Saab H engine
The Saab H engine is a redesign of the Saab B engine, which in turn was based on the Triumph Slant-4 engine. Despite the name it is not an H engine or horizontally opposed engine, but a slanted inline-4. The H engine was introduced in 1981 in the Saab 900 and was also used in the Saab 99 from 1982 onwards and the Saab 90. It continued in use in the 900/9-3, 9000, and 9-5. The 2003 GM Epsilon-based 9-3 switched to the GM Ecotec engine, leaving the 9-5 as the sole user of the H engine. The last model year for this family of engines was 2009. The tooling and know-how was sold to BAIC.
All versions feature a grey cast iron block and an aluminum head with a single or double overhead chain driven camshafts. SOHC engines use two valves per cylinder and DOHC versions use four valves per cylinder with a pentroof chamber, the valve angle being 22 degrees from vertical. All engines use flat inverted bucket type valve lifters, hydraulic in the case of DOHC engines.
The engines were given numbers, for instance B201 is a 2.0 litre (20) engine with one camshaft.
B201 is the original H engine with two valves per cylinder and a single overhead camshaft. It was introduced in 1981 and unlike the B engine it did not have the central shaft which used to power the distributor, oil- and coolant pump. Instead the distributor is located at the front of the cylinder head and directly driven by the camshaft, while the integrated waterpump was replaced with a separate unit to the rear of the engine.
It was available with 100 PS (74 kW; 99 hp) at 5200 rpm using a single carburettor, 108 PS (79 kW; 107 hp) at 5200 rpm using a dual carburettor, 118 PS (87 kW; 116 hp) at 5500 rpm using Bosch K-Jetronic fuel injection and a turbocharged, fuel injected version with 145 PS (107 kW; 143 hp) at 5000 rpm. In 1986 an intercooled version of the turbo engine also became available, it produced 155 PS (114 kW; 153 hp) at 5500 rpm.
Valmet Automotive in Uusikaupunki planned also a downsized 1.6 liter version of B201 mainly due Finnish vehicle tax laws. Downsizing was made just with smaller cylinder bore. Prototype produced 92 hp at 5400 rpm with Bosch K-jetronic fuel injection. One prototype engine is displayed in Uusikaupunki Saab-museum.
B202 & B212
In 1984, Saab added a 16 valve cylinder head with double overhead camshafts. They retroactively renamed the 8-valve version the B201 and used B202 as the name of the new multi-valve unit. Another notable addition to the B202 was hydraulic valve lifters and Ecopower ("ep" in Italy, "(900)S" elsewhere), with a pre-heated catalytic converter for reduced emissions.
In 1991, Saab introduced a 140 bhp 2.1 litre normally aspirated 16 valve engine, with an increased displacement of (2119 cc/129 in³). The intake manifold was enlarged and redesigned for better and greater flow. The intake manifold and the head from the 2.1 liter constitute a well-known replacement for 1985-1993 16 valve 2.0 liter turbo cars. Power increase is modest at stock boost but becomes much more evident at higher boost levels.
B204 & B234
A major redesign of the H engine came in 1990 in the form of the new B234 for the Saab 9000. The B234 featured an increase in stroke from 78 mm (3.1 in) to 90 mm (3.5 in), increasing the displacement to 2.3 liters. With this increased stroke also came a new engine block with increased deck height to make sufficient room for the increased stroke length without being forced to use shorter connecting rods, and in-block counter-rotating balance shafts for reduced vibration (NVH). Unlike the previous B202, the block was no longer angled, but straight, something that made it unsuitable for the 900 model with its gearbox under the engine, built into the engine oil sump. The longer stroke B234 was last produced in 1998, that being the last year for the 9000 model. The B234 was selected as one of Ward's 10 Best Engines for 1995 and 1996.
The B202 was still being produced in 1993, but for the new generation Saab 900 being released in 1994 a new 2.0L engine was required. This new engine, the B204, was based on the 9000's B234, but in order to make the engine fit in the 900 the engine had to be shortened. This meant that a new chain drive for the camshafts was required to reduce the length of the engine. The B204 engine was available with natural aspiration in 900, 9000 and 9-3 in the form of 2.0i (B204i), with a low pressure turbo in the form of 9000 and 9-3 2.0t (B204E) or Saab 900 and 9-3 2.0T (B204L). B204R was briefly available in the 1999 9-3 Aero (U.S. market 'SE') model. B204 was in production in the Saab 9-3 until 2000, when it was replaced by B205.
