Mitsubishi 4G93 engine

1. Specifications
2. Overview, problems
3. Performance tuning

Specs

Mitsubishi 4G93 engine reliability, problems and repair

Let’s talk about the fairly popular 1.8-liter Mitsubishi engine that has been produced for 20 years with designation 4G93. The lower part of the engine (the cylinder block) is made of cast iron, its block height is 208.75 mm, the cylinder bore is 81 mm, the piston stroke is 89 mm, the rod length is 133.35 mm, and the piston compression height is 30.8 mm. All this results in the displacement of 1.83 liters.
You can buy cars with various modifications of 4G93 cylinder heads. The simplest is the SOHC 16 valve head, which is installed with carburetor injection (101 HP) or multipoint fuel injection MPI (117 HP).
The 240/252 deg camshaft is found here.
The second variant is the DOHC 16 valve head, which could be either with MPI (140 HP) or with the direct injection system GDI (120 HP and 131 HP).The 255/261 deg camshaft is used in this engine.
The third variant is the turbocharged version with a DOHC 16 valve GDI head. It featured a high compression ratio of 10.0:1, a small MHI TF035HM-12T-5 turbocharger, and the boost pressure is only 4.5 psi (0.3 bar).
The most powerful and “savage” are turbocharged engines with the DOHC MPI 16 valve head. These engines had the compression ratio reduced to 8.5:1, a Mitsubishi TD04L-13G-5 turbocharger, and the power of 194 HP at 6,000 rpm, the torque of 270 Nm at 3,000 rpm. These engines are known as 4G93T Gen 1.
In 1996, the compression ratio increased to 9.1:1, and the power grew up to 205 HP, and later to 215 HP. Such models are known as 4G93T Gen2. These turbocharged 4G93’s have a boost pressure of 11.3 psi (0.78 bar). They use 390 CC fuel injectors.
You can see such an engine in Lancer GSR.
I skipped the version with a carburetor since it is a very old modification, and it is not interesting for anyone today.
All the heads I mentioned above use a timing belt that is to be replaced after 60,000 miles (90,000 km) to avoid breakage.
All the heads use hydraulic tappets, so you don’t have to worry about valve adjustment.
The firing order is 1-3-4-2.
The Mitsubishi company has created several other engines using 4G93: 2.0 liter 4G94, 1.6 liter 4G92, and the small 1.5 liter 4G91.

Mitsubishi 4G93 engine problems and malfunctions

1. Knocking sound in the engine. It is usual for 4G93 in the countries where poor quality oil. Poor quality oil damages hydraulic lifters and they are to be replaced.
2. High oil consumption. Your engine is many years old, and for an old engine, it is a typical situation. You have to disassemble the engine and see whether an overhaul is required, or you can just replace the piston rings and valve stem seals. Most likely, you need a complete overhaul.
3. Idle problem. This problem is usually found in GDI engines, the reason is clogged high-pressure fuel pump, and it should be cleaned. The second reason is the dirty throttle body, clean it.
The third reason is the idle air control valve, try to replace it.

However, that’s not all, the 4G93 GDI engines have issues with the EGR valve. For this reason, the intake manifold is constantly clogged and needs regular cleaning. In the locations with heavy frosts, spark plugs are frequently filled with fuel. GDI engines love high-quality oil, good fuel, and regular maintenance.
In general, it is a common average engine with medium reliability.

Engine number location

Mitsubishi 4G93 engine tuning

4G93 MIVEC

Building a 4G93 with MIVEC head means giving the engine what it lacks. You have to buy a 4G92 MIVEC head, a head gasket, 4G92 pistons, stock rods, a 4G92 intake manifold, a 4G94 timing belt, Lancer GSR fuel injectors (390 cc), and a 4G92 ECU. Install the 4G92 MIVEC head on the 4G93, install all the other components, and you will get about 180 HP on the flywheel. Want 200+ HP? In this case, you will need some NA mods: a cold air intake system, a 63 mm throttle body (or ITB), a Skunk2 intake manifold, 272 cams (or better), an adjustable cam pulley, heavy-duty valve springs, a 4-2-1 header, a 2.5-inch exhaust system, a lightened flywheel, 360 cc fuel injectors, a fuel regulator, and a Haltech ECU (or other). You can also port and polish the head, and all these modifications are to be configured.

Turbo

To build a turbocharged 4G93, you need the turbo kit from 4G93T (TD04L turbocharger). With these performance upgrades, you can customize the boost pressure to 1 bar, and your car would still be comfortable in daily use. You can install a big turbo, for example, EVO turbocharger (TD05H-16G) with a large intercooler, 2-inch piping, an EVO throttle body, a Walbro 255 fuel pump, a fuel rail, 630 cc fuel injectors, a turbo manifold, and a 2.5-inch exhaust system.
But don’t forget to install oil squirters into your N/A cylinder block and buy forged internals or use the 4G93T pistons and rods.
This way, you will get 300++ HP.
You are lucky if you have a 4G93T, in this case, boost up will be enough. The 4G93T GDI version has low boost pressure; it may be raised to 0.8 bar; you will also need to buy an EVO intercooler, a 2.5-inch exhaust system, and tune the ECU — all this will give you about 190 HP. Next, you have to replace the stock turbocharger with a regular MHI TD04L, add EVO fuel injectors, an EVO fuel pump, an EVO oil cooler and an EVO throttle body (60 mm). Yes, it will be all from Evolution, because these components are designed for high power.