The Upgrades for the Subaru WRX Downpipe

The Upgrades for the Subaru WRX Downpipe. Downpipes are one of the best turbo engine performance enhancements. There are numerous advantages to installing a downpipe improvement on a Subaru WRX. Downpipes are the first exhaust component after the turbo in force-induced engines, making them one of the most essential exhaust components. They are a component that can either throttle or substantially improve the performance of an engine.

A restrictive cat is used in the stock WRX downpipe, which is beneficial for emissions but not so good for performance. Fortunately, there are numerous upgraded WRX downpipes available in a variety of configurations to meet your requirements. In this tutorial, we’ll compare catless vs catted downpipes and go through some of the top Subaru WRX downpipe upgrades.

*Please keep in mind that this material only applies to Subaru WRXs manufactured between 2008 and 2021.

The Upgrades for the Subaru WRX Downpipe

What exactly is a downpipe?

A downpipe (DP) is the section of your exhaust that connects the turbocharger to the cat-back components. This section of the exhaust is exclusive to turbo engines. Most turbocharged cars, including the Subaru WRX engine, include a catalytic converter in the downpipe. In the case of VA WRXs, the downpipe has two cats. Because the cat immediately restricts exhaust flow after it exits the turbo, a lot of performance is lost. A downpipe is actually nothing more than that. It runs from the turbo to the cat-back and includes an OEM cat.

Because of its proximity to the turbo, it is the most significant component of a turbo engine’s exhaust. A downpipe provides the most performance increases when compared to the remainder of the post-turbo exhaust system.

Performance of the Subaru WRX Downpipe

The catalytic converter (cat) in the OEM WRX downpipe aids in emission reduction. It does an excellent job at this. Unfortunately, cats are also very restrictive, reducing power and performance. The pressure decrease from pre-turbo to post-turbo is critical to a turbo’s ability to spool. As a result, lowering back pressure after the turbo allows for faster spool and more power. On a turbo engine, no exhaust after the turbo is actually the best exhaust.

However, that is not a feasible plan for street cars. Catless and high-flow catted downpipe improvements come into play here. They will help to relieve back pressure and release up horsepower in the Subaru WRX engine.

Catless versus Catted Downpipes

Catless DPs are less restrictive because they remove the cat entirely from the downpipe. As a result, a catless Subaru WRX downpipe produces the most power, torque, and spool. However, catless downpipe options have a few drawbacks. A WRX with catless downpipes is unlikely to pass emissions tests. They’ll also make more noise and stench than catted downpipes.

The scent and sound variations are minor, so we wouldn’t be put off by them. Most people are probably most concerned about emissions. In this scenario, a catted downpipe is most likely the best option. If you’re not concerned about emissions or are ready to switch back to a catted downpipe for emissions testing, we strongly recommend going with a catless Subaru WRX downpipe. Without a doubt, they provide the best value for money.

High-flow DPs are frequently double the price and provide marginally less performance. High-flow downpipes use the same catalytic converter as standard downpipes but have a better design that optimizes exhaust gas flow. In general, high-flow downpipes provide less power than catless downpipes since exhaust gas must still pass through an additional component. They are, nevertheless, a wonderful option for individuals looking for extra power without potentially exceeding pollution restrictions.

The Upgrades for the Subaru WRX Downpipe

Pros of Subaru WRX Downpipe

Some advantages of running upgraded downpipes on a VA WRX include:

  • 10-20 horsepower (5-15 horsepower with cats)
  • Gains in torque are comparable.
  • faster turbo spool
  • Reduced back pressure and EGTs
  • Increased exhaust volume

The major selling point of Subaru WRX downpipe improvements is likely to be increased power. The advantages listed above apply to both catted and catless solutions. A catless downpipe, on the other hand, will outperform a catted DP in every way. With catless downpipes, expect to gain 10-20 wheel horsepower. Higher gains may be feasible with additional tweaks and optimization. In any case, WRX power improvements with a catted downpipe will be around 5whp less than with a catless downpipe. Torque gains will be about equivalent to power gains.

Because of the lower back pressure, the pressure drop will also help the turbo spool faster. This decrease in pressure also contributes to reduced exhaust gas temperatures (EGTs). Having said that, there are certainly numerous benefits to running an improved downpipe on the FA20 Subaru WRX.

Subaru WRX DP Catless Sounds

One of the most crucial aspects of upgrading a Subaru WRX is the sound. This is partly due to their incredibly distinct factory sound. The FA20F flat-4 boxer engine in the VA WRX provides the trademark “Subaru rumble” due to its arrangement. A WRX downpipe improvement can improve the pleasing rumble while also giving decent performance benefits.

