Tuning the Mitsubishi 4G63

"Comprehensive guide to tuning the Mitsubishi 4G63 engine!"

The 4G62 is one of the most popular tuning projects out there, if our readers are anything to go by.

Rallyart showed what can be done with the right mods and we have an engine with one of the most extensive catalogue of aftermarket parts for it.

So let's consider 4G63 tuning and point out the best modifications. Mitsubishi 4G63 offer good returns when tuned and with the best performance parts like remaps, turbo upgrades and camshafts you will substantially improve your driving pleasure.

When talking about the best best for your 4G63 engine, we are going to focus on the tuning parts that give the biggest return for your cash.

Altering your 4G63 cam will make a dramatic difference to the engine engines power. Choosing a higher performance cam profile raises the engines power accordingly.

NB: Fast road cams usually bump the performance throughout the rpm band, you may lose a little low down bhp but top end will improve.

Race cams, bump the top end band but as a result the car will not idle smoothly and low end power nearly always suffers.

In a road car should ideally to optimize your power band to your driving style.

I'd be gobsmaked if you have found a 4G63 Competition camshaft is a pleasure to live with when on the daily commute.

Different 4G63 engines respond better to less aggressive cam durations so set your engine up on a rolling road.

The ECU mapping and fuelling also have an effect on the bhp gains you'll hit.

Altering valve durations can alter the bhp 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, Sports exhaust manifold, Panel air filters, Intake headers, Drilled & smoothed airbox, Remaps/piggy back ECU.

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

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

The 4G63 engines respond well to upgrades and we see that there is a lot of upgrades and performance parts around.

Mapping allows a tuner to release the full potential of all the tuning mods you've fitted to your 4G63.

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

It is the whole point to any engine upgrade job to force more fuel and air into each cylinder

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

Shape and flow rate of the Plenum can make a large effect on to fuel delivery on the 4G63.

Many mass produced engine intake manifold are in desperate need of an upgrade, although some makers provide decently flowing intake manifold.

Fitting big valve kits, getting 4G63 port enlargement and head flowing will also improve torque, and importantly will make space for increasing the 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 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 massive power gains.

If your motor is fitted with a turbocharger upgrades are going to net you a larger power gain and most turbo charged engines are built with many forged and stronger components.

There are common areas of failure for every engine, with some being over specified and some only just able to handle stock power

Discover these limits and fit higher quality crank and pistons to cope with the power.

It's not unheard of people spending a loads of money on turbo upgrades on the 4G63 only to experience the motor explode when it's used on the roads.

Big capacity turbos often suffer low end lag, and little turbos spool up more quickly but don't have the peak end power band gains.

Thankfully the selection of turbo chargers is always moving on and we are seeing variable vane turbo chargers, allowing the vane profile is altered according to speed to lower lag and increase top end performance.

Twin scroll turbo chargers divert the exhaust gases into two channels and push these at differently profiled vanes in the turbo. They also boost the scavenging effect of the engine.

It is common that there is a restriction in the air flow sensor MAF/MAP on the 4G63 when a lot 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 sapped performance at a much lower level.

Adding a supercharger or additional turbo will make large torque gains, although more difficult to configure. We have this article on twincharging if you want to read more.

Fuelling upgrades and mods

You will need to ensure that the engine is not starved of fuel so need to increase the fuelling when you start going beyond 20% of a bhp increase.We strongly recommend you to over specify your injector capacity.

As a rule of thumb add 20% to the flow rate when fitting an injector, which takes into account injector deterioration and provides 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 only need to to replace your exhaust if your exhaust is actually causing a restriction in flow.

On most factory exhausts you'll see the exhaust flow rate is still 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 can help equal out the flow of gases through the engine.

But if the exhaust pipe is too big, ie: it's over 2.5 inches bore, you will lose a great deal of your flow rate and end up sapping power and torque.

Typically exhaust restrictions are in the emissions filters installed, so adding a freer flowing performance alternative will help avoid this restriction.

Weak spots, Issues & common problem areas on the 4G63

The 4G63 engines, if regularly serviced and maintained, are generally very reliable and have few issues.

Regular oil changes are vital on the 4G63, particularly when the engine has been modified and is putting down more power than the manufacturer intended.

History of the Engine

4G63 G63B 1,997 cc (2.0 L)

For more information 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.

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 upgrades were the most effective for them, it helps us improve our recommendations and articles to reflect current trends in modifications and ensures that our 4G63 guides and tips are kept up to date.

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