Modifying and improving: "4G6 Modifications"

How to modify and upgrade the Mitsubishi 4G6

"Comprehensive guide to tuning the Mitsubishi 4G6 engine!"

Popular tuning sites like TorqueCars are regularly getting messages about how to improve the 4G6 from people wanting to know what are the best tips for 4G6 mods that work. So let us look into Mitsubishi 4G6 upgrades and outline the best upgrades on this great engine and point out some potential pitfalls along the way.

Car Tuning Tips will look into 4G6 tuning and outline the greatest mods that work. Mitsubishi 4G6 are fantastic to work on and with a few sensible tuning upgrades like remaps, turbo upgrades and camshafts you will increase your driving pleasure.

The optimum 4G6 modifications on an engine are obviously the ones that give the best power gain for your hard earned cash.

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

Improving air intake on the 4G6

You need air matched to fuel for an engine to work. If there is a lack of fuel then it will run lean, if there is insufficient air it runs rich sapping power which risks damage to the 4G6. We'll pick up on fuelling later in this article but for now we shall look at air supply.

So the whole point to any engine modification job to pull more air into each cylinder but this has a knock on effect with the air flow sensor.

It is not unusual that there is a limitation in the air flow sensor MAP/MAF/AFM on the 4G6 when loads more air is being sucked into the engine.

When tuning you may well find you need to get an air sensor or flow meter capable of upto 4 bars to cope with quite large power gains, whereas the OEM air sensor limited power at a much lower level.

Engine intake manifolds transmit the air during the suck phase from the air cleaner and allow it to be sucked into the engine cylinders.

Shape and flow characteristics of the Intake headers can make a noticeable difference to to fuel atomisation and engine efficiency on the 4G6.

Most intake are ripe for a performance upgrade, although some makers provide reasonably good intake.

Larger 4G6 valves, doing a bit of 4G6 port enlargement and head flowing will also increase performance, & more importantly will allow you to get an improved performance increase on other modifications.

4G6 performance cam tips.

Some 4G6 engines respond better to more or less aggressive camshaft durations so view each engine as unique.

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

A longer valve duration 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.

Altering your 4G6 cam will make a dramatic difference to the engine power band. Choosing a higher performance cam profile raises the power band accordingly.

NB: Fast road camshafts usually bump the torque throughout the rev range, you might lose a little low end torque but your top end will be better.

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

For a daily driver you need to optimize your torque band to your preferences.

I'd be shocked if you find a 4G6 Competition cam is a pleasure to live with when driving around busy urban areas.

Stage 1, 2 and 3 mods for the 4G6

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 4G6 parts:

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

Stage 2 4G6 parts:

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

Stage 3 4G6 parts:

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

ECU mapping will help to establish the full potential of all the upgrades you've done to your 4G6.

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 the outcome will depend much on the upgrades you've done and the condition of your engine.

Turbo modifications on the 4G6

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 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 impressive power gains.

When the engine has a turbocharger upgrades are giving better power gains and most turbo charged engines are built with strengthened components.

There are weak spots for every engine, with some being over specified and some only able to handle stock power

It is important to find these limitations and install better quality components to cope with the power.

It's not unheard of drivers spending a loads of money on turbo charger upgrades on the 4G6 only to suffer the indignity of watching the car go up in smoke just after it's used on the roads.

Larger upgraded turbos tend to experience low end lag, and low capacity turbos spool up really quickly but won't have the high rpm engines power gains.

Thankfully the market of turbos is always moving on and we now see variable vane turbos, allowing the vane angle is altered according to speed to lower lag and increase top end bhp and torque.

Twin scroll turbos divert the exhaust flow into 2 channels and direct these at differently designed vanes in the turbo. They also help the scavenging effect of the engine.

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

Tips about fuel supply on the 4G6

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 power hike. It makes sense to be generous with your injector capacity.

As a rule of thumb add 20% when specifying an injector, which takes into account injector deterioration and affords a little 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 4G6 performance exhaust upgrades

Only look to boost your exhaust system with an upgraded one is if your exhaust is creating a restriction.

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

But if the exhaust pipe is too large, ie: it's over two and a half inches diameter, you will lose a lot of your flow rate and end up lacking power and torque.

Typically exhaust restrictions come around the catalysts installed, so adding a higher flowing high performance alternative will help avoid this restriction.

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

Faults issues and things to look out for on the 4G6

Like most engines an 4G6, 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 4G6, failure to do this will exacerbate engine wear, on a tuned 4G6 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 4G6 why not pop over to the forums at TorqueCars where you can chat about 4G6 tuning options and read about others projects who may be planning to do similar modifications on their 4G6.

We need your help to complete and improve this page, so do give us your feedback in the comments box below.

We want to know your experiences with mods on your 4G6, it helps us improve our tips and keeps us current so please use the comments box to drop a tip.

This entry was posted under Makes and Models. Tags: engine, mitsubishi
You can leave a response below or join our forum to discuss this article and car modification in detail with our members.

If you liked this page please share it with your friends, drop a link to it in your favourite forum or use the bookmarking options to save it to your social media profile.

Check out TorqueCars new YouTube channel, and see their awesome new content...