Saab B202 Specifications
| Engine Model: Saab B202 |
| Engine Type: 4-cycle inline 4-cylinder DOHC 16-valve liquid-cooled gasoline |
| Total Displacement: 121.1 cu.in (1.98 L) |
| Rated Engine Power: 126-204 Hp (94-138 kW) at 5500 rpm |
| Fuel System Type: Electronic fuel injection |
____________________________________________________________________________________
The Saab B202 engine is a 2.0-liter, 16-valve, slanted
inline-four powerplant that belongs to the Saab H engine family. Introduced in
1984, it represented a milestone for Saab, featuring their first mass-produced
multi-valve cylinder head. The B202 was developed to replace the earlier B201
engine, bringing DOHC technology and improved volumetric efficiency to Saab's
performance-oriented lineup.
This engine family was engineered with a focus on durability, robust
construction, and the ability to withstand forced induction pressures that
defined Saab's turbocharged heritage. The B202's architecture, including its
cast-iron block and dual overhead camshafts, established a foundation for
reliability that enabled these engines to frequently exceed 300,000 km (186,000
mi) with proper maintenance.
The B202 engine is celebrated for its robust construction, distinctive slanted
installation, and the pioneering turbocharging technology that Saab championed.
Its cast-iron cylinder block provides exceptional rigidity for forced induction
applications, while the aluminum DOHC cylinder head with four valves per
cylinder improves breathing across the engine speed range. The Automatic
Performance Control (APC) system represented a significant innovation, allowing
the engine to adapt boost pressure based on fuel quality and knock conditions.
The engine family encompassed a range of outputs from naturally aspirated
variants through high-output turbocharged versions found in the SPG (Special
Performance Group) and Aero models. Maintenance considerations include the
timing chain system, which requires periodic tensioner inspection, and the
various fuel injection systems employed across the production run. The B202
remains highly regarded among enthusiasts for its combination of durability,
tunability, and the distinctive torque delivery characteristic of Saab's
turbocharged engines.
Engine Type: Inline 4-cylinder, 4-cycle, water-cooled gasoline engine.
Displacement: 1,985 cc (121.1 cu.in), equivalent to 2.0 L.
Valvetrain: DOHC, 16 valves (4 valves per cylinder) with hydraulic lifters.
Bore: 90.0 mm (3.54 in).
Stroke: 78.0 mm (3.07 in).
Firing Order: 1-3-4-2.
Engine Inclination: 45 degrees from vertical in the engine bay.
Naturally Aspirated Variant (B202i)
Compression Ratio: 10.1:1.
Maximum Power: 126-130 hp (94-97 kW, 128-132 PS) @ 6,000 rpm.
Maximum Torque: 170-173 Nm (125-128 lb-ft) @ 3,000 rpm.
Fuel System: Bosch LH-Jetronic 2.2 or 2.4.
Low-Pressure Turbo Variant (B202S / LPT)
Compression Ratio: 9.2:1.
Maximum Power: 141-145 hp (105-108 kW, 143-147 PS) @ 5,500 rpm.
Maximum Torque: 202 Nm (149 lb-ft) @ 3,000 rpm.
Fuel System: Bosch LH-Jetronic 2.4 or Lucas CU14.
Full-Pressure Turbo Variant (B202L / FPT)
Compression Ratio: 9.0:1.
Maximum Power: 160-175 hp (119-130 kW, 162-177 PS) @ 5,500 rpm.
Maximum Torque: 255-273 Nm (188-201 lb-ft) @ 3,000 rpm.
Fuel System: Bosch LH-Jetronic 2.2, 2.4, or Lucas CU14.
High-Output Turbo Variant (B202R / SPG /
Aero)
Compression Ratio: 9.0:1.
Maximum Power: 185-204 hp (138-152 kW, 188-207 PS).
Maximum Torque: 273-280 Nm (201-207 lb-ft) @ 3,000-3,500 rpm.
Fuel System: Bosch LH-Jetronic 2.4.2 or Saab Direct Ignition (DI).
The cylinder block is constructed from grey cast iron,
a material selected for its exceptional rigidity, vibration damping
characteristics, and resistance to the thermal and mechanical stresses generated
by turbocharged operation. The block features a closed-deck design with
reinforced cylinder walls to withstand elevated combustion pressures. The
deep-skirt configuration extends below the crankshaft centerline, providing
robust support for the five main bearings.
The block incorporates integrated oil galleries supplying the crankshaft main
bearings, connecting rod bearings, and the turbocharger in forced induction
variants. The cylinder bores are machined directly into the cast iron without
separate liners, providing a durable running surface. The block's inclined
mounting angle of 45 degrees was designed to lower the vehicle's center of
gravity and improve weight distribution.
