GM Ecotec Engine: The L850 Four-Cylinder Family From the Gen I to Gen III

The GM Ecotec, also known by its codename L850, is a family of inline-four engines that GM built with displacements between 2.0 and 2.5 litres. The family replaced several older engines and was built in several plants, including facilities in Tennessee, Michigan and New York.

Where did the Ecotec name come from?

The Ecotec name was adopted in 1994 for a new generation of Family II engines, with the North American launch following in 2000. GM intended the Ecotec to become its global four-cylinder, and it had already fully replaced the company's OHV I4 line.

The name was not unique. It had already been used for the Opel Family II engine and the Family 1 and Family 0 ranges, and it was also applied to the Buick V6 when used in Holden vehicles. The Ecotec also covered the final DOHC derivatives of the earlier Family II, which had been substantially re-engineered for the new application.

Development began in 1994 with an international team of engineers from Opel's technical centre in Ruesselsheim, GM Powertrain in Pontiac, Michigan, and Saab in Sodertalje, Sweden. Much of the work was carried out by Lotus Engineering in Hethel, in the United Kingdom.

A four-cylinder that GM designed as a global family, built across three companies and then turbocharged, direct-injected and noise-engineered.

What was the basic Ecotec design?

The Ecotec is a DOHC four-valve design with a lost-foam cast aluminium block and head. The L850 was used for 86 mm bore applications, and the L880 for 88 mm bores, with displacements designed to run from 1.8 to 2.4 L. The engine uses aluminium pistons with cast iron cylinder liners, and twin balance shafts reduce vibration.

The first Gen I engine was the Ecotec 2.2 L61, introduced in May 1999. The current Ecotec line is built in Tonawanda, New York.

How did the LK9 and LSJ 2.0-litre engines work?

The LK9 is a turbocharged 2.0 L (1,998 cc) version of the L850 with an 86 mm bore. It uses an all-new reinforced sand-cast cylinder head, a five-bearing forged steel crankshaft, strengthened connecting rods and piston oil cooling jets. Its exhaust valves are sodium-cooled, and Saab's Trionic 8 management ran it. Saab knew the engine as the B207, and Opel as the Z20NET.

The LK9 produced 210 hp (157 kW) at 5300 rpm, and its torque of 221 lb ft (300 Nm) arrived at 2500 rpm. Boost peaked at 12.3 psi (0.85 bar), and the compression ratio was 9.5:1. Saab's direct ignition system was fitted, and a revised valvetrain and new timing chain completed the changes.

The LSJ was a supercharged LK9 with an Eaton M62 Roots-type supercharger and an air-to-liquid intercooler. It shares many parts with the LK9 and is rated at 205 hp (153 kW) at 5600 rpm, while torque is 200 lb ft (271 Nm) at 4400 rpm. Its redline is 6450 rpm. It was discontinued after 2007, when the Chevrolet Cobalt SS and Saturn Ion Red Line ended, and it appeared on Ward's 10 Best Engines list for 2006.

In late 2005 Brammo Motorsports made a deal with GM to use the supercharged 2.0 L in its Ariel Atom, where the engine was offered in ratings from 205 hp (153 kW) to 300 hp (224 kW).

What made the L61 2.2-litre smooth?

The L61 was designed for smoothness. Two balance shafts sat in the block, the power steering pump bolted to the cylinder head, and the water pump housing was cast into the block. The air-conditioning compressor and alternator were mounted directly to the block without brackets, and the engine did not use an EGR valve.

The L61 is 86 mm (3.4 in) in bore, with a 94.6 mm (3.72 in) stroke, a 9.5:1 or 10.0:1 compression ratio, and it measures 665 mm (26.2 in) long, 642 mm (25.3 in) wide and 655 mm (25.8 in) high. It weighs approximately 139 kg (306 lb). In North America it replaced the Quad-4 and GM 122 engines, first appearing in 2000 Saturn cars.

