Modding uprating the Mitsubishi 4G63 engine!

Tuning guide "4G63 Modifications"

4G63 Modifications Guide

How to modify and upgrade the Mitsubishi 4G63

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

TorqueCars are always seeing threads asking about how to improve the 4G63 from people wanting to know what are the best tips on 4G63 power upgrades. So let us look into Mitsubishi 4G63 modifications and outline the best modifications on this great engine and point out some common pitfalls along the way.

The Mitsubishi 4G63 make awesome project engines and with the optimum upgrades like ECU maps, turbo kits and camshafts you will certainly enhance your driving fun.

Our aim here is to review and look at 4G63 tuning and outline the best modifications.

Just because particular tuning mods are are common on 4G63 it doesn't mean it is good, we will concentrate on the best tuning mods that will give your 4G63 the best power gain for you money.

Without us subscribing to the misaprehension of 'if it's shiny and makes more noise it must be good' you seem to get in many tuning magazines and on car forums'.

4G63 induction kits

Improving air intake on the 4G63

You need air matched to fuel for an engine to work. If there is little supply of fuel then it will run lean, if there is insufficient air it runs rich resulting in lost power which risks damage to the 4G63. We'll pick up on fuelling later in this article but for now we shall look at air supply.

So the primary aim to any engine performance tuning job to force fuel and air into each cylinder but this has a knock on effect with the air flow sensor.

It is common that there's a limit in the air flow sensor (AFM/MAF/MAP) on the 4G63 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 sapped bhp at a much lower level.

Air Intake manifolds carry the air during the suck phase from the intake filter and allow it to be drawn into the engine cylinders.

Design and rate of flow of the Intake headers can make a noticeable effect on to fuel atomisation and engine efficiency on the 4G63.

Many mass produced engine intake are in dire need of an upgrade, although a few OEM provide reasonably good intake.

Increasing the 4G63 valve size, getting 4G63 port enlargement and head flowing will also lift torque, and significantly will make space for a better torque increase on other tuning parts.

4G63 performance cam tips.

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

The map and fuelling also will make differences on the bhp gains you'll achieve.

Longer 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.

Significant air intake, and exhaust improvements on the 4G63 can be made from camshaft upgrades. Changing the camshaft profile alters the intake and exhaust durations on the engine and can dramatically change the power band and power output.

NB: Fast road cams tend to boost the power through the rpm band, you could sacrifice a little low down bhp but top end will be lifted.

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

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

You should ideally optimize your engines power to your cars usage so for a car used daily stick with a fast road 4G63 camshaft

Stage 1, 2 and 3 mods for the 4G63

Before we break the best tuning upgrades down into stages of tune, let's list the most effective tuning upgrades for you.

  1. Suspension Upgrades - always improve your cars handling
  2. Brake Upgrades - Even before adding power improve those brakes
  3. Intake - make sure the intake is not restricted, use filters and intake upgrades to improve this
  4. Exhaust - as with 3 ensure there is not restriction in the exhaust, cats are the usual bottleneck
  5. Tunes - remapping, piggyback ECU's and aftermarket ECU's can all make decent gains
  6. Fuelling - when you've increased power you'll need to match this with more fuel
  7. Turbo upgrades - Improving the intake with a large turbo and better flowing intercooler will be the biggest power gain you'll see (but one of the most complex).

This video guide to tuning cars is a great starting point to work from in your project.

Stage 1 4G63 parts:

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

Tuning tips and articles Engine tuning Transmission tuning Care care Intake & exhaust mods Improve handling Forums

Stage 2 4G63 parts:

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

Stage 3 4G63 parts:

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

The 4G63 power trains respond well to mods and thankfully there are increasing numbers of parts and performance parts about.

Mapping allows a tuner to unlock the full potential of all the tuning parts you've done to your 4G63.

You will typically expect to see gains of approximately 20-30% more power on turbocharged vehicles and you can expect to see around 15% on NASP engines, but figures achieved often depend much on the tuning parts you've applied and the condition of your engine.

Turbo modifications on the 4G63

To get a turbo working on a NASP engine there is a lot involved, from lowering compression ratio to improved fuel supply and mapping, so we have found a great guide to helpavoid the common pitfalls or end up with an unfinished project because you were not told what you were getting into by doing this on the 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 major power gains.

When your motor is turbocharged, tuning mods are simpler to install and turbocharged engines will have many forged and stronger components.

However you will find an engines have weakspots

It is important to find these limits and fit stronger pistons, crank and engine components to utilize the power.

There are many guys spending a loads of money on turbo upgrades on the 4G63 only to experience the 4G63 catastrophically fail when it's used on the roads.

Larger capacity turbochargers tend to suffer low end lag, and smaller turbochargers spool up much more quickly but do not have the peak end bhp gains.

In the last 10 years the choice of turbo chargers is always increasing and we now see variable vane turbo chargers, allowing the vane profile is altered according to speed to lower lag and increase top end power.

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

Beefing up the air intake by adding a supercharger or additional turbo will help you achieve very large torque gains, although more complex to configure. We have this article on twincharging if you want to read more.

Tips about fuel supply on the 4G63

When you increase the bhp and torque you will need to uprate to the fuel system.

More bhp and torque needs more fuel. We strongly recommend you to over specify your injectors flow rate.

The rule of thumb is to add 15% when buying an injector, this accounts for injector deterioration and provides a bit of spare capacity should the engine need more fuel.

Don't forget that different fuel grades will usually require different settings, a high octane fuel will burn more efficiently than lower octane fuel for example. A car will trim fuel supply to keep within the ideal air fuel mix but at the extreme ends you may need to adjust your injector capacity, or the mapping or you'll get flat spots and potential lean or rich fuel issues..

Recommended 4G63 performance exhaust upgrades

The only time you should look to boost your exhaust system with an upgraded one is if your current exhaust is creating a restriction in flow.

On most factory exhausts you'll see the exhaust flow rate is still good even on modest power gains, but on a serious tuning project with a big boost in power you will certainly need to get a better flowing exhaust.

Sports exhausts can usually air flow out of the engine but avoid an exhaust that is too wide or you may end up will reduce the flow rate. Stick to one and a half to two and half inches as a rule of thumb.

Typically exhaust restrictions are traced to the catalyst installed, so adding a better flowing performance alternative will help avoid this restriction.

Decatting (NB:catalysts reduce harmful engine emissions) is illegal in most countries and regions.

Faults issues and things to look out for on the 4G63

Like most engines an 4G63, should have few issues if it gets properly serviced and looked after.

We cannot stress enough the need for oil changes with the correct grade of oil on the 4G63, failure to do this will exacerbate engine wear, on a tuned 4G63 this is more important than ever and close attention should be paid to your maintenance schedule.

If you are interested in learning more or getting impartial tuning advice for your 4G63 why not pop over to the forums at TorqueCars where you can chat about 4G63 tuning options and read about others projects who may be planning to do similar modifications on their 4G63.

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