In any case, a catless DP will lend a deeper, more aggressive note to a WRX’s exhaust. It’s most noticeable when starting cold or under strong power. Once the engine has warmed up, the idle will sound almost identical to stock (provided the rest of the WRX exhaust is factory). Furthermore, the DP sounds are difficult to notice while cruising normally. The point is that they provide a somewhat stronger exhaust tone without becoming annoyingly loud or invasive.

A catless downpipe combined with an improved WRX cat-back exhaust will produce the most noticeable overall sound. As a result, the overall diameter of your exhaust system will most likely be substantially greater, resulting in resonant noise. The power improvements from this combination are the best that a WRX exhaust system can provide. If you want to understand more about WRX exhaust choices, read our WRX Performance Exhaust article.

*Keeping with the pattern, high-flow DPs are noisier than stock but not as much as catless.

Upgraded Downpipe Options for the VA Subaru WRX

With that out of the way, let’s get started on some of our favorite Subaru WRX downpipe mods. We’ll go over some catless and catted DP alternatives. It should be noted that this is by no means an exhaustive list. There are numerous businesses that manufacture WRX aftermarket downpipes. These are just a few that we believe provide the best value for money in terms of price, quality, and performance.

1) 3′′ Catted Cobb Subaru GESi Downpipe

Price: $950.00

Cobb is an excellent choice for 2008-2015 WRX owners looking for a high-flow catted DP. Cobb’s purpose with this downpipe is to reduce exhaust turbulence as it exits the turbo, hence reducing excessive backpressure. The Cobb GESi is constructed completely of 304 stainless steel, which makes it incredibly sturdy and corrosion-resistant. It is a popular choice among WRX enthusiasts because to its established quality and performance.

The Cobb GESi 3″ Downpipe is ready to use right out of the box. The factory hard mount near the transmission is used in a welded bracket, minimizing stress on the turbocharger mounting bolts and studs. The downpipe’s back end has a heavy-duty flange that may take some abuse during installation. Using the provided gaskets, bolts, and studs, it can be fastened up to the factory WRX cat-back.

Because the Cobb GESi has a high-flow cat, performance is undeniably superior over stock. It will not, however, provide the same performance benefits as a catless downpipe. However, a catted choice will give you a considerably higher chance of clearing emissions. It is crucial to note that if you live in a state with stringent emissions restrictions, there is no assurance that this downpipe will pass.

2) Tomei WRX Catless Downpipe in Full Titanium

Price: $531.00

Tomei is a well-known aftermarket brand for Subaru vehicles. They have been making high-quality Subaru aftermarket parts for decades, much to the delight of the community. Their catless full titanium downpipe is no exception. According to Tomei, the major purpose of their full titanium downpipe is to deliver the highest performance part for throttle response and mid-range horsepower.

They capitalized on this goal by designing their downpipe to be as flow-friendly as possible and employing materials such as titanium, which decreases total weight without losing strength. The Tomei comes with all of the required hardware to get started right away. In terms of value for money, the Tomei is definitely the best buy in terms of a high-quality device that delivers the best performance.

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3) Catted GrimmSpeed Downpipe

GrimmSpeed is yet another well-known brand in the Subaru aftermarket scene. GrimSpeed, like Cobb and Tomei, is a well-known company that sells anything from downpipes to boost controllers. The GrimmSpeed downpipe is comparable to the Cobb mentioned above in terms of overall construction. Both are made of 304 stainless steel and have a single high-flow catalytic converter.

Fitment might be a difficulty with aftermarket exhaust components. Nothing is more infuriating than purchasing a new part only to discover that it does not fit with the stock hardware. To achieve a flawless fit, the GrimmSpeed catted downpipe was created using modern 3D scanning technology.

Overall, the GrimmSpeed Catted downpipe falls between in the middle of the Cobb and Tomei in terms of performance and pricing. The GrimmSpeed, at $839, is one of the most economical catted WRX downpipes available without sacrificing build quality.

Price: $839.00

Summary of Subaru WRX Downpipe Upgrades

Upgraded downpipes are a great mod for almost any turbo engine. That is also true of the Subaru WRX. Power improvements of 10-20whp are possible with a catless downpipe. High-flow catted DP’s should produce roughly 5 horsepower less. You’ll also notice faster turbo spool and a smoother power curve overall. Furthermore, catless and catted downpipes will give your WRX a slightly deeper, more aggressive sound.

Those looking for a catless downpipe will appreciate the Tomei Full Titanium catless downpipe’s low price, high quality, and performance. If you’re concerned about emissions, Cobb also offers a catted downpipe alternative. Nameless, Invidia, and a slew of other firms have some great options as well, although they are far more expensive. Regardless of your preference, Subaru WRX downpipe improvements are difficult to go wrong with.