Mitsubishi 6B31 Tuning

"All you need to know about performance parts and tuning the Mitsubishi 6B3 engine!"

The 6B31 Mitsubishi engine is a V6 engine used in various Mitsubishi vehicles. It's a part of the MIVEC (Mitsubishi Innovative Valve timing Electronic Control) engine family. This engine is known for its smooth performance and reliability.

The 6B31 engine comes in different displacements depending on the specific model and year, but it's typically around 3.0 liters, which is a decent size for a V6 engine.

The 6B31 engine has been used in various Mitsubishi vehicles, including the Mitsubishi Outlander and Mitsubishi Lancer. It's commonly found in mid-sized SUVs and sedans.

Many owners of vehicles with the 6B31 engine report good long-term reliability. Proper maintenance and care can help ensure it continues to perform well.

In summary, the 6B31 Mitsubishi engine is a V6 engine known for its use of MIVEC technology, which enhances both power and fuel efficiency.

The Mitsubishi 6B3 make awesome project engines and with the best modifications like remaps, turbo kits and camshafts you will noticeably maximize your driving enjoyment.

Because so many readers have emailed and posted questions about the 6B31 and recommendations on how to modify one, we've created this guide to go over what we feel are the primary areas which make for improvement and tuning success on this great car.

Here we look at 6B3 tuning and highlight the premier modifications for your car.

History, Power & Specs of the 6B3 Engine

Naturally aspirated 60° V6 3.0 L (2,998 cc)


  • 220 PS (162 kW; 217 hp) at 6250 rpm, 276 Nm (204lbft) at 4000 rpm
  • 230 PS (169 kW; 227 hp 276 Nm (204lbft) at 4000 rpm, 291 Nm (215lbft) from 2010

Tuning the Mitsubishi 6B3 and best 6B3 performance parts.

Best 6B3 mods

The ultimate 6B3 tuning mods on an engine are as we have found the ones that give the biggest return for your cash.

We won't be swayed by popular 6B3 tuning mods, they need to be cost effective.

MIVEC Technology: Mitsubishi's MIVEC technology is incorporated into this engine. It allows for variable valve timing and lift, which improves efficiency and performance. The engine can adjust the timing of the intake and exhaust valves to optimize power and fuel economy.

MIVEC, which stands for Mitsubishi Innovative Valve timing Electronic Control system, represents a sophisticated variable valve timing (VVT) engine technology created by Mitsubishi Motors.

The process of tuning MIVEC has the potential to enhance your engine's performance by boosting both power and torque across a wide range of engine speeds.

Nevertheless, it's crucial to recognize that MIVEC tuning is a complex procedure that demands a profound comprehension of the engine's inner workings and the tuning process itself.

It is strongly advisable to seek the guidance of a skilled mechanic or tuner with expertise in MIVEC engines before embarking on any tuning endeavors. I trust this information proves valuable to you!

Different 6B3 engines respond better to less aggressive cam durations so view each engine as unique.

The map and injectors and fuel pump also have a large bearing on the bhp gains you'll get.

A longer valve duration can alter the bhp band and on most engines the exhaust and intake durations do not need to match, although most cams and tuners use matched pairs there are some advantages to extending the intake or exhaust durations.

Please watch our video which covers the 5 principles of tuning your car. Be sure to keep up with our latest YouTube content and subscribe.

Best mods for your 6B31

  1. Engine Tunes - 6B31 engine tuning/remapping provides the most advantage compared to cost, aftermarket ECU upgrades, and piggyback ECUs are all alternatives.
  2. Fast road Camshafts are generally the biggest mechanical mod upgrade, but they must be setup by someone who knows what they are doing and they are not always easy to source but you might find a local firm to regrind a stock camshaft.
  3. Intake Upgrades and Sports Exhausts - Note that on their own these mods won't ADD POWER in most cases, but they can help enhance power after other mods by removing the restriction.
  4. Turbo upgrades - Adding a turbocharger is the most efficient approach to increase air supply, allowing you to burn more fuel and make more power. It is one of the most costly upgrades it offers big gains.
  5. Flowing and porting the engine head - for larger gains, you will get better flow and make a more efficient engine if you do this to support your other mods.

Engine Tunes: When it comes to enhancing the performance of a 6B31 engine, engine tuning or remapping stands out as a cost-effective method.

This process involves adjusting the engine's computer, known as the Engine Control Unit (ECU), to optimize various parameters like air-fuel mixture and ignition timing.

Aftermarket ECU upgrades and piggyback ECUs are alternative approaches. They allow you to fine-tune your engine for better power and efficiency.

These modifications often provide the most advantage for the money spent.

Intake Upgrades and Sports Exhausts: Upgrading the intake system and installing sports exhausts are popular modifications, but it's important to note that, on their own, they might not add a significant amount of power.

What they do is reduce restrictions in the air intake and exhaust systems. This means they won't result in massive power gains by themselves, but they can significantly enhance the effects of other modifications.

When combined with engine tuning or turbocharging, these upgrades allow the engine to breathe more freely, improving overall performance.

Turbo Upgrades: If you're looking for substantial power gains, adding a turbocharger is an efficient approach.

Turbochargers increase the amount of air supplied to the engine, allowing it to burn more fuel and generate more power.

However, it's important to note that turbocharging is one of the more costly upgrades. Still, it offers significant gains in horsepower and torque.

The increased air supply from the turbocharger can transform your 6B31 engine into a more potent machine.

Flowing and Porting the Engine Head: To achieve even larger gains in performance, you can consider flowing and porting the engine head.

