Mitsubishi 4G63 Tuning

"All you need to know about tuning the Mitsubishi 4G63 engine!"

The 4G63 is one of our most talked about engines, and for good reason.

When Rallyart took it and tuned it we saw a phenomenally powerful 2.0 4 cylinder engine. They are solid and reliable and give good returns for pretty much every mod you throw at it.

Our aim here is to detail the best approach to 4G63 tuning and highlight the premier modifications.

Mitsubishi 4G63 are good project engines and with the best sports upgrades like ECU maps, turbo improvements and camshafts you will substantially increase your driving enjoyment.

History, Power & Specs of the Engine

4G63 G63B 1,997 cc (2.0 L)

Tuning the Mitsubishi 4G63 and best 4G63 performance parts.

Best 4G63 tuning mods

The greatest 4G63 mods on an engine are obviously the ones that give the best value for money.

We won't be swayed by popular 4G63 mods, they need to be cost effective.

Significant gains on the 4G63 can be made from cam upgrades. Altering the cam profile alters the intake and exhaust durations on the engine and can dramatically change the engines power and power output.

Fast road cams normally boost the performance through the rev range, you may lose a little low end bhp but the higher rpm power will be better.

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

A Race camshaft won't do well if on the daily commute, because the lumpy idle will make the car prone to stall and smooth driving at low rpm becomes impossible. If you are developing a track car this doesn't matter as you are in the high end of your RPM range anyway and that is where you want the power to be.

You should ideally optimize your engines power to your usage of the car so for a car driven daily stick with a mild fast road 4G63 camshaft

Each engine responds better to different camshaft durations so set your engine up on a rolling road.

The engine timing and fuelling also will make differences on the torque gains you'll make.

Altering valve 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. Mapping - 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: Sports exhaust header/manifold, drilled & smoothed airbox, Fast road camshaft, Remaps/piggy back ECU, Intake manifolds, Panel air filters.

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

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

Review your options and then find your parts and set yourself a power target to avoid wasting your time and money.

remap helps fully realize the full potential of all the tuning parts you've fitted to your 4G63.

(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 your results may depend much on the tuning parts you've carried out and the condition of your engine.

It is the aim to any car tuning job to pull more air and fuel into your 4G63

Intake manifolds take the air from the filter and allow it to be drawn into the engine and mixed with fuel.

The shape and flow rate of the Intake manifolds can make a substantial improvement to fuel delivery on the 4G63.

Commonly we find the intake are in desperate need of aftermarket parts, although a few car makers provide reasonably good intake.

Increasing the 4G63 valve size, doing a bit of 3 or 5 angle valve jobs and porting and head flowing will also increase performance, and significantly will give you increasing the performance 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 4G63

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 tuning parts are giving better power gains and turbocharged engines use better components.

However most engines will need better parts at higher power limits

See where you'll find these restrictions and upgrade to more solid crank and pistons to utilize the power.

There are many drivers spending a lot of money on turbo charger upgrades on the 4G63 only to suffer the humiliation of seeing the 4G63 explode just after it's been completed.

Larger turbo chargers tend to suffer low end lag, and little turbo chargers spool up really quickly but won't have the top end power band gains.

In the last 10 years the selection of turbo chargers is always moving on and we now see variable vane turbo chargers, where the vane angle is altered according to speed to lower lag and increase top end power.

Twin scroll turbo chargers divert the exhaust flow into two channels and push 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 MAF/MAP on the 4G63 when a lot more air is being sucked into the engine.

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

Adding a supercharger or additional turbo will make large power gains, although more difficult to setup. We have this feature on twinchargers if you want to read more.

Fuelling

You will need to ensure that the engine is not starved of fuel so should ramp up the fuelling when you start exceeding 20% of a bhp and torque increase.Most tuners we speak with say to be generous with your injectors flow rate.

As a rule of thumb add 20% when fitting an injector, which takes into account injector deterioration and allows you some 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.

All the following flywheel power targets will assume an injector duty cycle of 80% and a base of 58psi of fuel pressure at idle.

4 Cylinder turbocharged engines

  • 58 PSI 340cc/min 200hp
  • 58 PSI 511cc/min 300hp
  • 58 PSI 682cc/min 400hp
  • 58 PSI 1022cc/min 600hp

4 Cylinder NA (naturally aspirated) engines

  • 58 PSI 285cc/min 200hp
  • 58 PSI 426cc/min 300hp

4 Cylinder supercharged engines

  • 58 PSI 312cc/min 200hp
  • 58 PSI 468cc/min 300hp
  • 58 PSI 625cc/min 400hp
  • 58 PSI 937cc/min 600hp

Exhaust

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

On most factory exhausts you should find that the flow rate is good even on modest power gains, but when you start pushing up the power levels you will need to get a better flowing exhaust.

Note that with the widest exhaust you can buy you'll slow the exhaust rate - the best exhausts for power gains are usually between 1.5 to 2.5 inches. It is the shape and material more than the bore size.

Typically exhaust restrictions are in the filters installed, so adding a freer flowing performance catalyst removes the restriction. We note that performance cats perform similarly to decats and have the added benefit of keeping your car street legal, as decats or catalyst removal is illegal in most territories for road going cars.

Weak spots Issues & problem areas on the 4G63

The 4G63 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 4G63, 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 4G63 engine please join us in our friendly forum where you can discuss tuning options in more detail with our 4G63 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 upgrades work best for you on your car. Which helps us keep our guides and tips up to date helping others with their modified car projects. Your feedback and comments are used to keep this page up to date, and help improve the accuracy of these 4G63 tuning guides which get regular updates and revisions.

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