With the introduction of the OBDII compliant B204 (also coincidental with the introduction of Trionic T5.5) Saab embarked on a new concept they termed as "EcoPower" where engines were designed for high power output while also delivering exceptional economy and low environmental impact.
The B204 and B234 are regarded by engine tuners as the preferable engine for performance tuning over the later B205 and B235 engines as the internals are of a higher strength. The later models had lightened internal components to improve efficiency and fuel economy but limit the total power output when the engine's software is revised to increase the boost pressures and specific power output. The B204 engine became a very popular engine swap for Vauxhall and Opel Astra, Calibra, Cavalier and Vectras with the GM T-body platform, in Scandinavia in the mid 2000s - the engine uses the same mounting positions due to sharing the same platform.
|Engine||Torque||Power||Compression ratio||Boost pressure|
|B204i:||177 N·m (131 lb·ft) @ 4300 rpm||130 hp (97 kW) @ 5500 rpm||10.1:1||-|
|B204E:||219 N·m (162 lb·ft) @ 3600 rpm||154 hp (115 kW) @ 5500 rpm||9.2:1||0.40 bar (5.8 psi)|
|B204L:||263 N·m (194 lb·ft) @ 2100 rpm||185 hp (138 kW) @ 5500 rpm||9.2:1||0.73 bar (10.6 psi)|
|B204R:||280 N·m (210 lb·ft) @ 2200 rpm||200 hp (150 kW) @ 5500 rpm||9.2:1||1.00 bar (14.5 psi)|
|B234i:||210 N·m (150 lb·ft) @ 4300 rpm||150 hp (110 kW) @ 5600 rpm||10.0:1||-|
|B234i:||210 N·m (150 lb·ft) @ 4300 rpm||150 hp (110 kW) @ 5600 rpm||10.5:1||-|
|B234E:||260 N·m (190 lb·ft) @ 2100 rpm||170 hp (130 kW) @ 5700 rpm||9.25:1||0.55 bar (8.0 psi)|
|B234L:||294 N·m (217 lb·ft) @ 1800 rpm||200 hp (150 kW) @ 5500 rpm||9.25:1||0.81 bar (11.7 psi)|
|B234R:||342 N·m (252 lb·ft) @ 1950 rpm||225 hp (168 kW) @ 5500 rpm||9.25:1||1.08 bar (15.7 psi)|
The B206 is a version of B204 but without the double balance shafts. It was only offered as a naturally aspirated engine B206I producing 133 hp (99 kW), seemingly a Europe-only option in 1994-1996 non turbo 900 NGs. This engine is popular among Saab tuners in Sweden (e.g. Trollspeed) due to the lack of balance shafts but with presumably equal strength as the turbo blocks with balance shafts.
B205 & B235
The B205 and B235 engines are an evolution of the B204 and B234 engines. They were introduced in the 1998 Saab 9-5 giving reduced fuel consumption and emissions with improved refinement. The changes included lightweight internal components (lighter valves, softer valve springs, longer conrods with lighter pistons, and balance shafts), lighter block and cover, heavier flywheel and more. Another development was the introduction of the Trionic 7 torque demand type engine management system. Trionic 7 equipped engines have the black direct ignition casing on top of the engine rather than the red of the Trionic 5.
Successor to the Saab H-Engine
The H-engine ended production with the 1st Generation Saab 9-5 in 2009 when the intellectual property was transferred to BAIC. Starting in 2003 with the 9-3 Sport Sedan, Saab began utilizing the General Motors Ecotec. Beginning in 2010 with the 2nd generation 9-5, all Saabs utilized the Ecotec. There were some technologies carried over into the Ecotec line from the Saab H-engine, but for the most part there is very little similarity between the two engine families. Saab continues to use its Trionic engine management system with the Ecotec.