This involves modifying the shape and size of the passages that air and exhaust gases flow through within the cylinder head.

By optimizing the airflow, you can make the engine more efficient and increase its power output. This modification works best when combined with other performance upgrades, as it allows the engine to make better use of the increased airflow provided by intakes, exhausts, and turbochargers.

6B31 Tuning Stages

Typical stage 1 mods often include:
Fast road camshaft, Panel air filters, drilled & smoothed airbox, Sports exhaust header/manifold, Intake manifolds, Remaps/piggy back ECU.

Typical stage 2 mods often include:
Sports catalyst & performance exhaust, induction kit, high flow fuel injectors, fuel pump upgrades, Fast road cam, Ported and polished head.

Typical stage 3 mods often include:
Competition cam, Adding or Upgrading forced induction (turbo/supercharger), Engine balancing & blueprinting, Internal engine upgrades (head flowing porting/bigger valves), Crank and Piston upgrades to alter compression, Twin charging conversions.

The 6B3 engines make great tuning projects and thanks to their popularity there are increasing numbers of mods and performance parts out there.

ECU flashing will help unlock the full potential of all the modifications you've done to your 6B3.

(In some cases, as the factory ECU is locked flashing is not an option, so an aftermarket ECU is the route to take, and many of these will outperform factory ECU's but make sure it has knock protection and that you get it setup properly.)

It will usually give you around 30% more power on turbocharged vehicles and you can expect to see around 15% on NA (naturally aspirated) engines, but figures achieved usually differs on the modifications you've carried out and the condition of your engine.

Pulling air into each cylinder is the whole point to any engine upgrade project.

Intake transmit the air from the filter and allow it to be drawn into the engine cylinders.

Shape and flow rate of the Air Intake manifolds can make a noticeable difference to fuel delivery on the 6B3.

It's not uncommon that intake are improved through performance upgrades, although some car makers provide reasonably well designed intake.

Larger 6B3 valves, getting port work and head flowing will also raise bhp and torque, and more importantly will allow you to get increasing the bhp and torque increase on other parts.

6B3 Turbo upgrades

NA (naturally aspirated) engines need quite a lot of work when you add a turbo, so we have a separate guide to help you take into account the pros and cons of going this route on your 6B3

The more air you can get into an engine, the more fuel it can burn and uprating the induction with a turbocharger upgrade makes massive power gains.

When an engine is turbocharged, tuning parts are going to net you a larger power gain and turbocharged engines use better components.

However engines have limits.Discover these limitations and install better quality components to handle the power.

It's not unheard of car owners spending a fortune on turbo charger upgrades on the 6B3 only to see the motor throw a rod when it's been finished.

Large turbochargers will usually experience no power at low rpm, and smaller turbochargers spool up much more quickly but do not have the peak end bhp gains.

Over the last 20 years the choice of turbos is always improving and we now see variable vane turbos, where the vane profile is altered according to speed to lower lag and increase top end torque.

Twin scroll turbos divert the exhaust flow into 2 channels and feed these at differently designed vanes in the turbo charger. They also increase the scavenging effect of the engine.

It is common that there's a limitation in the air flow sensor MAF/MAP on the 6B3 when loads more air is being drawn into the engine.

You'll see that 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor was restricting power at a much lower level.

Adding a supercharger or additional turbo will make large bhp and torque gains, although more challenging to install. We have this guide to twinchargers if you want to read more.


Don't forget to ramp up the fuel delivery when you are increasing the performance - it makes the car more thirsty. We would recommend you to be generous with your injectors flow rate.

The accepted safe increase is to add 20% when fitting an injector, this accounts for injector deterioration and gives a little spare capacity should the engine require more fuel.

We think this one is common sense, but you'll need to match your fuel injector to the type of fuel your car uses as well.

6B3 Performance Exhausts

You only need to replace your exhaust if the existing exhaust is creating a flow problem.

On most factory exhausts you'll see your flow rate is still ok even on modest power gains, but when you start pushing up the power levels you will need to get a better flowing exhaust.

Sports exhausts generally help improve air flow out of the engine but do not go too big or you might just stuff your flow rate and make things worse. So generally speaking, keep to a size of 1.5 to 2.5 inches for best results.

Common exhaust restrictions come around the emissions filters installed, so adding a higher flowing race alternative such as a sports catalyst pretty much removes this restriction, thanks to it's larger size and surface area, and will effectively raise the performance to levels you would expect without having a catalyst installed, but keeps the car road legal.

Weak spots, Issues & problem areas on the 6B3

The 6B3 engines are generally reliable and solid units, as long as you follow the manufacturers service schedules, and use a good quality oil to ensure longevity. Few problems should happen as long as they are regularly serviced and maintained.

Carbon build up in the head, particularly around the valves which will sap power or create flat spots, this is a larger issue on direct injection engines but should be looked out for on all engines. We have tips on removing carbon build up.

Some of our members have had issues with flat spots or glitches after applying mods and upgrades or tuning, this is not usually related to this engines design, so instead see our article on diagnosing flat spots and problems after tuning which should help you get the bottom of this issue.

Regular oil changes are vital on the 6B3, especially when tuned and will help extend the life and reliability of the engine.

If you would like to know more, or just get some friendly advice on Tuning your 6B3 engine please join us in our car forums where you can discuss 6B3 tuning options in more detail with our 6B3 owners. It would also be worth reading our unbiased Mitsubishi tuning articles to get insights into each modification and how effective they will be for your car.

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