Technix downpipe for Golf VII \/ A3 8V \/ Leon (261 \u20ac) and Milltek decat for Golf 7 and 7.5 (804 \u20ac).<\/p>\n\n\n\n\n\n It has a high-flow catalytic converter with 200 or 300 cells per square inch (cpsi). The factory one has 400 to 600 and more, so a sports cat keeps most of the flow while still containing some of the emissions and smell. The sound is more civilised than with a decat.<\/p>\n\n\n\n\n\n Examples from our range: Wagner Tuning 200 cpsi for VAG 1.8\/2.0 TSI<\/a> (1.020 \u20ac), Wagner Tuning 200 cpsi for BMW N55<\/a> (910 \u20ac), Milltek with a sports catalytic converter for Leon and Golf 7<\/a> (776 \u20ac) and Scorpion 5\u2033 with a sports catalytic converter for BMW F20\/F22<\/a> (998 \u20ac).<\/p>\n\n\n\n\n\n A sports catalytic converter with paperwork. Milltek HJS ECE downpipe<\/a> uses a catalytic converter from the German manufacturer HJS and has ECE approval. This is the only version you can have entered in the vehicle documents and take through the technical inspection without worry.<\/p>\n\n\n\n\n\n We currently have 20 kits, among them for Audi S3 8Y, TT and Cupro Formentor<\/a> (3.312 \u20ac), BMW G20\/G21\/G42<\/a> (2.227 \u20ac), Ford Focus MK3, Hyundai i30 N, Mini F56, Toyota Yaris and Seat Leon. You will find them all using the filter T\u00dcV certificate: YES<\/strong> in the downpipe kits category.<\/p>\n\n\n\n\n\n On petrol engines from roughly 2018 onwards there is also a particulate filter (GPF or OPF) after the catalytic converter. It is even more restrictive than the catalytic converter itself, so on these cars the downpipe often replaces both parts. Such kits are marked in our range as GPF Delete<\/strong> and, like a decat, they are for track use only.<\/p>\n\n\n\n\n\n Examples: Scorpion GPF delete for Golf R 7.5 and S3 8V<\/a> (836 \u20ac), GPF delete for Hyundai i30 N<\/a> (\u20ac165, with a before\/after video) and TC downpipe for EA888 Gen4<\/a> (Golf 8 GTI, Leon 4, Formentor; 379 \u20ac).<\/p>\n\n\n\n\n\n If you want to stay legal on such a car, leave the filter in place and sort the sound with a GPF-back system<\/a>, which replaces the exhaust from the filter back.<\/p>\n\n\n\n\n\n The short, honest answer: a decat no, a sports cat without documents no, an ECE-approved one yes, but only after it is officially entered in the vehicle documents. A certificate in the glovebox is not enough. We described the whole procedure, what T\u00dcV and ECE marks mean and where the entry is made, in the guide to type approval for performance exhausts in Slovenia<\/a>.<\/p>\n\n\n\n\n\n Every product in the shop clearly states whether it comes with documentation for road use. If you are not sure, write to us before ordering.<\/p>\n\n\n\n\n\n The fastest way to the right part is via the page for your car, which shows only the products that fit: VW Golf VII<\/a>, Audi A3 8V<\/a>, Seat Leon 5F<\/a>, BMW 3 F30<\/a>. For other models use the vehicle selector at the top of the page.<\/p>\n\n\n\n\n\n No. On its own a downpipe brings little power, and the warning light for and with a decat and most sports cats the engine light will almost certainly come on. It is the Stage 2 remap that turns the extra flow into power and at the same time adapts the lambda sensor monitoring.<\/p>\n\n\n\n\n\n It depends on the engine and the remap. On modern 2.0 TSI and BMW B58 engines the downpipe is exactly the prerequisite for a Stage 2 remap, which compared with Stage 1 brings a few dozen more horsepower and noticeably more mid-range torque. The exact figures will come from the tuner who writes the map.<\/p>\n\n\n\n\n\n A decat does, noticeably, and adds pops on overrun. A sports cat deepens the sound but does not make it much louder. An approved HJS downpipe is closest to the factory part in volume, as it has to stay within the permitted limits.<\/p>\n\n\n\n\n\n The downpipe is the section from the turbo to the catalytic converter (or including it), while cat-back is everything from the catalytic converter back: mid silencer, rear silencer and tips. A cat-back mainly affects sound and looks, while a downpipe affects power. Together they make up a complete performance exhaust.<\/p>\n\n\n\n\n\n In a workshop usually 2 to 4 hours, depending on access to the turbo and how many factory bolts have rusted. On engines where the turbo is jammed against the firewall (a transverse VAG, for example), expect the upper end of that range. The software calibration follows the installation.<\/p>\n\n\n\n\n\n The downpipe is the single most effective exhaust upgrade on a turbo engine and the foundation of every Stage 2 build. For track use take the decat, for everyday legal driving, an ECE-approved HJS downpipe, for the middle road, a sports cat, knowing what that means at the technical inspection.<\/p>\n\n\n\n\n\n You will find all three types in the category Downpipe and GPF delete kits<\/a>. If you are not sure which one fits your engine, write or call us<\/a>. We will check fitment and availability before you order.<\/p>\n\n\n\n\n\n Read also: Type approval for performance exhausts in Slovenia<\/a>, VAG EA888 Gen3 tuning guide<\/a>, How to choose the right blow-off valve<\/a> and Uses and benefits of heat wrap for exhaust<\/a>.<\/p>\n\n\n\n\n\n If you haven\u2019t already, you can sign up for our newsletter using the form below. You can expect more articles like this in your inbox, plus other news from the car world, such as upcoming car meets, track days and other events.<\/p>\n\n\n\nWhat is a downpipe and where does it sit in the exhaust?<\/h2>\n\n\n\n\n\n
What does a downpipe bring in practice?<\/h2>\n\n\n\n\n\n
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Which three types of downpipe are there?<\/h2>\n\n\n\n\n\n
1. Downpipe without a catalytic converter (decat)<\/h3>\n\n\n\n\n\n
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2. Downpipe with a sports catalytic converter (200 or 300 cpsi)<\/h3>\n\n\n\n\n\n
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3. Approved downpipe with ECE certification (HJS)<\/h3>\n\n\n\n\n\n
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What about a GPF\/OPF delete on newer cars?<\/h2>\n\n\n\n\n\n
Will a downpipe pass the technical inspection?<\/h2>\n\n\n\n\n\n
How to choose the right downpipe for your car?<\/h2>\n\n\n\n\n\n
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What else to upgrade along with the downpipe?<\/h2>\n\n\n\n\n\n
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Which downpipe brands do we stock?<\/h2>\n\n\n\n\n\n
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Frequently asked questions about downpipes<\/h2>\n\n\n\n\n\n
Is a downpipe worth it without a remap?<\/h3>\n\n\n\n\n\n
How much power does a downpipe bring?<\/h3>\n\n\n\n\n\n
Is a downpipe louder?<\/h3>\n\n\n\n\n\n
What is the difference between a downpipe and a cat-back system?<\/h3>\n\n\n\n\n\n
How long does fitting a downpipe take?<\/h3>\n\n\n\n\n\n
Conclusion<\/h2>\n\n\n\n\n\n