4G15 is one of the living legends and the oldest Japanese engines we have presently. Mitsubishi developed other engines through the 4G15 and is the flagship of the then-formed Orion engine family.
Engines inside the Orion family include 4G13, 4G11, 4G12, 4G15, 4G16, 4G18, and 4G19. 4G15s were first installed in the Mitsubishi Mirage in 1989, where it replaced the G15B engine.
4G15 was eventually removed from the main roster of Mitsubishi cars following the replacement of the 4A91 engine. But they are still produced and used today by other car manufacturers, especially in China since 2005.
These newly-produced engines are made by GAC Mitsubishi Motors, a collaboration project from the Hunan province in Southern China since April 2017.
And with that, let us start by knowing the 4G15 engines more. Let’s get right to it.
Here are some information and an overview of the 4G15 engine:
Engine Specifications and Design
- Production Run: 1989 – Present
- Cylinder Head Material: Aluminum
- Cylinder Block Material: Cast-iron
- Configuration: Inline-4
- Bore: 75.5 mm
- Stroke: 82 mm
- Valvetrain: 2 Valves Per Cylinder SOHC, 3 Valves Per Cylinder SOHC, 4 Valves Per Cylinder SOHC, 4 Valves Per Cylinder DOHC
- Displacement: 1.5 L
- Compression Ratio: 9.0 – 10. 5
- Weight: 254 lbs.
- Max HP: 180 HP
- Max Torque: 181 lb-ft at 3,500 RPM
Mitsubishi 4G15 is an inline-four engine that was installed in the Mitsubishi Mirage and had a displacement of 1.5 Liters. It replaced the previous G15B engine and shared the same cylinder block as its smaller brother, the 4G13 engine.
4G15s has four succeeding variants, which, at times, were concurrent with each other to serve as an option for those who prefer a particular design of their 4G15 engine.
Going inside the block, 4G15s has a deck height of 201 mm, 82 mm stroke, and a cylinder bore of 75.5 mm, which was increased from 71 mm to expand the displacement to 1.5 L.
In early 4G15 releases, it featured a 12-valve SOHC cylinder head with three valves per cylinder (two for intake and 1 for exhaust) that produces 90 hp, 99 hp on the Japanese Market, and 90 lb-ft of torque at 3,000 RPM.
It also used either the carburetor fuel system or single-point fuel injection and a compression ratio of 9.2. However, Mitsubishi produced a 4G15 version with a gasoline multi-port injection on the 1993 Mirage model, which has 94 hp of power.
Later on, in 1991, Mistubishi added a natural-gas-powered version and introduced the MVV (Mitsubishi Vertical Vortex), a new lean-burn technology that is a linear air-fuel ratio gas oxygen sensor.
Since 1995, Mitsubishi has used the 16-valve DOHC heads with four valves per cylinder. This engine produced 110 hp at 6,000 RPM and 101 lb-ft of torque at 3,000 RPM.
In the following years, Mitsubishi continues to upgrade 4G15 engines, and in 1998, a DOHC version with fuel-injection modification was produced and called 4G15 GDI that provides 100 hp and lb-ft of torque at 3,000 RPM.
A DOHC MIVEC turbo variant of the 4G15 GDIs appears on the Mitsubishi Colt Series, particularly on the latest Colt-version R that delivers 163 hp with some exhaust enhancements. This engine is still in production today.
In 2004, Mitsubishi introduced the most-sought and the most powerful version of the 4G15 engine through the Mitsubishi Colt Ralliart. With the intent to compete in mind, this engine was made for sports models as it produces a total output of 197 hp.
It has a lower compression ratio, oil squirters for better combustion, and an intercooler-equipped turbocharger.
4G15 logged a staggering 997,000 miles in a 1998 Mitsubishi Mirage sedan as proof of its reliability.
Another version of the 4G15 is the 4G15 8-Valve SOHC, a carburetor type of engine with a compact type combustion chamber. It produces 76 hp, 94 lb-ft of torque, and a 9.4 compression ratio.
It is an analog of the Mitsubishi G15B engine, which is equipped with jet valves, jet springs and carries the mechanical engine specifications of the said engine.
