Mitsubishi 6A13 Tuning

"All you need to know about tuning the Mitsubishi 6A13 engine!"

This pages aim is review 6A13 tuning and summarise the best modifications. Mitsubishi 6A13 are good project engines and with a few sensible motorsport upgrades like a remap, turbo kits and camshafts you will noticeably maximize your driving opportunities.

History, Power & Specs of the 6A13 Engine


  •  120–129 kW (163–175 PS; 161–173 hp) at 5750 rpm
  •  223–230 Nm (164–170 lbft) at 4500 rpm

6A13 Twin Turbo DOHC

  • 350 kW (476 PS; 469 hp) at 5500 rpm
  • 850 Nm (627 lbft) at 4000 rpm

1996–2003 Mitsubishi Galant/Legnum VR-4 — EC5A/EC5W

Tuning the Mitsubishi 6A13 and best 6A13 performance parts.

Best 6A13 parts

When talking about the optimum modifications for your 6A13 engine, we are going to focus on the parts that give the best power gain for you money.

Altering your 6A13 camshaft will make a dramatic difference to the engine engines power. Choosing a higher performance camshaft profile raises the engines power accordingly.

Fast road camshafts normally boost the torque over the rpm band, you may lose a little low down torque but the high end rpm power will be higher.

Motorsport camshafts, boost the high end rpm power band but as a result the car will not idle smoothly and low end power nearly always suffers.

A Motorsport cam is not great in heavy traffic.

You should ideally optimize your power band to your typical driving style so for a daily driver stick with a fast road 6A13 cam

Some 6A13 engines respond better to less aggressive camshaft durations than others.

The ECU mapping and injectors and fuel pump also will make differences on the power gains you'll get.

Extending exhaust or intake durations can alter the power 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.

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

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

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

The 6A13 engines respond well to upgrades and thanks to their popularity there are increasing numbers of modifications and performance parts about.

A remap will help to establish the full potential of all the parts you've done to your 6A13.

(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 NASP engines, but your mileage usually rely on the parts you've done and the condition of your engine.

It is the main goal to any car tuning job to feed more fuel and air into your 6A13

Headers carry the air during the suck phase from the filter and allow it to be drawn into the engine cylinders.

The shape and rate of flow of the Intake can make a big effect on to fuel atomisation on the 6A13.

We often see headers are begging for aftermarket parts, although some makers provide fairly well optimized headers.

Increasing the 6A13 valve size, getting port matching and head flowing will also lift torque, and importantly will raise potential for increasing the torque increase on other upgrades.

6A13 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 6A13

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

If your motor is turbocharged, tuning mods are relatively easy and most turbo engines already contain many forged and stronger components.

However you'll find engines have weakspots.Discover these limits and upgrade to more solid crank and pistons to survive the power.

There are many people spending a a stack of money on turbo upgrades on the 6A13 only to watch the car go up in smoke when it's been finished.

Larger upgraded turbos commonly suffer a bottom end lag, and little turbos spool up much more quickly but won't have the top end engines power gains.

In the last 10 years the world of turbos is always evolving and we are seeing variable vane turbos, where the vane profile is altered according to speed to lower lag and increase top end bhp.

Twin scroll turbos divert the exhaust gases into two channels and feed these at differently angled vanes in the turbocharger. They also improve the scavenging effect of the engine.

It is common that there is a limitation in the air flow sensor AFM/MAF on the 6A13 when loads more air is being pulled into the engine.

We note 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor limited performance at a much lower level.

Adding a supercharger or additional turbo will make large power gains, although harder to configure. We have this guide to twinchargers if you want to read more.


You will need to ensure that the engine is not starved of fuel so will need to look at the fuelling when you start extending past 20% of a bhp and torque increase.It is important to over specify your flow rate on the injectors.

The rule of thumb is to add 20% when fitting an injector, this allows for injector deterioration and affords some spare capacity should the engine need 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.

6A13 Performance Exhausts

You only need to to increase your exhaust if the current exhaust is actually causing a restriction.

On most factory exhausts you'll see your flow rate is fine 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 equal out the flow of air through the engine.

But if your exhaust pipe is too large, ie: over 2.5 inches bore, you will lose a lot of the exhaust flow rate and end up losing power and torque.

Typically exhaust restrictions can be traced to the catalysts installed, so adding a faster 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 6A13

The 6A13 engines are generally reliable and solid 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 6A13, 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 6A13 engine please join us in our friendly forum where you can discuss 6A13 tuning options in more detail with our 6A13 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.

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 modifications work best for them on each model of car. Comments are used to improve the accuracy of these 6A13 articles which are continually updated.

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