Turbo Legacy info
Posted: Wed Sep 07, 2005 4:34 am
Was going through some files and stumbled across this....I saved it from some where.
Full Text COPYRIGHT Chilton Co. 1990
CUT-RATE AUDI
Saying 'Subaru' before 'sport sedan' is no longer a non sequitur now that the
company has introduced the Legacy Sport Sedan.
Like its brothers, the LSS's turbo-charged 2.2 L flat four uses a die-cast
aluminum crankcase with cast-in iron cylinder liners. To enchance rigidity,
Subaru engineers discarded the non-turbo's open deck cylinder design in favor
of a closed deck layout.
Coolant passages were also rerouted and enlarged, oil spray jets were tapped
into the main oil galley (they open at 57 [lb/in.sup.2]) and the main bearings
were modified to keep a higher volume of oil at the crankshaft. In addition,
a camshaft support was added to feed oil and coolant to the turbo, and the
pistons were given a dished crown (which lowers the compression ratio from
9.5:1 to 8.0:1), stronger rings, longer wrist pins and a molybdenum coating.
Company engineers retained the US Legacy's sohc four-valve head design
(Japanese cars get a dohc turbo 2.0 L) to keep weight and complexcity to a
minimum, while preserving low-end torque. They added more and larger coolant
passages on the intake side of the head, while changing the shape and spacing
of those on the exhaust side. Greater coolant flow was the result. And both
the head gasket and valve seat material have been strengthened to cope with
the increased stress.
The IHI turbochargers' wastegate is tied into the engine management system,
and limits boost to 8.7 [lb/in.sup.2]. Crankshaft and camshaft angle, spark
knock, throttle opening, vehicle speed, manifold pressure and exhaust content
are monitored. The crank and cam sensors are used to determine spark onset
and duration through the twin-coil ignition system. Sequential multi-point
fuel injection with larger injectors and a hot wire air flow meter are also
part of the turbo package.
To handle the increased thermal load, both the radiator and twin cooling fans
have been upsized. Subaru engineers also added a coolant expansion tank that
uses convection currents to cool the turbo after shut down. On the run, a
hood scoop feeds cool air to the turbo.
To handle the power (the turbo engine produces 160 hp @ 5600 rpm, and 181
lb/ft of torque @ 2800 rpm), both the five-speed manual and four-speed
automatic transmissions have been modified. All of the five-speed's gears
have been shot-peened, and the mainshaft bearings have been changed to a
'double-angular' design.
The gearbox case was also modified to accept a hydraulic clutch release fork,
shaft and cylinder because company engineers felt a cable-operated design's
pedal effort would be too high for this. (This change also prevented use of
Subaru's "hill-holder" feature.)
Also modified were the flywheel, pressure plate, clutch disk and pedal box.
However, the changes do nothing to help damp the low frequency vibration and
growl endemic to Subaru's flat engines, something the automatic accomplishes
with ease. Thus the five-speed's refinement levels are lower.
Beyond absorbing the flat-four's discordance, the 4EAT four-speed autmatic
transmission effectively masks the turbo engine's slight 'peakiness.' But
unlike other Japanese automatics, Subaru's system does away with 'power' and
'economy' buttons, and uses a logic circuit that chooses the correct setting
by how quickly the accelerator is depressed instead.
As is the Sport Sedan itself. Especially when fitted with the autmatic, it
acts like a less expensive -- and quicker -- Audi 90 Quattro. With 210 mm
(8.26 in.) of suspension travel, the sporty Legacy soaks up bumps with ease,
and leaves only the driver aware the Sport Sedan's speed. Even more proof
that the words 'Subaru' and 'sports sedan' do belong together.
-- End --
Full Text COPYRIGHT Chilton Co. 1990
CUT-RATE AUDI
Saying 'Subaru' before 'sport sedan' is no longer a non sequitur now that the
company has introduced the Legacy Sport Sedan.
Like its brothers, the LSS's turbo-charged 2.2 L flat four uses a die-cast
aluminum crankcase with cast-in iron cylinder liners. To enchance rigidity,
Subaru engineers discarded the non-turbo's open deck cylinder design in favor
of a closed deck layout.
Coolant passages were also rerouted and enlarged, oil spray jets were tapped
into the main oil galley (they open at 57 [lb/in.sup.2]) and the main bearings
were modified to keep a higher volume of oil at the crankshaft. In addition,
a camshaft support was added to feed oil and coolant to the turbo, and the
pistons were given a dished crown (which lowers the compression ratio from
9.5:1 to 8.0:1), stronger rings, longer wrist pins and a molybdenum coating.
Company engineers retained the US Legacy's sohc four-valve head design
(Japanese cars get a dohc turbo 2.0 L) to keep weight and complexcity to a
minimum, while preserving low-end torque. They added more and larger coolant
passages on the intake side of the head, while changing the shape and spacing
of those on the exhaust side. Greater coolant flow was the result. And both
the head gasket and valve seat material have been strengthened to cope with
the increased stress.
The IHI turbochargers' wastegate is tied into the engine management system,
and limits boost to 8.7 [lb/in.sup.2]. Crankshaft and camshaft angle, spark
knock, throttle opening, vehicle speed, manifold pressure and exhaust content
are monitored. The crank and cam sensors are used to determine spark onset
and duration through the twin-coil ignition system. Sequential multi-point
fuel injection with larger injectors and a hot wire air flow meter are also
part of the turbo package.
To handle the increased thermal load, both the radiator and twin cooling fans
have been upsized. Subaru engineers also added a coolant expansion tank that
uses convection currents to cool the turbo after shut down. On the run, a
hood scoop feeds cool air to the turbo.
To handle the power (the turbo engine produces 160 hp @ 5600 rpm, and 181
lb/ft of torque @ 2800 rpm), both the five-speed manual and four-speed
automatic transmissions have been modified. All of the five-speed's gears
have been shot-peened, and the mainshaft bearings have been changed to a
'double-angular' design.
The gearbox case was also modified to accept a hydraulic clutch release fork,
shaft and cylinder because company engineers felt a cable-operated design's
pedal effort would be too high for this. (This change also prevented use of
Subaru's "hill-holder" feature.)
Also modified were the flywheel, pressure plate, clutch disk and pedal box.
However, the changes do nothing to help damp the low frequency vibration and
growl endemic to Subaru's flat engines, something the automatic accomplishes
with ease. Thus the five-speed's refinement levels are lower.
Beyond absorbing the flat-four's discordance, the 4EAT four-speed autmatic
transmission effectively masks the turbo engine's slight 'peakiness.' But
unlike other Japanese automatics, Subaru's system does away with 'power' and
'economy' buttons, and uses a logic circuit that chooses the correct setting
by how quickly the accelerator is depressed instead.
As is the Sport Sedan itself. Especially when fitted with the autmatic, it
acts like a less expensive -- and quicker -- Audi 90 Quattro. With 210 mm
(8.26 in.) of suspension travel, the sporty Legacy soaks up bumps with ease,
and leaves only the driver aware the Sport Sedan's speed. Even more proof
that the words 'Subaru' and 'sports sedan' do belong together.
-- End --