- Mitsubishi Colt / Lancer (1983, 1987, 1991, 1995, 2000)
- 1989 – 1995 Mitsubishi Mirage (US)
- 1996 – 2002 Mitsubishi Mirage (US)
- 1988 – 1995 Dodge Colt
- 1988 – 1996 Eagle Summit
- 1986 – 1994 Hyundai Excel (US)
- 1987 – 1992 Proton Saga (C20)
- 1993 – 2009 Proton Wira / Persona (C90)
- 1994 – 2005 Proton Satria / Persona Compact (C90)
- 1998 – 2003 Mitsubishi Dingo
- 2002 – 2009 Proton Arena / Jumbuck
- 2004 – 2006 Smart Forfour
- 2005 – 2010 BYD F3 (4G15S, EFI, distributor-less ignition)
- 2005 – 2019 Mitsubishi Colt T120SS MPi (Indonesia)
- 2005 – 2009 Mitsubishi Maven
- 2007 – 2015 Great Wall Cowry
- 2008 – 2013 Great Wall Florid
- 2008 – 2009 Soueast V3 Lingyue
- 2008 – 2010 Zotye 2008 / Nomad
- 2009 – 2013 Youngman Lotus L3
- 2010 – 2016 Great Wall Voleex C50
- 2012 – 2017 Haval H1
- 2014 – 2016 Geely MK
- 2015 – Present Haval H6/Haval H6 Sport Haval H6 Coupe
- 2016 – Present Haval H2
- 2016 – Present Yusheng S330
- 2017 – Present Zotye T300
- 2018 – Present Zotye T500
- 2018 – Present Zotye T600
- Geely Yuanjing X3
- Changan CS35
- 2009 – Present Emgrand EC7
- 2018 – Present Ford Territory (China)
Engine Upgrades, Tuning, and Modifications
You have two options to make the 4G15 engines become faster: forced induction and naturally-aspirated. For the latter, you will need to install an aftermarket air filter, 2-inch exhaust system, 60 mm throttle body, 4-2-1 header, and ECU tuning.
These mods will at least give you 20 horsepower, at maximum. You can also buy some aftermarket cams, adjustable cam gears, install new spark plugs, install an additional ITB, high compression pistons, do some head port and polish, and a lighter flywheel.
But all these amounts to a slight difference in power, so this will not be a good option in terms of investment gains.
However, there is still another option, and that is to install a turbo or the forced induction. You will just need to buy a decent turbo kit and turbo manifolds for this, like TF035 turbocharger or its likes; add in some oil feed line and oil drain line and put it in the stock internals.
It would be better if you also had an intercooler, 275 cc fuel injectors, 255 liters per hour fuel pump, turbo piping, 2.5-inch exhaust system, O2 sensor, and an ECU Tuning.
On this kind of setup, the engine might not able to withstand it for long periods of time, so changing the internals is the right thing to do by buying some forged low compression pistons, H-beam rods, ARP head studs, and a head gasket; install oil jets for piston cooling, bigger intercooler, Mishimoto radiator, oil cooler, fuel rail, fuel pressure regulator, 630 cc fuel injector, and a blow-off valve.
Using performance parts and an Evo turbo might push the boost to 350 horsepower. Replace the stock crankshaft with the aftermarket for an added efficiency.
Problems Surrounding 4G15 Engines
As much we wanted to take our engines away from issues and problems, there is no such thing as that. But we can prevent some worst things from happening to our engines by having noticed some weird noises or not-so-normal occurrences.
Here are some issues that might arise on 4G15 engines:
First is the engine won’t start. For those who are living in colder climates, this is prevalent. 4G15s are not good at resisting frosts, though all engines are too. But, the reason might be in the fuel pump, or if the fuel pump is good, sparks plugs might be the problem.
Next is the high oil consumption. High oil consumption correlates to poor oil distribution that leads to this and sometimes leakage. Most commonly occur on older engines around 120,00 miles due to some loose components, standard wear and tear, and poor engine oil quality.
We all know that low levels of oil in the engine can cause a lot of trouble that can result in major problems. Replacing piston rings is a good option, but overhaul is better for a long time.
Unnecessary vibrations. This problem happens when engine mounts are not properly placed. This is too common not only for 4G15s but across 4G1 engines. Try to increase the idle. That might solve the issue.
Another thing is the rough idling. This is due to a worn-out throttle body or its case. Though this is common on 4G1 engines also, it can cause you some trouble. You will just need to replace the throttle body or the case, and that would solve it.
Since 4G15s do not use hydraulic lifters, you need to adjust the valves at least every 60,000 to avoid some ticking noise. The valve clearances are 0.15 mm for intake and 0.25 mm for the exhaust for the hot engine, and 0.07 mm for intake, and 0.17 for exhaust in a cold engine.
Make sure that the timing belts are also replaced at around 60,000 miles to prevent valve bending.
To add to the mentioned above, regular maintenance and habitual checking go a long way for the engine. Use a good quality engine, and don’t forget to take note of the things you need to replace immediately.
4G15 engines are more than a decade long in the industry now, and they gained a lot of respect from their peers. This 4G1 series proven that these engines are reliable and can go head-to-head in terms of economy, power, and reliability.
They continue to do so, for they are still used up until now. It does not have a major problem to mention, and with proper maintenance and regular check-ups, this engine can serve you 400,000 miles or more. Just don’t let it run carelessly, and it will stay for a long time.
I hope that we cleared some clouds in your head regarding the 4G15 engines and their course through time -how they thrived in the past few years. The information regarding the 4G15 engine, design, origins and overall impact on the industry may help you familiarize yourself with the 4G15 more.