Guide on Downpipes for 1.8T 20V Engines

Posted by admin On August 25, 2012 ADD COMMENTS

VAG 20V 1.8T Downpipe Guide

This blog post is about the stock downpipes and what options there are to upgrade them for the different types of the 1.8T engine.

So there are essentially 6 different stock  downpipe types for 1.8T 20V engines:

  • Transverse FWD – K03 – Front Wheel Drive – VW Mk4 – Golf / Audi A3 8L / Skoda Octavia / Seat Leon 1M / Audi TT 8N

OEM Piping Size : ~57mm


SPLITS IN ~~  ->2000->

  • Transverse FWD – K03 – Front Wheel Drive – Seat Ibiza / VW Polo

OEM Piping Size : ~55mm

  • Transverse 4WD – K03 180HP – All Wheel Drive (Haldex) – Audi A3 8L / Audi S3 8L / Seat Leon 1M / Audi TT 8N

OEM Piping Size :  ~57mm

  • Transverse 4WD – K04 210HP / 225HP – All Wheel Drive (Haldex) – Audi A3 8L / Audi S3 8L / Seat Leon 1M / Audi TT 8N

OEM Piping Size :  ~ 70mm -> 2 x ~45mm

  • Longitudinal FWD / 4WD – K03 – Front Wheel Drive + All Wheel Drive – Audi A4 B5 / Audi A4 B6 / VW Passat 3B / VW Passat 3BG

OEM Piping Size : ~60mm

The upgrade!

So now we have looked at the OEM stock downpipes, which is the restrictive part we want to improve.

Each type of downpipe is partly a Catalytic Converter / partly a piping size.

Catalytic Converter has a cell construction inside, in which the flow is intended to flow through and get filtrated to delete exhaust particles to prevent polution.

The piping size is related to extended volume – meaning less backpressure in the downpipe. This allows the turbocharger to work more easily resulting in quicker response and more power. The bigger the better!

You can get catalytic converters, which is flowing more than stock – but still maintain the Euro level which these cars are born with.

You would want to buyEuro level cats of

Euro 4 for models after 2000

Euro 3 for models before 2000

To get the best optimized flow flow, you would normally want a Catalytic Converter with a Cell amount between 200 Cell – 400 Cell.

The higher the cell amount – the easier the exhaust gasses are deleted to the level of Euro emissions.

For the below cases there will be focus on upgrade downpipes without the catalytic converters.

The catalytic converter can be added afterwards or you can buy complete ready downpipes with catalytic converters for your application.

Below is a listing of the options on the market for upgrade downpipes for the 1.8T models.

If something is left out, i encourage you to send me an email and it will be added eventually.

150 / 180HPTransverse – FWD
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Megan Racing63mmLow
150 / 156 / 180HPTransverse – Polo / Ibiza
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180HPTransverse – 4WD
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210 / 225HPTransverse – 4WD
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150 / 163 / 180HPLongitudinal – FWD/4WD
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So what should you choose out of the models available for your car ?

The different models have pricelevels depending on the effort and work put into making them.

The cheapest model might not be the best bang for the buck and the most expensive may not be the ultimate upgrade.

If you want to know more about upgrading the parts on the 1.8T Engine or other VAG engines, follow the blog, which will give you news and articles about how you best choose and what you should look for when you are making choices for upgrading the parts on your own car.

Find out more about 1.8T 20V engines in this page:

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