Evo X Downpipe Upgrade
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One of the most popular mods for the Evolution X is a downpipe. An Evo X downpipe upgrade is a great way to boost horsepower, torque, and improve turbo spool and responsiveness. In the following guide, we will look at what benefits you can get from upgrading your downpipe, followed by a list of our recommendations for top downpipes on the market. Make sure to check out our other Evo content, including Evo X coilover upgrades, Evo X intake upgrades, and the Top seven mods for the Evo X.
Widemouth vs Divorced Downpipes
For an Evo X downpipe upgrade there are two basic options: Either widemouth or divorced style. Both of them offer similar flow and performance as each other, and sound decibel-wise they are also similar. The difference between them is how they connect to the turbocharger.
A divorced style downpipe (see below) has two different tubes — one significantly narrower than the other — that both connect to the turbo. The larger tube covers the turbine outlet and the smaller tube (or “dump tube”) covers the wastegate outlet. They both eventually merge together towards the middle of the downpipe. This is compared with a widemouth-style downpipe, which covers both the wastegate and turbine outlets with a single exit and only consists of one large tube.
The purpose behind a divorced style downpipe is to reduce boost creep and lessen potential turbulence in the exhaust flow. By allowing for two smaller exits instead of one larger one, the flow can be controlled better and more smoothly.
Widemouth designs have been known to be prone to boost creep, which is where the turbo continues to build boost even when it should be tapering down. This is problematic because the engine can run in a lean condition if boost can’t be controlled, causing detonation and pre-ignition. This winds up potentially leading to catastrophic engine failure. The boost creep effect gets exacerbated with catless test pipes.
Divorced Dump Tubes
On divorced downpipes, the smaller tube that covers the wastegate outlet is called the wastegate “dump tube.” On some downpipes, the dump tube is merged into the larger tube partway down the downpipe. However, there is also the option on some for the dump tube to be left open and not connected. This vastly increases the sound of the downpipe to epic proportions, but attracts a lot of attention. This option should really be reserved for track cars, as it is absolutely thunderous.
Evo X Downpipe Upgrade Benefits
Most people looking at an Evo X downpipe upgrade are concerned with horsepower and torque gains, but there are several other benefits that come with it.
- +10-15 horsepower/torque
- Improved turbo efficiency
- Quicker turbo spool
- Louder and more aggressive exhaust tone
- Reduced backpressure
- Reduced EGT
An upgraded downpipe on the 4B11 will net between 10-15 horsepower and 10-15 lb-ft of torque. The gains would be more if a catalytic converter was being removed, but those are not a factor in these downpipes. Still, there are some noticeable power gains that will be had and the car will definitely feel livelier.
One of the biggest improvements an aftermarket downpipe will give is reduced backpressure, which aids in both turbo efficiency and spool. Your turbo will spool noticeably quicker after an Evo X downpipe upgrade, due to the ability to push exhaust gas through quicker and easier. This also reduces exhaust gas temperature (EGT), and overall makes the engine and turbo work more efficiently.
In addition, you will also see an increase in sound from an 4B11 downpipe upgrade. The tone will be deeper, more aggressive, and much louder. This is even more apparent when paired with an aftermarket test pipe and cat back. Especially if there is an open dump tube.
Tuning Considerations
Tuning is not necessary after upgrading to a new downpipe on the Evo X, but it is always recommended for the biggest gains. Tuners can take advantage of the reduced backpressure and greater flow by increasing boost. This gives more power throughout the powerband and makes the car stronger and quicker everywhere.
Best Evo X Downpipes
Now that we understand the benefits and reasoning for the 4B11 downpipe upgrade, let’s get into the recommendations. Instead of a comprehensive list, we will instead look at the top-four Evo X downpipe upgrades based on price, quality, reputation, and performance.
1) AMS Performance Evo X Widemouth DP
Price: $529.95
Design: Widemouth
First up on our list is the AMS Evo X Widemouth Downpipe. It is a widemouth design and one of the most sought out and recommended downpipes on the market. The Evo X AMS downpipe is a fantastic combination of price and performance, with fitment and quality being top-notch. AMS makes them entirely from 304 stainless steel and they are full 3” throughout, allowing for maximum gains.
