Mitsubishi 4G6 Tuning

"All you need to know about tuning the Mitsubishi 4G6 engine!"

In this article we review 4G6 tuning and highlight the ultimate upgrades. Mitsubishi 4G6 offer good returns when tuned and with the optimum motorsport parts like remapping, turbo kits and camshafts you will positively maximize your driving experience.

History, Power & Specs of the Engine

4G61 displaces 1,595 cc (1.6 L)

  • 1988–1992 Mitsubishi Mirage / Mitsubishi Colt (MPFI)
  • 1988–1992 Dodge Colt / Plymouth Colt
  • 1988–1992 Eagle Summit
  • 1992–1995 Hyundai Elantra

4G62 1.8 L

  • 1980–1987 Mitsubishi Lancer EX 1800GSR or 1800GT (A175A)
  • 1981–1986 Mitsubishi Delica/L300/Express
  • 1983–1987 Mitsubishi Chariot HR
  • 1983–1989 Mitsubishi Cordia
  • 1983–1989 Mitsubishi Tredia
  • 1984–1988 Mitsubishi Galant/Eterna

4G63/G63B

See separate article for this engine

4G64

  • 1993-1997 Mitsubishi Chariot
  • 1988–2006 Mitsubishi Delica/Van
  • 1997-1999 Mitsubishi Eclipse
  • 1997-1999 Mitsubishi Montero Sport (North American, ES model)
  • 2000-2005 Mitsubishi Eclipse
  • 1994–2003 Mitsubishi Galant
  • 1990–present Mitsubishi L200
  • 1996–1998 Mitsubishi Magna (codenamed 4G64-S4 TE-TF series)
  • 1990–1996 Mitsubishi Mighty Max
  • 1998-2005 Mitsubishi Montero (V11 - 2 door) Latin America
  • 2001 Mitsubishi Airtrek
  • 2003 Mitsubishi Outlander
  • 1987–1990 Mitsubishi Sapporo
  • 1986-2005 Mitsubishi Triton
  • 2005 Mitsubishi Zinger
  • 1998–2004 Mitsubishi Space Wagon

Tuning the Mitsubishi 4G6 and best 4G6 performance parts.

Best 4G6 modifications

The ultimate 4G6 parts on an engine are as we have found the ones that give the best value for money.

We won't be swayed by popular 4G6 parts, they need to be cost effective.

The cam profile plays a big part in the engines power output so cam upgrades make quite a large difference. The intake & exhaust durations will alter depending on the chosen cam profile, so large engines power gains are on offer for cam upgrades.

Fast road cams commonly increase the bhp and torque throughout the rpm range, you could drop a little low down torque but your higher rpm power will be lifted.

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

A Competition camshaft won't do well if driving in heavy traffic.

You should ideally optimize your torque band to your typical driving style so for a road car stick with a shorter duration 4G6 camshaft

Some 4G6 engines respond better to less aggressive camshaft durations than others.

The ecu map and injectors and fuel pump also will say much on the torque gains you'll hit.

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.

Please watch our video which covers the 5 principles of tuning your car. Be sure to subscribe and support our new channel.

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

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

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

Plan your options and then acquire your mods and set yourself a power target to avoid costly mistakes.

ECU flashing helps fully realize the full potential of all the parts you've fitted to your 4G6.

(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 mileage may vary depending on the parts you've done and the condition of your engine.

It is vital to any engine modification job to push air and fuel into each cylinder

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

Structure and flow rate of the Plenum can make a big difference to fuel mixing and power on the 4G6.

Many mass produced engine plenum chambers are needing an upgrade, although some makers provide decently flowing plenum chambers.

Adding a 4G6 larger valve kit, doing a bit of port work and head flowing will also boost power, and as an added benefit will permit raising the power increase on other modifications.

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 4G6

Take the 2.4 4G64 as an example - this will not cope with much extra boost, so the absolute limit is around 10psi and I'd say go lower than this for safety. This is thanks to the high compression ratio.

As an example a single turbo giving 7psi of boost will push you to around 216hp to 247hp, at 5 psi you get to around 197. A lot depends on the engine condition and how well the exhaust flows.

There is a factory turbo kit doing the rounds which actually works pretty well and irons out most of the guesswork and setting up you will encounter on a supercharging project.

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

When your motor is turbo charged parts are more reliable and turbo charged engines already contain better components.

There are practical limits for every engine, with some being extremely strong and some only able to handle stock power

Discover these limits and fit more solid crank and pistons to survive the power.

We've seen people spending a lots of money on turbocharger upgrades on the 4G6 only to see the motor literally blow up just after it's first rolling road session.

Larger capacity turbo units commonly suffer no power at low rpm, and small turbo units spool up quickly but don't have the top end torque gains.

Thanks to progress the market of turbo chargers is always evolving and we now see variable vane turbo chargers, permitting the vane angle is altered according to speed to lower lag and increase top end torque.

Twin scroll turbo chargers divert the exhaust gases into a couple of channels and push these at differently angled vanes in the turbo charger. They also boost 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 4G6 when a lot more air is being drawn into the engine.

We note 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 torque gains, although more challenging to configure. We have this in depth look at twinchargers if you want to read more.

Fuelling

You will need to ensure that the engine is not starved of fuel so need to look at the fuelling when you start going beyond 20% of a torque increase.We would recommend you to over specify your injectors flow rate.

The rule of thumb is to add 20% to the flow rate when fitting an injector, this allows for injector deterioration and provides a little 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.

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 improve your exhaust if the current exhaust is creating a restriction in flow.

On most factory exhausts you'll find your flow rate is still good 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 help equal out the flow of air through the engine.

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

Typically exhaust restrictions can be located the emissions filters 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 4G6

The 4G6 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 4G6, 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 4G6 engine please join us in our friendly forum where you can discuss tuning options in more detail with our 4G6 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 parts 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 4G6 tuning guides which get regular updates and revisions.

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