Mitsubishi 4G9 Tuning

"All you need to know about tuning the Mitsubishi 4G9 engine!"

TorqueCars will provide a guide to 4G9 tuning and provide tips on the optimum mods that work. One engine that keeps cropping up in emails and questions we get sent, is the 4G9, and what enhancements work best on it. So this guide has been assembled which covers our go to modifications that you should tune and outline which modifications we feel are the best.

Mitsubishi 4G9 make a good tuning project and with the ultimate modified enhancements like a remap, turbo kits and camshafts you will really enhance your driving pleasure.

Our aim here is to detail the best approach to 4G9 tuning and show the optimum modifications for your car. Mitsubishi 4G9 make awesome project cars and with carefully chosen uprated upgrades like remapping, turbo improvements and camshafts you will dramatically improve your driving pleasure.

History, Power & Specs of the 4G9 Engine


115 PS (85 kW; 113 hp) at 6,000 rpm and 135 Nm (100 lbft) at 5,000 rpm
carbureted model, with 97 PS (71 kW; 96 hp) at 6,000 rpm and 126 Nm (93 lbft) at 3,500 rpm


4G92P SOHC 16 Valve
Maximum Output (1) - 83 kW (113 PS; 111 bhp) at 6,000 rpm, and 137 Nm (101 lbft) at 5,000 rpm
Maximum Output (2) - 69 kW (94 PS; 93 bhp) at 5,500 rpm, and 135 Nm (100 lbft) at 4,000 rpm
(1): Early European and JDM versions with 20°/42° intake and 54°/2° exhaust valve timing

4G92 DOHC 16 Valve

Maximum Output - 108 kW (147 PS; 145 bhp) at 7,000 rpm
Maximum Torque - 149 Nm (110 lbft) at 4,500 rpm

4G92-MIVEC DOHC 16 Valve

Maximum Output - 125 kW (170 PS; 168 bhp) at 7,500 rpm
Maximum Torque - 167 Nm (123 lbft) at 7,000 rpm

Mitsubishi Lancer
Mitsubishi Mirage
Mitsubishi Carisma
Proton Wira
Proton Satria

4G93 SOHC 16 Valve MPI

Maximum Output - 86 kW (117 PS; 115 bhp)
Maximum Torque - 166 Nm (122 lbft)

4G93 SOHC 16 Valve Carb

Maximum Output - 74 kW (101 PS; 99 bhp)
Maximum Torque - 154 Nm (114 lbft)

4G93 DOHC 16 Valve MPI

Maximum Output - 103 kW (140 PS; 138 bhp) @ 6,500 rpm
Maximum Torque - 167 Nm (123 lbft) @ 5500 rpm

4G93T DOHC 16 Valve Turbo

Maximum Output - 143 kW (194 PS; 192 bhp) @ 6,000 rpm (Upgraded to 151 kW (205 PS; 202 bhp) in 1994, and again to 158 kW (215 PS; 212 bhp) in 1995)
Maximum Torque - 270 Nm (199 lbft) @ 3,000 rpm (Upgraded to 275 Nm (203 lbft) in 1994, and again to 284 Nm (209 lbft) in 1995)

4G93 DOHC 16 Valve GDI

Europe: 88 kW (120 PS; 118 bhp) @ 5,250 rpm / 90 kW (122 PS; 121 bhp) @ 5,500 rpm / 92 kW (125 PS; 123 bhp) @ 5,500 rpm Europe: 174 Nm (128 lbft) @ 3,500 rpm / 174 Nm (128 lbft) @ 3,750 rpm

Japan: 96 kW (131 PS; 129 bhp) @ 5,500 rpm / 96 kW (131 PS; 129 bhp) @ 6,000 rpm / 110 kW (150 PS; 148 bhp) @ 6,500 rpm apan: 181 Nm (133 lbft) @ 3,500 rpm / 177 Nm (131 lbft) @ 3,750 rpm / 178 Nm (131 lbft) @ 5,000 rpm

4G93 DOHC 16 Valve GDI Turbo

Maximum Output - 118 kW (160 PS; 158 bhp) @ 5,200 rpm / 121 kW (165 PS; 162 bhp) @ 5,500 rpm
Maximum Torque - 220 Nm (162 lbft) @ 3,500 rpm / 220 Nm (162 lbft) @ 3,500 rpm

  • Mitsubishi Space Wagon
  • Mitsubishi Space Star
  • Mitsubishi Carisma
  • Mitsubishi Lancer
  • Mitsubishi Mirage
  • Mitsubishi FTO
  • Proton Wira
  • Proton Satria
  • Proton Putra
  • Mitsubishi Colt GTI
  • Mitsubishi Galant 1996
  • Mitsubishi Pajero iO / Pajero Pinin / Shogun Pinin / Montero iO /
  • Pajero TR4
  • Brilliance BC3
  • Brilliance BS6
  • Brilliance BS4
  • Volvo S40
  • Volvo V40

Tuning the Mitsubishi 4G9 and best 4G9 performance parts.