The Lancer Evolution X will see power increases of 10-15 horsepower and torque after installing the AMS downpipe. You should also notice much improved turbo spool, too. It is one of the better flowing downpipes on the market and has been used on some really big horsepower builds. The AMS Evo X downpipe features direct OEM fitment to the turbo and test pipe, making it a great first mod for many enthusiasts.
2) ETS Evo X Divorced Downpipe
Price: $695.00 – $795.00
Design: Divorced
The next entry on our list is the Extreme Turbo Systems (ETS) Divorced Dump Downpipe. It is a divorced style downpipe and the dump tube has two options – recirculated or open. The recirculated option merges the dump tube back into the larger tube, whereas the open version lets it vent to the atmosphere. The open option is much, much louder, and is really meant for dedicated track or show cars.
The Lancer Evolution X will see power increases of 10-15 horsepower and torque with the ETS divorced downpipe. Both versions of the dump tube offer the same power, with the difference being sound. As usual for ETS, their downpipe has been used on some pretty iconic builds, including some 7 second Evo Xs.
Like the AMS Performance DP, the ETS tube also offers direct OEM fitment to the test pipe and turbo. Fitment and quality are exceptional on the ETS downpipe, and users can’t go wrong installing it on their 4B11.
3) MAPerformance Evo X O2 Eliminator Downpipe
Price: $793.49 – $811.89
Design: Divorced
The MAPerformance Evo X Eliminator Downpipe is one of the most tried and tested downpipes on the market. It is known for being a fantastically engineered and fabricated downpipe, and is capable of 10-15 horsepower and torque gains. The MAPerformance Eliminator downpipe is also available with ceramic coating for a very reasonable price.
The MAPerformance Eliminator is a solid Evo X DP upgrade choice. It is divorced style with a recirculated dump tube. The dump tube helps to reduce boost creep, and it has the option of a CNC 3D contoured flange for those with larger turbos. The O2 Eliminator name comes from the integrated O2 sensor housing, which not all downpipes have.
4) Tomei Evo X Widemouth Downpipe
Price: $531.00
Design: Widemouth
The final entry on our list is the Tomei Evo X 3” Widemouth Downpipe. It is a widemouth style downpipe, and like the AMS is full 3” throughout. It is a great option for the 4B11, and Tomei is widely known for their excellent quality and fitment.
Installing this downpipe on the Evo X will net 10-15 horsepower and torque, and should significantly reduce spool time and backpressure. The Tomei is known for being one of the louder options on the market. It also comes with exhaust heat wrap included which aids with flow.
A Downpipe Upgrade For Your Evo X Is Great Value For Money
As far as modding goes, an Evo X downpipe upgrade is one of the best choices. It keeps the car emissions compliant while still unlocking some horsepower and torque. The volume increase is also nice and adds a distinct and aggressive tone to the exhaust.
Not only are the power gains great, but the reduced back pressure and EGTs are also great benefits. Reduced back pressure means the turbo will spool faster and work more efficiently, greatly increasing the power band.
This guide looked at four top options for Lancer Evo X downpipe upgrades, including both divorced and widemouth styles. The ETS and MAPerformance are both great divorced style options at a similar price. Both are manufactured in the USA, with the ETS having the option for the open dump tube. Likewise, both the AMS Performance and Tomei downpipes are great widemouth options. Quality and price wise they are nearly identical, with AMS getting the nod due to its reputation within the community.
What’s your experience with Lancer Evo X downpipe upgrades? Are you considering one?
Leave a comment and let us know!
Evo X Downpipe FAQ
An Evo X downpipe will add 10-15 horsepower and 10-15 lb-ft of torque. The real gains in upgrading the Evo X exhaust come from the test pipes.
The best Evo X downpipe is the AMS Widemouth downpipe. It produces solid horsepower and torque gains.
It depends. Evo X downpipes do not offer a ton of horsepower, but sound good and do increase performance a little bit. For most people, a downpipe is a solid upgrade.