Several variants followed. The 2001 to 2003 Saturn L-Series had a more aggressive cam and a retune that trimmed power and added low-end torque. The 2002 Saturn VUE was the first North American L61 with electronic throttle control, and the 2004 Chevrolet Malibu used a version with a unitized exhaust manifold and catalytic converter. For 2007 an updated L61 based on the Gen II design arrived.

The supercharger and inlet manifold from the 2.0 LSJ can be bought as an official GM kit, and with modified engine control software they can turn the 2.2 into a supercharged version. The L61 also powered the Japanese-market Subaru Traviq, a badge-engineered Opel Zafira A, and it later went into the Fiat Croma unmodified and the Alfa Romeo 159 with gasoline direct injection.

What were the Z22YH and L42 variants?

The Z22YH was a direct-injection 2.2 L with a 12.0:1 compression ratio. It made 153 hp (114 kW) at 5600 rpm, and torque reached 162 lb ft (220 Nm) at 3800 rpm, and it appeared in the 2003 Opel and Vauxhall Vectra and Signum, the 2005 Zafira and the 2006 to 2009 Holden Astra in Australia and New Zealand.

The L42 was a compressed natural gas version of the 2.2, delivering 129 hp (96 kW) and 129 lb ft (175 Nm). It was used in the 2003 to 2004 Chevrolet Cavalier.

What was the turbo LNF engine?

The LNF was a turbocharged direct-injection 2.0 L (1,998 cc) introduced in the 2007 Pontiac Solstice GXP and Saturn Sky Red Line, with the engine mounted longitudinally. It had a square 86 mm (3.4 in) bore and stroke and a 9.2:1 compression ratio. Maximum boost reached 20 psi (1.4 bar), and it produced 260 hp (194 kW) at 5300 rpm and 260 lb ft (353 Nm) from 2500 to 5250 rpm, with a 6300 rpm redline.

Its sodium-filled exhaust valves borrowed technology from the Corvette V8. Injection pressure ran from 450 psi (31 bar) at idle to 2,250 psi (155 bar) at wide-open throttle. The Gen II block was similar to the 2.4 L and used variable valve timing, with bore walls strengthened for a weight increase of 2.5 lb (1.1 kg) and a coolant capacity 0.5 liters larger.

In December 2008 GM released a Turbo Upgrade Kit for the LNF, which raised power to 290 hp (216 kW) and torque to as much as 340 lb ft (461 Nm), depending on the model. The kit cost USD 650, included remapped calibration and upgraded MAP sensors, and raised boost from 18 to 21 psi (1.24 to 1.45 bar).

The LNF's distinctive features included a twin-scroll turbocharger, cam-driven high-pressure direct injection, continuously variable dual-camshaft valve timing, and sodium-filled stainless steel Inconel exhaust valves. It also had low-friction cast aluminium pistons with oil squirters, a forged steel crankshaft and connecting rods, a cast stainless steel exhaust manifold and a foam-cast Gen II block.

How did the LDK and LHU develop the turbo engine?

An updated LNF, the LDK, was released in 2008 to meet the Euro 5 standard. It kept the 9.2:1 compression ratio and was known as the A20NHT at GM Powertrain Europe. Its feature list closely matched the LNF, with the same twin-scroll turbo, direct injection, variable timing and Inconel exhaust valves.

The LHU added E85 flex-fuel capability to the LDK and was known as the A20NFT. It used a sand-cast Gen III block, larger Bosch injectors with ethanol-safe seals and a maximum engine speed of 6350 rpm. The A20NFT in the Opel Astra K TCR is a racing engine that swapped direct injection for multi-point injection.

What changed in the 2.2 Gen II and LAP engines?

In 2007 the L61 received many changes that originated in the LE5. It moved to the higher-strength Gen II block, a revised cylinder head with enlarged exhaust ports, and a camshaft with longer exhaust valve duration. Ignition changed from wasted spark to individual coil-on-plug, and an E37 controller with new crank and cam sensors replaced the old timing sensor. These changes raised power slightly and allowed the engine to meet PZEV standards, with a 10.0:1 compression ratio.

