The 7 Best Lancer Evo X Performance Mods

The Evo X is the 10th generation of the Mitsubishi Lancer Evolution. Released in model year 2008 the Evo X was produced for 7 years before being discontinued by Mitsubishi after 2015. Despite its demise, the Evo X and its predecessors remain iconic tuner cars in the performance enthusiast community.

In addition to a new body design, the Evo X also received a new engine, replacing the historic 2.0L inline-4 turbo 4G63. The new 4B11T engine follows the same 2.0L turbo I4 structure but received an aluminum block, a new turbocharger, forged rods, and stronger internals capable of handling more boost.

The 4B11T Evo X produces 287hp and 300lb-ft. of torque in the US market, which is the same horsepower output as the 4G63 and 11lb-ft. torque increase over the 4G63. Despite its mild power increases, the improvements made to the 4B11T engine make it capable of producing more power than its predecessor.

This is a tuner car, so who cares about stock power. How much power can the Evo X handle when modded? We’ll cover this in more detail below, but a few simple bolt-on mods and fueling upgrades can get your Evo X to 350whp pretty easily.

Best Lancer Evo X Performance Upgrades

• Flash tune
• Cold air intake
• Front pipes
• FMIC piping
• Fueling / E85 Fuel
• Blow off valve (only good for 25psi)
• Boost controller

Mods recommended for >350whp

• FMIC upgrade
• Injector upgrades
• Turbo / turbo manifold
• Camshaft upgrade
• Internal and block upgrades

1. Evo X Flash Tune / Custom Tuning

The best bang-for-the-buck mod on an Evo X, and really any turbo engine, is a flash tuner. Flash tunes come with an array of off-the-shelf (OTS) maps that can be turned on and off easily with a simple hand held device that plugs directly into the OBDII port. Tunes adjust fueling, AFRs, boost targets, timing, and other variables to increase power and provide a smoother and more consistent power band.

Additionally, a tune is important for any Evo X looking to add further modifications such as an intake or exhaust upgrades. A tune is able to adjust the factory tune to account for the additional air flow from Evo X intake upgrades, for example. Not only does this give you a healthier engine, it also helps maximize the performance gains achieved from these other performance mods. While an intake might get you 5whp on a stock engine, combine it with a tune and the gains will be closer to 10whp.

A flash tune is an essential modification if you are looking to get to the 300whp+ ballpark. The alternative option is custom tuning which we start to recommend around the 350whp range. Flash tuners, such as the Cobb Accessport will come with pre-built maps that can accommodate most simple bolt-on mods. However, once you start throwing fueling upgrades, turbo upgrades, and other more advanced mods, the benefits of a custom tune become more important not only for power gains but also for reliability.

Evo X Flash Tune Benefits

Benefits of Mitsubishi 4B11T tuning include:

• 30-60whp gains
• Similar torque gains
• Smoother, expanded power band
• Plug-and-play

There are a few different options on the market such as the Cobb Accessport, VR Tuned, EcuTek, etc. We recommend the Cobb Accessport as it tends to be the most popular and is supported by most custom tuning shops.

2. 4B11T Cold Air Intake Upgrade

Most of the power gains from a tune come from turning up boost levels. While the stock intake system on the Evo X is completely capable on lightly modified engines, once you turn up the boost it starts to become restrictive. Running high levels of boost without more air flow puts extra stress on the turbo and decreases reliability and efficiency of the turbo.

Performance intake systems will provide ~50% more air flow than the stock intake system. This takes stress off of the turbocharger and improves its efficiency. Again, as mentioned above the benefit of an intake really only comes into play when boost levels are increased. An intake system on a completely stock engine won’t provide more than a few horsepower.

We usually discuss open vs. closed intake systems but all of the intake systems for the Evo X are open-air systems. However, the names of the intake systems do vary. You will see cold air intake, ram air intake, performance intake, etc. Don’t get caught up in the name, they are all the same.

Some people might have concerns that the open air intakes draw in hotter air. While most have a heat shield anyways, it really doesn’t matter. Intake air is heated up by the turbo anyways and flows through the intercooler before entering the engine, so the slightly higher IATs don’t really matter.

4B11T Cold Air Intake Benefits

Some benefits of Evo X air intake upgrades are:

• 5-12whp gains and similar torque gains
• 50%+ improvement to air flow
• Improved turbo efficiency and reliability
• Awesome intake sound gains

Best Evo X Intake Systems

• AMS Performance
• ETS Air Intake System
• K&N Cold Air Intake

The benefits from brand to brand don’t really differ too much. All of them use similar designs and high quality larger filters for increased airflow. The only system we don’t really like is the AEM Intake since it uses a fully enclosed box. Since it is fully enclosed it is more restricted than the open systems above and therefore will flow less air. It will provide slightly lower IATs but as we mentioned earlier this doesn’t matter. More air flow is more beneficial than marginally lower IATs.