Best 4G9 upgrades

The ultimate 4G9 upgrades on an engine are sensibly the ones that give the best value for money.

We won't be swayed by popular 4G9 upgrades, they need to be cost effective.

Significant gains on the 4G9 can be made from cam upgrades. Altering the cam profile alters the intake and exhaust durations on the engine and can dramatically change the bhp and power output.

Fast road camshafts usually increase the bhp across the rev band, you could drop a little bottom end bhp but the high end rpm power will be higher.

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

A Race cam is not great on the daily commute, because the lumpy idle will make the car prone to stall and smooth driving at low rpm becomes impossible. If you are developing a track car this doesn't matter as you are in the high end of your RPM range anyway and that is where you want the power to be.

You should ideally optimize your bhp range to your cars usage so for a car driven daily stick with a mild fast road 4G9 cam

Different 4G9 engines respond better to more aggressive camshaft durations check your engine on a rolling road.

The engine timing and fuelling also will make differences on the power gains you'll make.

Extending exhaust or intake durations can alter the power 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 keep up with our latest YouTube content and subscribe.

Best mods for your 4G9

  1. Engine Tunes - A tune/remap provides the most advantage compared to cost, aftermarket ECU upgrades, and piggyback ECUs are all alternatives.
  2. Fast road cams are generally the biggest mechanical mod upgrade, but they must be setup by someone who knows what they are doing and they are not always easy to source but you might find a local firm to regrind a stock camshaft.
  3. Turbo upgrades - 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 you'll see massive gains.
  4. Internal engine mods - crank, pistons, conrods & compression ratio including balancing and blueprinting

4G9 Tuning Stages

Typical stage 1 mods often include:
Sports exhaust header/manifold, Panel air filters, Intake manifolds, Remaps/piggy back ECU, Fast road camshaft, drilled & smoothed airbox.

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

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

Review your options and then buy your modifications and set yourself a power target to avoid costly mistakes.

ECU mapping will help fully realize the full potential of all the upgrades you've done to your 4G9.

(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 results may differs on the upgrades you've fitted and the condition of your engine.

Forcing air and fuel into each cylinder is the main goal to any engine tuning job.

The intake plenum flow the air during the suck phase from the filter and allow it to be pulled into the engine cylinders.

Design and rate of flow of the Intake manifold can make a noticeable change to fuel mixing and power on the 4G9.

It's not uncommon that manifolds are begging for aftermarket tuning parts, although some OEM provide reasonably good headers.

Adding a 4G9 larger valve kit, getting port matching and head flowing will also improve bhp, & more importantly will permit increasing the bhp increase on other mods.

4G9 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 4G9

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 car is fitted with a turbocharger modifications are relatively easy and turbocharged engines are made with stronger components.

There are tuning limits for every engine, with some being over specified and some only able to handle stock powerWe recommend you find these limits and upgrade to better quality crank and pistons to survive the power.

It's not unheard of car owners spending a a stack of money on turbo charger upgrades on the 4G9 only to experience the 4G9 explode soon after it's used on the roads.

Larger capacity turbo units commonly experience low end lag, and small turbo units spool up really quickly but do not have the peak end bhp gains.

In the last 10 years the market of turbochargers is always improving and we commonly find variable vane turbochargers, allowing the vane profile is altered according to speed to lower lag and increase top end torque.

Twin scroll turbochargers divert the exhaust flow into a couple of channels and flow these at differently profiled vanes in the turbo charger. They also improve the scavenging effect of the engine.

You'll commonly see there is a restriction in the air flow sensor (AFM/MAF/MAP) on the 4G9 when a lot more air is being drawn into the engine.

We see 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor sapped torque at a much lower level.

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


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 performance increase.It is important to over specify your flow rate on the injectors.

As a rule of thumb add another 20% when fitting an injector, which takes into account injector deterioration and affords 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.

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

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

4G9 Performance Exhausts

You should look to boost your exhaust if your current exhaust is creating a restriction in flow.

On most factory exhausts you'll find 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.

Please dont run with the widest exhaust you can buy this will reduce the exhaust flow rate - the best exhausts for power gains are usually between 1.5 to 2.5 inches. It is the shape and material more than the bore size.

Typically exhaust restrictions are traced to the catalyst and filters installed, so adding a higher flowing race alternative such as a sports catalyst pretty much removes this restriction, thanks to it's larger size and surface area, and will effectively raise the performance to levels you would expect without having a catalyst installed, but keeps the car road legal.

Weak spots, Issues & problem areas on the 4G9

The 4G9 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 4G9, 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 4G9 engine please join us in our car forums where you can discuss 4G9 tuning options in more detail with our 4G9 owners. It would also be worth reading our unbiased Mitsubishi tuning articles to get insights into each modification and how effective they will be for your car.

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