Tuning the Mitsubishi 4G6

"Comprehensive guide to tuning and performance parts on the Mitsubishi 4G6 engine!"

Please note we have a 4G63/G63B specific article here- 4G63 Tuning as this is quite a different proposal from the NASP 4G6 blocks.

Herein we consider 4G6 tuning and show the greatest modifications. Mitsubishi 4G6 provide a fun base for your project and with carefully picked motorsport parts like ECU maps, turbo improvements and camshafts you will dramatically enhance your driving opportunities.

The greatest 4G6 parts on an engine are typically the ones that give the best value for money.

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

Significant gains on the 4G6 can be made from camshaft upgrades. Altering the camshaft profile alters the intake and exhaust durations on the engine and can dramatically change the torque and power output.

NB: Fast road camshafts normally boost the bhp across the rpm range, you could sacrifice a little low end bhp but your top end will improve.

Competition camshafts, boost the top end 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 driving around busy urban areas.

You should ideally optimize your bhp range to your typical driving style so for a daily driver stick with a shorter duration 4G6 camshaft

Different 4G6 engines respond better to different cam durations so set your engine up on a rolling road.

The engine timing and fuel pump and injectors also will say much on the torque gains you'll achieve.

Longer 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.

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

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

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

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

Mapping should help to unlock the full potential of all the parts you've fitted to your 4G6.

It will usually give around 30% more power on turbocharged vehicles and you can expect to see around 15% on NASP engines, but your mileage will rely on the parts you've done and the condition of your engine.

It is vital to any car tuning task to get air and fuel into the 4G6 engine

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

Design and flow characteristics of the Plenum can make a noticeable improvement to fuel engine efficiency on the 4G6.

Many mass produced engine air intake manifolds are needing aftermarket tuning parts, although some OEM provide reasonably well designed air intake manifolds.

Adding a 4G6 larger valve kit, getting 3 or 5 angle valve jobs and porting and head flowing will also improve bhp and torque, and more importantly will afford you an improved bhp and torque increase on other parts.

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 4G6

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.

If a car is fitted with a turbocharger mods are simpler to install and most turbo charged engines are built with stronger components.

However every engines will need better parts at higher power limits

Research these limitations and fit higher quality crank and pistons to handle the power.

It's not unheard of guys spending a lots of money on turbocharger upgrades on the 4G6 only to experience the motor explode just after it's used on the roads.

Bigger turbo units will usually experience no power at low rpm, and smaller turbo units spool up much more quickly but do not have the peak rpm power band gains.

In the last 10 years the world of turbo units is always increasing and we now see variable vane turbo units, allowing the vane angle is altered according to speed to lower lag and increase top end torque.

Twin scroll turbo units divert the exhaust flow into two channels and push these at differently designed vanes in the turbocharger. They also help the scavenging effect of the engine.

It is common that there's a limit in the air flow sensor MAP/MAF/AFM on the 4G6 when loads more air is being sucked into the engine.

You'll see that 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor sapped power at a much lower level.

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

Fuelling upgrades and mods

You will need to ensure that the engine is not starved of fuel so will need to pay attention to the fuelling when you start going beyond 20% of a bhp and torque increase.Don't forget to over specify your injectors flow rate.

The rule of thumb is to add 20% when buying an injector, this allows for injector deterioration and allows you 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.

Exhaust upgrades and mods

You may need to upgrade your exhaust if the existing exhaust is actually creating a restriction.

On most factory exhausts you'll find the exhaust 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.

Sports exhausts generally help improve air flow out of the engine but avoid an exhaust that is too big or you may end up will reduce the flow rate. Stick to 1.5 to 2.5 inches for best results.

Common exhaust restrictions typically happen through the catalyst and or DPF filters which manufacturers fit, especially as they start to get worn and carbon builds up, so adding a freer flowing high performance alternative will help avoid this restriction.

Weak spots, Issues & common problem areas on the 4G6

The 4G6 engines, if regularly serviced and maintained, are generally very reliable and have few issues.

Regular oil changes are vital on the 4G6, particularly when the engine has been modified and is putting down more power than the manufacturer intended.

History 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


See separate article for this engine


  • 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.

For more information 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.

We need your help improving this article, so please send us your feedback in the comments box below and pass on any tips, points or facts we have wrong or have not covered.

We really like hearing from our readers, and hearing about which parts were the most effective for them, it helps us improve our recommendations and articles to reflect current trends in modifications and ensures that our 4G6 guides and tips are kept up to date.

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