3. Evo X Downpipe & Front Pipe Upgrades

Most turbocharged engines have the catalytic converter sitting directly in the downpipe. The downpipe bolts directly to the turbo and therefore is the initial exhaust component in a turbo car. However, the 4B11T engine actually doesn’t have a catalytic converter inside the downpipe.

Instead, the catalytic converter sits in the front pipe or the test pipe. This front pipe bolts directly to the downpipe. Catalytic converters are naturally restrictive and create increased backpressure in the exhaust system which has a negative effect on the turbocharger. Backpressure decreases the turbos ability to spool quickly and puts more stress on it. Therefore, upgrading the front pipe is recommended to reduce backpressure which also lowers EGTs and takes stress off the turbo. Running high levels of boost on the stock exhaust system puts a beating on the stock turbo.

The second component of the exhaust system is the cat-back portion. While upgrading the cat-back portion will help reduce some additional backpressure, the most important exhaust component to upgrade is the front pipe. We really only recommend cat-back upgrades for the people who want a louder exhaust note since the power gains don’t justify the cost.

Front Pipe Upgrade Benefits

Downpipe and front pipe upgrades for the Evo X 4B11T include:

• 10-15whp gains and similar torque gains
• Lower exhaust gas temps
• Less exhaust backpressure
• Faster turbo spool
• Better turbo reliability

Catless vs. Catted Front Pipes

When upgrading the front pipe you can either opt for a catless pipe, also commonly called a test pipe, or a high-flow catted pipe. Catless pipes offer the best power gains since they reduce backpressure the most. However, they are illegal and will cause you to fail emissions. High-flow catted pipes will pass emissions in most states but will provide slightly less power gains since they still have a semi-restrictive catalytic converter in them.

4. Evo X FMIC / Piping Upgrades

The front mount intercooler from the factory is actually quite good. It is large and has adequate airflow even for tuned and modified 4B11T engines. While the intercooler itself is very good, the factory piping is not. The stock piping uses a lot of very long silicone hoses. These hoses experience a lot of expansion under heavy boost which creates inconsistent boost spikes or variations in the boost curve. Replacing these silicone hoses with a hard pipe kit is common to provide better boost control, consistent air flow, and improved throttle response.

You have two options here: just replace the piping or upgrade the full FMIC. While we prefer just to upgrade the FMIC while you’re doing the piping, it really isn’t necessary until you are pushing over 350whp. However, upgrading it before then could be beneficial if you are tuned and track your car or use it for aggressive street driving. While the factory intercooler is good an upgraded one will still provide lower IATs and minimize turbo heat soak.

It’s up to you on whether you upgrade the piping or the full FMIC. Most forum folks don’t recommend spending the money on the full intercooler unless you are running into a lot of heat soak or are upgrading your turbocharger.

Evo X FMIC Piping Benefits

• Better boost control
• Increased air flow
• Quicker throttle response
• ~10whp with full FMIC upgrade

An FMIC (and upgraded piping) aren’t really power producing mods. They are more so reliability and power loss prevention mods. Upgraded piping will give you more consistent boost which will provide smoother power delivery. A full FMIC will prevent heat soak which can cause horsepower losses in the 20whp range during aggressive driving or tracking. So both of the mods are more about preventing power loss from heat soak and providing more consistent power delivery.

So while an FMIC does provide some power gains they are rather marginal compared to the other benefits received.

Best 4B11T Intercoolers & Piping

• Cobb Tuning
• ETS
• STM
• AMS
• MAPerformance
• Mishimoto

5. 4B11T Fueling Upgrades & E85 Fueling

E85, also known as flex fuel, is pretty much required to reach 350whp without turbo or cam upgrades. Running all of the mods on this list without E85 will probably put you in the 320whp range. Meaning E85 alone will provide power gains around 30whp, and potentially even up to 50whp.

E85 has a very high octane rating of 108. Additionally, it burns a lot colder than pump gas which allows for more advanced ignition timing and more boost.

However, E85 fuel also burns more quickly and has a lower energy content, which means you need more of it compared to traditional gas. E85 will burn about 25-30% more fuel. This means that your fuel pump and injectors must be able to flow 30%+ more fuel.

On the stock Evo X, the fuel pump and injectors can only handle small blends around the E30 mark, which is probably good for about 10whp. If you want to get more aggressive and run 100% E85 you will need an upgraded fuel pump, and at least 750cc injectors but preferably 900cc+ injectors. And you’ll need some upgraded feed lines. All of the things you need can be bought in a simple E85 flex fuel kit.

Evo X E85 Benefits

• 10-50whp gains and similar torque gains
• Lower engine temps
• More aggressive ignition timing
• Reduced chances of engine knock and pre-detonation
• Higher boost levels

6. Evo X Blow Off Valve

There is some debate on the internet over whether the Evo X blow off valves are all metal or if some are plastic. All US made Evo X’s had metal BOV’s. However, some international MR automatic transmission models came with a plastic blow off valve. Regardless of which you have, replacing the blow off valve is recommended.

