The 2.4-liter Hyundai G4CS engine was produced from 1986 to 2007 under license from Mitsubishi and was essentially a copy of the 8-valve version of the Japanese power unit under the index 4G64. Basically, the motor was put on the minibus Starex, but it is also found on passenger cars.
Characteristics of Hyundai-KIA G4CS
| Parameter | Value |
|---|---|
| Manufacturing | Ulsan Plant |
| Engine brand | Sirius |
| Years of production | 1986-2007 |
| Cylinder block material | Cast iron |
| Power system | Injector |
| Type | Ready |
| Number of cylinders | 4 |
| Valves per cylinder | 2 |
| Piston stroke, mm | 100 |
| Cylinder diameter, mm | 86.5 |
| Compression ratio | 8.5 |
| Engine displacement, cc | 2351 |
| Engine power, hp/rpm | – 100/4000 (L4CS) |
| – 114/4500 | |
| – 117/4500 | |
| – 130/4500 | |
| Torque, Nm/rpm | – 178/2000 (L4CS) |
| – 189/3500 | |
| – 193/3500 | |
| – 182/4000 | |
| Motor weight, kg | ~185 |
| Oil consumption, gr./1000 km | To 1000 |
| How much oil in the engine, l | 4.0 |
| Oil change is carried out, km | 7,000-10,000 |
| Engine life, thousand kilometers | – According to the factory data: – |
| – In practice: 400+ | |
| Tuning, hp | – Potential: ~300 |
| – Without loss of resource: – |
Cars with G4CS engine
| Make and model | Generation (code) | Years of production |
|---|---|---|
| Hyundai Grandeur | 1 (L) | 1986 – 1992 |
| Hyundai Grandeur | 2 (LX) | 1992 – 1998 |
| Hyundai Sonata | 2 (Y2) | 1988 – 1991 |
| Hyundai Starex | 1 (A1) | 1997 – 2007 |
| Hyundai H-100 | – | – |
| Hyundai H-200 | – | – |
Reliability and structure of the G4CS engine
The top motor of the Hyundai Sirius family was launched in 1986 as an analog of the G4CP, but with a larger displacement. In practice, it is a typical 6-bolt Mitsubishi 4G64 in the first version. It has the same cast iron cylinder block (height 235 mm) with a cylinder diameter of 86.5 mm, a crankshaft with a piston stroke of 100 mm is installed inside it, connecting rods are 150 mm long, piston height is 35 mm. As a result, it allowed to get 2.351 liters of volume or simpler 2.4 liters.
The block is fitted with an 8-valve single-shaft SOHC head, the same as on the 4G64. There are hydrocompensators and belt drive timing, which is desirable to change every 60 thousand kilometers. It is not necessary to adjust the valves.
You can distinguish G4CS and 6-bolt 4G64 by the valve cover. Otherwise, it is the same Japanese assembled by Koreans.
Since this motor is a part of the Sirius family, here are some very close to it models: 1.6 G4CR, 1.8 G4CN and G4CM, 2.0 G4CP.
This is a typical grassroots motor that was put mostly in vans and other large cars. Since 2000, Hyundai began to produce a more modern modification – G4JS, but this 8-valve engine was put on different models for a long time.
Disadvantages, breakdowns and problems of the G4CS engine
- Low life of timing belts and balancers
Belts require frequent replacement. If they break, serious engine damage is possible. - Engine vibrations
Balancer shafts lead to vibrations, which accelerates the wear of the power unit supports. - Sensitivity to oil quality
The use of cheap lubricants negatively affects the resource of hydrocompensators. - Bursting exhaust manifold
At high mileage, a cracked exhaust manifold is common. The problem is usually solved by welding. - Floating RPMs
A dirty throttle plate or idle speed regulator (idle speed regulator) leads to unstable revs.
G4CS engine tuning
Atmo
In terms of atmospheric tuning, you’re not too lucky – this 8-valve cylinder head is no good and was not created for this purpose. Of course you can ignore it and give the camshaft to resharpening, put a straight exhaust, make a good intake, customize the ECU, but in the end it will cost more than the car itself, and the result will not be too impressive.
For power in your engine only the bottom has value, and the head is better to replace it with a 16-valve from 4G63, but it needs all the attachments, intake/exhaust, electronics and brain. And if we’re already swapping, then it’s wise to swap to a 4G63 turbo.
Disagree? Well, put it all in:
- atmospheric 4G63 head
- 272/272 camshafts with springs.
- 4G63T throttle plate.
- cold intake
- fuel rail from Galant
- 450 cc injectors
- large capacity fuel pump
- 4-2-1 spider
- exhaust on 60-65 mm pipe
Tune it all up and it will all drive tolerably well, but certainly not like a turbo.
G4CS turbo
You can put a turbo directly on your SOHC head and standard piston if the motor is completely serviceable. To do this you need to buy this:
- turbo from Evolution with intercooler and piping
- fuel system from Evo
- enlarged radiator
- weld a turbo manifold
- build a good exhaust
All of this is assembled and tuned. Your motor without preparation should be able to handle +/- 300 hp.
The best way to do this is to replace the head with an Eva head:
- head on 4G63T + all attachments (which will increase the compression ratio to 11)
- forged pistons for low compression ratio
- install oil injectors in the block
- Walbro 255 pump
- 750cc injectors
- weld turbo manifold
- exhaust 76mm
Standard connecting rods are not bad and for 400 hp will fit (should and 500 hp to hold). Oil injectors do not burn, but still cut it is desirable, fuel from Evo is not enough for 400 hp, it is better to put 750cc injectors + more powerful pump. It is important to buy an exhaust from beginning to end on 76 mm pipe, so there will be no losses. Put it all in, tune and get your legal 400 hp on a standard TD05-16G turbo. It’ll be like a typical Evolution Stage 2.
You want more? Then you need stuff like this:
- large radiator
- large intercooler + thick 76mm piping
- a good intake manifold like AMS
- 272 camshafts with springs, plates and cut gears
- fuel ramp like Aeromotive
- 1000cc injectors
- pump 340 liters
- FP Green turbo or something close in size
- turbo manifold
You can get 500 hp on such a configuration, but it is better to replace the connecting rods with tuning ones.
High block allows you to put Evo crankshaft + connecting rods 156 mm and spin this motor further than standard 4G64. There are many options + ocean of tuning parts from Mitsubishi Evolution.
MOTOR RATING: 4+