The LAP is a 2.2 L version on the Gen II block with cylinder head improvements from the 2.4 L LE5, dual variable valve timing, a 58X crank reluctor ring and digital crank and cam sensors. It keeps the 86 mm (3.4 in) bore and 94.6 mm (3.72 in) stroke of the L61, with 10.0:1 compression. The LE8 is an E85-compatible LAP that can run on regular unleaded or E85.

What was the 2.4-litre LE5?

The LE5 is a 2.4 L (2,384 cc) Ecotec with an 88 mm (3.5 in) bore and a 98 mm (3.9 in) stroke. Variable valve timing on the intake and exhaust improved low-end torque, and compression was 10.4:1. It made 164 to 177 hp (123 to 132 kW), with 159 to 170 lb ft (215 to 230 Nm) of torque, and it used a reinforced Gen II block with GKN-forged connecting rods. From July 2007 the rods were made of C70 powdered metal.

The LE5 went into the 2006 Buick LaCrosse built in Taiwan and Shanghai and the Buick GL8. It also powered the Polaris Slingshot, announced on 27 July 2014 with a five-speed manual and a final belt drive. The Slingshot is a three-wheeled side-by-side vehicle classed as a motorcycle.

The LAT was the LE5 used in GM's BAS mild-hybrid vehicles, while the LE9 was an E85-compatible version with the same 88 mm and 98 mm dimensions. The LAF was a direct-injected 2.4 L with 11.2:1 compression, slightly dished pistons and application-specific injectors. The LEA was its E85 variant, and the LUK added the eAssist mild-hybrid system. Both LAF and LUK had a maximum speed of 7000 rpm.

How did Gen III change the Ecotec?

The Gen III LCV is a 2.5 L (2,457 cc) engine with an 88.0 mm (3.46 in) bore, a 100.8 mm (3.97 in) stroke and 11.3:1 compression. It was first used in the 2013 Chevrolet Malibu and Cadillac ATS, and production began in April 2012 at GM's Tonawanda Engine plant. The block was reworked to reduce noise and vibration while improving fuel economy and low-end torque.

The LCV has dual overhead camshafts with continuously variable valve timing and a high-pressure returnless direct-injection system with a camshaft-driven pump. That pump supplies pressure from 750 psi (52 bar) at idle up to 2,250 psi (155 bar) at full load. The balance shafts moved to the oil pan module, and the engine cut noise intensity by 40 percent against the 2.4 L. Direct injection reduced emissions by 25 percent, and continuous cam phasing removed the need for EGR. Its redline is 7000 rpm.

The LKW shares the LCV's basic design but adds Intake Valve Lift Control, which gives two-stage variable lift of either 4.0 or 10.5 mm, and a start-stop system.

The Gen III LTG was a 2.0 L (1,998 cc) turbocharged direct-injection engine with an 86.0 mm (3.39 in) bore and stroke and 9.5:1 compression. It appeared in the 2013 Cadillac ATS and Chevrolet Malibu, and in the Cadillac XTS and XT5 for China. Its twin-scroll turbo, stainless exhaust manifold and rotacast aluminium head were designed to cope with turbine temperatures of 980 degrees Celsius (1,800 degrees Fahrenheit). Development was led by GMTCK, the GM Korea arm, and its redline is 7000 rpm.

The LSY succeeded the LTG in the 2019 Cadillac XT4 and CT6. It has an 83.0 mm (3.27 in) bore and 92.3 mm (3.63 in) stroke, and it adds Active Fuel Management and start-stop to favour fuel economy over performance. It is the standard engine option in China.

What was the HCCI Ecotec?

At Tech Show Torino in 2008, GM Powertrain Europe announced an ignition-less HCCI mode for the direct-injection 2.2 L. Homogeneous charge compression ignition uses a lean-burn cycle similar to a diesel's, and the version had two-step adjustable valve lift with variable cam phasing and cylinder pressure sensors. GM claimed a further fuel consumption reduction of 15 percent.

Ecotec engines at a glance