Mitsubishi 6A12 Tuning

"All you need to know about tuning the Mitsubishi 6A12 engine!"

TorqueCars will review 6A12 tuning and point out the premier mods that work. Mitsubishi 6A12 have loads of potential and with carefully chosen uprated parts like remaps, turbo improvements and camshafts you will noticeably improve your driving pleasure.

This little V6 engine was silky smooth, very light (for a V6) and put down quite a bit of power, but I guess you are here to see what improvements can be made and thankfully there are many.

We examine 6A12 tuning and outline the greatest mods that work. Mitsubishi 6A12 are popular blocks and with a few sensible modifications like remapping, turbo upgrades and camshafts you will improve your driving experience.

History, Power & Specs of the Engine

  • MIVEC 197 hp at 7500 rpm
  • DOHC 143–148 hp at 6000–6750
  • DOHC & sports ECU 170–177 hp at 7000 rpm
  • DOHC Twin Turbo 237 hp at 6000 rpm

Engine swaps from the DOHC versions to the Mivec and Twin turbo are quite popular, as it uses the same engine block.

  • 1992-1996 Mitsubishi Galant/Eterna/Emeraude
  • 1992-1994 Mitsubishi Diamante
  • 1994-2000 Mitsubishi FTO
  • 1999-2010 Proton Perdana

There was also a 6A13 engine fitted to the Galant, a 2.4 SOHC version and a Twin Turbo DOHC version as found in the VR4

Tuning the Mitsubishi 6A12 and best 6A12 performance parts.

Best 6A12 upgrades

Just because particular upgrades are appear in lots of 6A12 projects it doesn't mean its worth having, so we'll optimum upgrades that will give your 6A12 the best power gain for you money.

Altering your 6A12 cam will make a dramatic difference to the engine torque. Choosing a higher performance cam profile raises the torque accordingly.

Fast road camshafts tend to raise the power throughout the rpm band, you may sacrifice a little low down power but higher rpm power will be higher.

Race camshafts, raise the higher rpm power band but as a result the car will not idle smoothly and low end power nearly always suffers.

A Race cam is not great driving around busy urban areas. This is because a competition cam causes a very lumpy idle, and makes the car more prone to stall or jerk along in stop start traffic, sadly though many ignore this and end up ruining a perfectly good car and having to revert back to a fast road, or OEM cam profile.

You should ideally optimize your engines power to your usage of the car so for a road car stick with a mild fast road 6A12 cam

Each engine responds better to mild cam durations so view each engine as unique.

The engine timing and fuel pump and injectors also have an effect on the torque gains you'll get.

Extending exhaust or intake durations can alter the torque 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.

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Best Engine Mods for your car

  1. Engine Tunes - engine tuning/remapping provides the most advantage in terms of cost savings,  aftermarket ECUs, and piggyback ECUs are all alternatives.
  2. Fast road cams are one of the most significant mechanical changes, but they must be installed by someone who knows what they're doing and they are not always easy to source but you might find a local firm to regrind a stock camshaft.
  3. Intake and Exhaust - Note that on their own these mods will NOT ADD POWER in most cases, but they can help enhance power after other mods by removing the restriction.
  4. Upgrades to turbochargers and superchargers - forced induction 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 but provides the best gains.
  5. Head work - The goals of porting and flowing the head are to get air flowing into the engine while removing flow restrictions and turbulence.

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

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

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

Carefully think through your options and then buy your modifications and set yourself a power target to avoid wasting your time and money.

Mapping helps release the full potential of all the tuning parts you've fitted to your 6A12.

(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 the end result usually rely on the tuning parts you've carried out and the condition of your engine.

Feeding air and fuel into each cylinder is the main goal to any engine tuning task.

Intake manifolds flow the air during the suck phase from the filter and allow it to be sucked into the engine and mixed with fuel.

Design and flow rate of the Plenum can make a noticeable effect on to fuel mixing and power on the 6A12.

Commonly we find the air intake manifolds are improved through a performance upgrade, although a few manufacturers provide reasonably good air intake manifolds.

Increasing the 6A12 valve size, doing some port matching and head flowing will also raise torque, & importantly will permit an improved torque increase on other tuning mods.

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 6A12

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

If the engine has a turbocharger mods are relatively easy and you'll see that turbocharged engines use many forged and stronger components.

However most engines have weakspots

Discover these limitations and upgrade to better quality crank and pistons to utilize the power.

We see many people spending a a stack of money on turbocharger upgrades on the 6A12 only to suffer the humiliation of seeing the car catastrophically fail when it's been completed.

Bigger turbo chargers will usually experience a bottom end lag, and low capacity turbo chargers spool up really quickly but don't have the top end power band gains.

In recent times the world of turbo chargers is always increasing and we commonly find variable vane turbo chargers, allowing the vane profile is altered according to speed to lower lag and increase top end bhp.

Twin scroll turbo chargers divert the exhaust gases into a couple of channels and flow these at differently designed vanes in the turbocharger. They also improve the scavenging effect of the engine.

It is not unusual that there's a limit in the air flow sensor (AFM/MAF/MAP) on the 6A12 when considerably more air is being drawn into the engine.

Going up you'll find 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor limited bhp and torque at a much lower level.

Adding a supercharger or additional turbo will make large bhp and torque gains, although more complex to setup. We have this article covering twinchargers if you want to read more.


Don't omit to boost the fuelling when you are increasing the bhp and torque - it makes the car more thirsty. Most tuners we speak with say to over specify your flow rate on the injectors.

The rule of thumb is to add 20% when buying an injector, which takes into account injector deterioration and affords 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.


You should look to increase your exhaust if your exhaust is creating a flow problem.

On most factory exhausts you'll find the exhaust flow rate is 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 can usually air flow out of the engine but avoid an exhaust that is too large 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 can be located the catalyst installed, so adding a higher flowing sports alternative is the answer. This keeps the car road legal and will flow much better due to it's higher internal surface area and design, so has the added benefit of keeping your car road legal. The alternative decat should be considered an off road only mod, as removing a catalyst is illegal in most territories and regions for road registered cars..

Weak spots Issues & problem areas on the 6A12

The 6A12 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 6A12, especially when tuned and will help extend the life and reliability of the engine.

There are a few issues with ignition coils, and o2 sensors can get problems but these are easily swapped out and we find that TPS is a recurring issue for many owners.

Oil distribution can be an issue at high RPMS, so choosing the right oil grade is vital, and keep the pump serviced.

If you would like to know more, or just get some friendly advice on Tuning your 6A12 engine please join us in our friendly forum where you can discuss tuning options in more detail with our 6A12 owners. It would also be worth reading our unbiased tuning articles to get a full grasp of the benefits and drawbacks of each modification.

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