The cylinder head is manufactured from aluminum alloy
and houses the DOHC arrangement with four valves per cylinder. This was Saab's
first mass-produced 16-valve cylinder head, representing a significant
advancement over the previous 8-valve designs. The pent-roof combustion chambers
are optimized for efficient flame propagation and high compression ratios.
Intake valves measure 35.0 mm (1.38 in) in diameter, while exhaust valves
measure 31.0 mm (1.22 in).
The valvetrain utilizes hydraulic lifters (lash adjusters) integrated into the
bucket tappets, eliminating the need for manual valve clearance adjustments. The
dual camshafts are driven by a double-row timing chain, a design chosen for
enhanced durability and extended service intervals. The intake camshaft
incorporates a provision for driving the distributor in models equipped with
conventional ignition systems.
The fuel system configuration varies across the B202
production run. Naturally aspirated variants utilize Bosch LH-Jetronic 2.2 or
2.4 fuel injection, an air-flow meter-based system that measures intake air
volume to determine fuel delivery. Turbocharged variants employ either Bosch
LH-Jetronic 2.4 or 2.4.2 systems, often integrated with the APC boost control
system.
Late-production high-output variants in the Saab 9000 utilized the Saab Direct
Ignition (DI) system with integrated ignition and fuel management. Lucas CU14
fuel injection systems were used on certain variants for specific markets. The
intake manifold is constructed from aluminum and features runner lengths
optimized for torque production. A return-type fuel system maintains pressure at
the fuel rail, with a pressure regulator mounted on the rail.
The lubrication system is a forced-feed, wet-sump type
utilizing a rotor-type oil pump mounted to the front of the crankshaft. The pump
is driven directly by the crankshaft, ensuring immediate oil pressure upon
startup. Oil is drawn from a stamped steel oil pan through a baffled strainer
before pressurization. A full-flow spin-on oil filter is mounted externally on
the cylinder block.
The system supplies lubricant to the crankshaft main bearings, connecting rod
bearings, camshaft bearings, hydraulic lifters, and timing chain tensioner. In
turbocharged variants, an additional oil feed line supplies the turbocharger
center bearing, with a return line draining oil back to the sump. An oil cooler
is incorporated on high-output turbocharged variants to maintain oil temperature
under sustained high-load operation.
The cooling system is a pressurized, water-cooled setup
utilizing a centrifugal water pump driven by the engine’s accessory belt. A
wax-type thermostat with a rated opening temperature of 87°C (189°F) regulates
the engine operating temperature. Coolant circulates through the cast-iron
cylinder block and aluminum cylinder head before passing through a cross-flow
radiator.
In turbocharged variants, an additional coolant circuit serves the turbocharger
bearing housing, providing cooling after engine shutdown to prevent oil coking.
An electric cooling fan, controlled by a thermoswitch or the engine control
unit, provides supplemental airflow across the radiator when required. The
expansion tank is pressurized and incorporates a pressure cap rated for 1.0-1.2
bar (14.5-17.4 psi).
Early turbocharged variants utilize a Garrett T3
turbocharger. Units produced before 1988 feature oil-cooled bearing housings;
units after 1988 incorporate water-cooled bearing housings for improved
durability. Later performance variants, including the B202R, employ a Mitsubishi
TE-05 turbocharger with a smaller turbine housing for reduced lag and improved
transient response. The APC system controls boost pressure via a solenoid valve
that regulates wastegate actuation based on knock sensor input.
Most B202 engines utilize a distributor-based ignition
system with electronic advance control. The distributor is driven by the intake
camshaft and is mounted at the rear of the cylinder head in the Saab 900 and at
the front in the Saab 9000. Late-production Saab 9000 models with the B202R
feature the Saab Direct Ignition (DI) system, a cassette-style system with
individual ignition coils mounted over each spark plug, eliminating the
distributor.
Timing System: The camshafts are driven by a double-row
timing chain. The system consists of a single chain connecting the crankshaft
sprocket to the intake and exhaust camshaft sprockets. A hydraulic chain
tensioner, supplied with oil pressure from the lubrication system, maintains
consistent chain tension throughout the engine’s operational life. The
double-row chain design provides increased safety margin over single-chain
configurations.
APC (Automatic Performance Control): This pioneering system monitors engine
knock through a piezoelectric sensor mounted on the cylinder block. The APC unit
adjusts boost pressure by modulating the wastegate control valve, allowing the
engine to operate on fuel octane ratings ranging from 91 to 98 RON. The system
provides higher boost when fuel quality permits and reduces boost to prevent
knock when lower-octane fuel is detected.
