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 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.

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.

Stage 1 mods: Drilled & smoothed airbox, Panel air filters, Remaps/piggy back ECU, Intake headers, Sports exhaust manifold, Fast road camshaft.

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

Stage 3 mods: 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.

It will usually give around 30% more power on turbocharged vehicles and you can expect to see around 15% on NASP 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 headers 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

NASP 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 may end up will reduce the flow rate. Stick to 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 will help avoid this restriction.

Weak spots Issues & problem areas on the 6A12

The 6A12 engines are generally reliable and solid as long as they are regularly serviced and maintained.

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.

For more information 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.

Please help us improve these tips by sending us your feedback in the comments box below.

We love to hear what our visitors have got up to and which tuning parts work best for them on each model of car. Comments are used to improve the accuracy of these 6A12 articles which are continually updated.

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