The plastic BOV is known to start leaking boost around the 17-18psi mark. The metal BOV leaks significantly above 25psi. Considering the stock turbo is generally safe to run up to about 28psi, we recommend an upgraded blow off valve for anyone planning on running aggressive tunes or boost levels.

A BOV won’t give you any power gains per se, but it will prevent boost from bleeding off which helps hold power at under high boost. Additionally it helps improve turbo response.

You’ll need a custom tune to run E85 and the below boost control upgrades are highly recommended to prevent the turbo from over spinning.

Upgraded Blow Off Valve Benefits

• Prevents boost leak
• More consistent boost levels
• Improved throttle/turbo response
• Ability to run boost above 25psi
• Cool sounds

Best Evo X Blow Off Valve

A number of the best Evo X BOV upgrades are:

• HKS
• Turbosmart
• TiAL
• Greddy
• Forge Motorsport
• TurboXS

7. 4B11T Boost Control Upgrades

There are two different mods we’ll discuss for improved boost control. First is an upgraded boost control solenoid, or an electronic aftermarket controller. Second is a wastegate actuator upgrade.

While none of this upgrades add power they will help hold boost and provide a flatter boost curve. Overall, while not power adding they are important for maintaining power and creating smooth performance through the reduction of boost fluctuations.

Boost Control Solenoid

Similar to the Subaru WRX, the Lancer Evo uses a 2-port electronic boost control solenoid that diverts boost to the wastegate. 2-port solenoids are known to be inaccurate and cause a lot of boost fluctuations. Therefore, option A is to replace the factory 2-port with an aftermarket 3-port boost control solenoid. A 3-port solenoid will help hold boost better, provide more accurate readings for more consistent boost, and reduce stress on the turbo.

The second option to go with a more advanced boost controller, such as the GReddy Profec B Spec 2. An electronic boost controller like this provides more advanced boost customization and for boost to be altered and tweaked through a controller installed inside the car. While these systems are more advanced and provide more customization they are also a bit trickier to install and setup properly.

Unless you need more advanced boost control, we recommend sticking with a 3-port solenoid from either Cobb or Grimmspeed.

Wastegate Actuator Upgrade

The stock actuator on the wastegate wears down over time and eventually starts leaking boost above the 15psi levels above 6,000rpms. Therefore, we recommend upgrading the actuator to a 1.5 BAR actuator in combination with the 3-port EBCS. An upgraded actuator will help provide more consistent boost levels, reduce fluctuations, and help keep the boost curve as flat as possible in the upper rev ranges.

How Much Power Can the Evo X 4B11T Make?

With E85 fueling and a more aggressive tune, the above mods can get you to approximately 350whp. The stock block is the weak point on the 4B11T engine. Most tuners recommend keeping torque below the 400wtq mark unless you have a reinforced block. Torque is the killer of the 4B11T, horsepower levels can reach 450whp+ with decent reliability so long as torque is properly tuned and kept under 400wtq and more ideally within the 360-380wtq range.

Running full E85 and full bolt-ons with an aggressive tune can get you very close to the 400whp mark. However, pushing 400whp+ consistently and reliably is going to require an upgraded turbo and some additional modifications.

Evo X Performance Mods for 350+whp

Sure the stock turbo can surpass 350whp. However, above these levels the turbo is getting pretty close to fully maxed out. Therefore if you want to run a consistent and reliable 400+ then you should consider upgrading your turbo along with the manifold.

Additionally, above 350whp an upgraded FMIC is recommended. The stock FMIC with upgraded piping is completely fine up until this point but eventually you will need a larger intercooler with better flow and more cooling capacity.

Full E85 or high concentrations of E85 will be needed as well. If you weren’t already running E85 first you will need to upgrade you fuel pump and injectors to handle more than small mixes of E85. E85 provides power gains in the 20-40whp range depending on the amount used.

Once you drop an upgraded turbo on the car, and upgraded camshaft is recommended as well. The camshaft will give about 20whp gains.

And lastly, at these levels you are probably going to want to push past 400wtq, which means you should consider reinforcing the block. Internal upgrades usually aren’t needed until you break well into the 500’s for wheel horsepower.

Evo X Stock Turbo & Stock Block Max PSI

Too much boost is also a killer of internals and the block. 28psi is the recommended absolute max boost for the stock turbo on the stock block. Anything above that increases the likelihood of blowing the block and the pistons. If you want to play it safe, keep boost levels under 28psi. Just keep in mind anything above 25psi and you will need an upgraded blow off valve to prevent bleeding boost.

Ideally running any boost levels over 20psi you should have a proper custom tune. Bad tuning and high boost is an easy way to kill your 4B11T block and pistons. And again 28psi+ on the stock turbo is absolutely pushing it. Which is why we recommend an upgraded turbo for anyone that wants to run reliably and consistently in the upper 300’s, or 400+.

What mods do you have on your Evo X? How has your experience been tuning the 4B11T?