Mk7 GTI OEM Downpipe - Upgrades, Benefits and Install Tips

Introduction to the Mk7 GTI OEM Downpipe

The Mk7 Volkswagen GTI debuted in 2013 as the seventh generation of VW's iconic hot hatch. Under the hood, it featured a new 2.0L turbocharged EA888 Gen 3 engine producing 210-220 horsepower. One popular modification for owners looking to extract more power is an aftermarket downpipe to replace the restrictive OEM downpipe.

The OEM downpipe on the Mk7 GTI connects the turbocharger to the rest of the exhaust system. It helps channel exhausted gases out of the engine. However, the factory downpipe was designed more for minimizing emissions and noise rather than maximizing power. An aftermarket downpipe with less restrictive bends and diameter can flow better and reduce turbulence. This allows the engine to breathe easier and make more power. Let's take a closer look at the Mk7 GTI's stock downpipe and the benefits of upgrading to an aftermarket one.

Stock Mk7 GTI Downpipe Design

The OEM downpipe on the Mk7 GTI consists of two main sections - the turbo outlet pipe leading from the turbocharger, and the intermediate pipe connecting to the rest of the exhaust. The downpipe diameter measures 2.25 inches on models with the Performance Package, and 2 inches on base models. Both sections are made from stainless steel for durability.

Performance-wise, the most restrictive part of the stock downpipe is the first 90 degree elbow coming off the turbo. This abrupt bend severely limits exhaust flow right from the start. There is also another 90 degree bend further downstream. In combination, these tight bends introduce turbulence that hampers exhaust flow and velocity.

Lastly, the OEM downpipe connects to the rest of the exhaust system using a 2-bolt flange. This makes replacing the downpipe more challenging compared to other models that use a 3-bolt flange.

Benefits of an Aftermarket Downpipe

Installing an aftermarket downpipe offers several benefits for the Mk7 GTI owner looking to increase performance:

Increased Horsepower & Torque

An aftermarket downpipe with smooth mandrel bent tubing, a larger diameter, and less restrictive Catalytic converter can allow the engine to flow better and make more power across the entire RPM range. Gains of 15-30 WHP are common with a proper tune.

Faster Turbo Spool

The improved flow also helps the turbo spool up faster, reducing turbo lag. The engine is able to reach peak boost sooner for a more responsive driving experience.

Enhanced Throttle Response

Beyond just peak power gains, an aftermarket downpipe also improves overall throttle response and acceleration by reducing exhaust backpressure. The engine can exhale more freely, allowing it to react quicker to throttle inputs.

Better Engine & Turbo Longevity

Reducing exhaust backpressure takes strain off the engine and turbocharger. This can help increase the lifespan of these components over time.

Added Sound

A nice bonus is the improved exhaust note with an aftermarket downpipe. It adds some deep tone and turbo spool noise to further enhance the driving experience.

Popular Downpipe Upgrades

Some popular downpipe upgrades for the Mk7 GTI include:

CTS Turbo Catted Downpipe

The CTS Turbo catted downpipe features smooth 3-inch mandrel bent piping, a high-flow catalytic converter, and CNC merge collector. It's capable of supporting over 500WHP.

APR Downpipe

The APR downpipe offers 3-inch stainless construction, smooth bends, and a 200-cell high flow cat converter. It's fully compatible with APR's ECU tunes.

AWE Tuning Downpipe

The AWE downpipe pairs T304 stainless steel with smooth stepped tubing for great flow. It retains the OEM catalyst and installs without having to modify the midpipe.

42 Draft Designs Downpipe

42 Draft Designs fabricates their downpipes from T347 aircraft grade stainless steel. They feature RF flanges and purge ports for clean install.

Downpipe Installation

Installing a new downpipe on the Mk7 GTI takes some mechanical skill and patience. With the right tools it can typically be completed in a few hours. Here are some installation tips:

Use a Lift

Having access to a vehicle lift makes the job much easier. If not, use jack stands and jack the front end up as high as possible.

Remove Battery

Disconnect the battery before starting work. This allows the ECU to reset and relearn properly with the new downpipe installed.

Unbolt Exhaust Components

Methodically unbolt the various exhaust components to reach the downpipe. Loosening the engine mounts helps provide wiggle room.

Transfer Sensors

Carefully remove the oxygen and temperature sensors from the stock downpipe and transfer them to the new one.

Modify Midpipe

Some downpipes may require modifying the midpipe by cutting off the stock flange and welding on a new one.

Bolt Everything Up

Once the new downpipe is positioned, bolt all the exhaust components back up from rear to front.

Get a Proper Tune

The ECU will need to be re-tuned with an appropriate off-the-shelf map or custom dyno tune. This ensures proper fueling and timing for the engine's newfound airflow.

Conclusion

Installing an aftermarket downpipe is one of the best bang-for-buck upgrades for the Mk7 GTI. The OEM part is quite restrictive, so changing it out for something less convoluted provides gains throughout the powerband. Just be sure to also get a compatible ECU tune to unlock the downpipe's full potential. With some simple hand tools and mechanical know-how, it can be a relatively straightforward DIY project.

FAQs

Does an aftermarket downpipe void my warranty?

Installing an aftermarket downpipe will likely void any powertrain related warranties. Downpipes are considered an emissions modifying part by most manufacturers. Check your warranty details before modifying the exhaust.

Will a downpipe cause my GTI to fail a smog test?

It depends on the specific downpipe. Some retain the catalytic converter and O2 bungs so they will likely pass. More racer oriented downpipes without cats will cause a smog failure due to lack of emissions control.

Do I need a tune with a new downpipe?

Yes, absolutely. The ECU needs to be re-tuned anytime major airflow changes like a downpipe are made, otherwise you risk engine damage from running too lean.

How difficult is it to install a downpipe?

It's recommended to have some mechanical skill and tools. Be prepared for a few hours job of jacking up the car, removing exhaust components, swapping downpipes, and reassembling everything.

Will a downpipe add exhaust noise?

Generally yes, most aftermarket downpipes will add a deeper and more aggressive exhaust tone, especially at wide open throttle. It also enhances the turbo spool sound.