Exhaust System: The exhaust system incorporates a cast-iron manifold, with
turbocharged variants featuring a turbocharger mounted directly to the manifold
flange. A catalytic converter is present on all variants meeting market-specific
emissions regulations. The system includes an oxygen sensor for closed-loop fuel
control in fuel-injected variants.
Overall Engine Length: 620 mm (24.41 in).
Overall Engine Width: 590 mm (23.23 in).
Overall Engine Height: 680 mm (26.77 in).
Dry Weight: The complete engine assembly weighs
145 kg (320 lb) for naturally aspirated variants and 155 kg (342 lb) for
turbocharged variants, inclusive of the turbocharger, intake manifold,
and ancillary components.
Engine Oil Capacity (with Filter): 4.0-4.3 liters
(4.2-4.5 qt), depending on oil cooler configuration. Engine Oil Specification:
SAE 10W-40 or 5W-40 meeting API SG or higher classification. Turbocharged
variants require higher-quality oils meeting API SJ or higher. Coolant Capacity:
7.0-8.0 liters (7.4-8.5 qt) inclusive of the radiator and heater circuit,
varying with turbocharger cooling circuit. Fuel Filter Replacement Interval:
40,000 km (25,000 mi).
Spark Plug Type: NGK BPR7ES or equivalent for turbocharged variants; NGK BPR6ES
for naturally aspirated variants. Spark Plug Gap: 0.7-0.8 mm (0.028-0.031 in)
for turbocharged variants; 0.8-0.9 mm (0.031-0.035 in) for naturally aspirated
variants. Spark Plug Replacement Interval: 30,000 km (18,600 mi). Valve
Clearance: Hydraulic lifters automatically maintain clearance; no manual
adjustment is required. Lifter noise may indicate oil supply issues or component
wear.
Timing Chain Inspection: Inspection of the timing chain tensioner and chain
guide wear is recommended at 100,000 km (62,000 mi). Chain stretch is uncommon
due to the double-row design. Timing Chain Tensioner Replacement: The hydraulic
tensioner may require replacement if chain rattle is evident at startup,
particularly in higher-mileage engines. APC System Inspection: The knock sensor
and boost control solenoid should be inspected if performance degradation or
incorrect boost levels are observed.
Cylinder Head Bolts, Step 1: 40.0 Nm (4.1 kgf-m, 30
lb-ft).
Cylinder Head Bolts, Step 2: 80.0 Nm (8.2 kgf-m, 59 lb-ft).
Main Bearing Cap Bolts: 80.0 Nm (8.2 kgf-m, 59 lb-ft).
Connecting Rod Cap Bolts: 50.0 Nm (5.1 kgf-m, 37 lb-ft).
Camshaft Bearing Cap Bolts: 20.0 Nm (2.0 kgf-m, 15 lb-ft).
Intake Manifold Bolts: 20.0-25.0 Nm (2.0-2.5 kgf-m, 15-18 lb-ft).
Exhaust Manifold Nuts: 25.0-30.0 Nm (2.5-3.1 kgf-m, 18-22 lb-ft).
Crankshaft Pulley Bolt: 120.0-140.0 Nm (12.2-14.3 kgf-m, 89-103 lb-ft).
Spark Plugs: 25.0-30.0 Nm (2.5-3.1 kgf-m, 18-22 lb-ft).
Oil Filter (Spin-on Type): 15.0-20.0 Nm (1.5-2.0 kgf-m, 11-15 lb-ft).
Turbocharger Mounting Nuts: 35.0-40.0 Nm (3.6-4.1 kgf-m, 26-30 lb-ft).
Flywheel / Drive Plate Bolts: 60.0-70.0 Nm (6.1-7.1 kgf-m, 44-52 lb-ft).
Timing Chain Tensioner Bolt: 70.0 Nm (7.1 kgf-m, 52 lb-ft).
The Saab B202 engine was utilized across the Saab
product lineup from 1984 through 1993, with some variants extending into 1994
for certain markets.
Saab 900 (Classic, Type 900)
1984-1993: B202i in naturally aspirated 900 models.
1984-1993: B202L in 900 Turbo models across various output levels.
1990-1993: B202S in low-pressure turbo 900 models.
1985-1991: B202R in Special Performance Group (SPG) and Carlsson trim levels in
select markets.
Saab 9000 (Type 9000)
1985-1989: B202i in naturally aspirated 9000 models.
1985-1993: B202L in 9000 Turbo models.
1990-1993: B202S in 9000 low-pressure turbo models.
1988-1993: B202R in 9000 Aero, Talladega, and Carlsson performance variants,
including the high-output versions with Saab Direct Ignition in later
production.
____________________________________________________________________________________
| Car Engines Technical Specifications |
| Small Engines Technical Specifications |
| Industrial Engines Technical Specifications |
| Outboard Engines Technical Specifications |
