The Hyundai Theta (G4KC) is a gasoline 4-cylinder automobile engine family. The third all-aluminum engine of Hyundai Motor Company debuted in the fourth-generation Hyundai Sonata sedan (codenamed NF), which was unveiled in August 2004 in South Korea. Hyundai Motor Manufacturing Alabama (HMMA) is currently building a Theta II engine shop on the grounds of their Montgomery, Alabama automobile factory. The shop will build only the Theta II engine for both the Hyundai plant and the new Kia Plant in West Point, GA. It was completed in August 2008.
Global Engine Alliance
The Global Engine Alliance was a joint venture between Chrysler, Mitsubishi Motors, and the Hyundai Motor Company for developing a line of shared 4-cylinder engines. The initial design of the engine block and cylinder head was handled by Hyundai. However, each manufacturer configured their variants of the initial design differently based on their needs. In 2009, Chrysler bought out Mitsubishi and Hyundai's stake in the joint-venture, however each company retained rights to build the engines.
The first version of the Theta Engine had two variants, the 2.0L and the 2.4L.
2.0L - G4KA
The 2.0L version is an Inline 4-cylinder engine that carries a bore and stroke of 86 mm and a 10.5:1 compression ratio; the engine makes 143 hp (107 kW; 145 PS) at 6,000 rpm and 140 lb·ft (190 N·m) of torque at 4,000 rpm. It uses a timing chain instead of belt, and the engine dry weight is 134 kg (295 lb).
2.4L - G4KC
The 2.4L version is an inline 4-cylinder engine that carries a bore of 88.0 mm, stroke of 97.0 mm and a 10.3:1 compression ratio; the engine makes 162 hp (121 kW; 164 PS) at 5,800 rpm and 164 lb·ft (222 N·m) of torque at 4,250 rpm.
2.0L - G4KD
The aluminum alloy engine block, which is formed using a high-pressure die-cast method, has a unique Metaldyne-supplied cassette-type balance shaft module with a two-stage oil pump built-in. In the lower-end, the block is reinforced by a ladder frame. Other notable features include fracture-split sinter-forged connecting rods manufactured by sinteron and a stainless-steel exhaust manifold.
Theta's EMS (engine management system) software is EMS-II from Siemens VDO and the 32-bit PCM (Powertrain Control Module) calculates the amount of intake air by utilizing a contamination-proof hot-film type MAF (mass air flow) sensor.
In the 2011 Hyundai Sonata and Kia Optima, this engine has Gasoline Direct Injection and produces between 198 hp (148 kW; 201 PS)-200 hp (149 kW; 203 PS) and 184 lb·ft (249 N·m) -186 lb·ft (252 N·m) of torque.
The MPI version of the 2.0L Theta engine has a 10.5:1 compression ratio, and it produces 163 hp (122 kW; 165 PS) at 6,200 rpm and 146 lb·ft (198 N·m) of torque at 4,600 rpm and is available in the Middle East.
The MPI version of the 2.4L Theta engine has a 10.5:1 compression ratio, and it produces 176 hp (131 kW; 178 PS) at 6,000 rpm and 168 lb·ft (228 N·m) of torque at 4,000 rpm and is available in the Middle East.
Theta/Theta-II Engine - 2.0L (1998cc)
(G4KA, G4KD, G4KF, G4KH,)
- Hyundai Genesis Coupe Port Injected 2.0 Turbocharged (2010-)
- Hyundai Sonata GDI 2.0 Turbocharged (2011-)
- Kia Rondo (2007-)
- Kia Forte 2.0 (2009-2013)
- Kia Optima GDI 2.0 Turbocharged (2011-)
- Kia Sportage GDI 2.0 Turbocharged (2011-)
- Hyundai ix35 MPI 2.0 (2010-)
- Hyundai Santa Fe (Sport Models) GDI 2.0 Turbocharged (2013-)
Theta/Theta-II Engine - 2.4L (2359cc)
(G4KC, G4KE, G4KG, G4KJ,)
- Hyundai Sonata (2006–2010)
- Hyundai Sonata GDI (2011-)
- Hyundai Sonata (2011-) (Middle East)
- Hyundai Tucson (2010-)
- Hyundai Santa Fe (2010-)
- Kia Optima (2006–2010)
- Kia Optima GDI (2011-)
- Kia Rondo (2007-)
- Kia Cadenza GDI (2011-)
- Kia Sportage (2011-)
- Kia Sorento (2011-)
- Kia Forte (2010-2013)
2.0T GDI turbo
The Theta engine is turbocharged for use in the Sonata 2.0T and Genesis Coupe. In this form it produces 210 hp (213 PS) @ 6,000 rpm on 87 octane (AKI) gasoline, and 223 hp (226 PS) on 93 AKI. Torque remains the same at 223 lb·ft (302 N·m) @ 2000 rpm. The Theta block used is very similar to the Mitsubishi Evolution X 4B11T, as core components like pistons and rods are said should move freely between them, however, the two engines are not identical. The 4B11T is a semi-closed deck block with larger oil and coolant passages, where as the Theta is an open deck block.
The turbo used is a Mitsubishi TD04 model. In stock trim this unit pushes a peak of approx. 16-18psi with a sustained 14psi.
The 2.0L GDI turbo in 2011 Sonata develops 274 hp (278 PS) and 269 lb·ft (365 N·m) of torque. The fuel economy is rated at 22mpg (10.7L / 100KM) in the city and 34mpg (6.92L / 100KM) on the highway. It comes exclusively with a 6-speed automatic transmission.
In 2013-11-05, Hyundai announced the creation of a new factory crate engine program at the 2013 SEMA Show in Las Vegas, which initially included a 2.0-liter, turbocharged 4-cylinder engine. The crate engine program began in December 2013.
- Chrysler World engine - Chrysler's GEMA built engines
- Mitsubishi 4B1 engine - Mitsubishi's GEMA built engines
- Aaron Robinson. "2010 Hyundai Genesis Coupe 2.0T Turbo". Car and Driver (May 2009).
- Hyundai launches crate engine program with 2.0L four and 3.8L V6
- Hyundai Motor Korea -- V6 3.0 Lambda Engine for 5G Grandeur - Korean link
- Hyundai Motor America Technician Internet Training -- Theta Engine(2.4L)
- SAE Technical Paper: New Energy Efficient Balance Shaft / Oil Pump Module for Hyundai NF