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.
Turbocharged engines used Garrett T25 turbochargers and the B234R (9000 Aero manual) used a Mitsubishi Heavy Industries TD04HL-15G-6 in model year -93 and TD04HL-15T-6 later on.
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.
| 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) |
Note: The primary difference between the B204L and the B204R is with the intercooler, the wastegate 'base boost' setting.
Read more about this topic: Saab H Engine