USDM or not ?
05 August 2012, 03:39 PM
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but there is no such Subaru term as USDM, there is a US model as EU and UK etc equally there are such models as STi7, 8, 9, 10, 11 and so on.
After STi6 JDM Subaru never number any other STis.
But "Dealers" and owners have used the STi7......etc etc to sell and differentiate them. Hence the names have stuck.
Likewise "People" have wrongly assumed because JDM that the USA was a USDM a but after years its stuck but doesn't make it right. but there again who cares
LOLIMHO IIRC
Tony
Last edited by T5NYW; 05 August 2012 at 03:40 PM.
05 August 2012, 03:43 PM
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USDM stands for U.S domestic market, as above not sure if its an official thing though..
A uk 02 wrx is an EUDM vehicle if i'm not mistaken.
The U.S 02 wrx came with smaller wheels, no 4pots etc.
A uk 02 wrx is an EUDM vehicle if i'm not mistaken.
The U.S 02 wrx came with smaller wheels, no 4pots etc.
Last edited by sunny1989; 05 August 2012 at 03:45 PM.
05 August 2012, 04:15 PM
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usdm = united states domestic market
edm = european domestic market
jdm = japanese domestic market
if its for the purpose of your flashing software uk = non usdm
edm = european domestic market
jdm = japanese domestic market
if its for the purpose of your flashing software uk = non usdm
Last edited by toneh; 05 August 2012 at 04:30 PM.
05 August 2012, 04:21 PM
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Interesting read
Two different versions of the 2.5-liter engine are used in the 2.5RS. Both use the same 99.5mm bore and 79.0mm stroke, resulting in a large (for a four-cylinder) 2,457 cubic centimeters. Power is rated at 165hp at 5,600rpm with torque weighing in at a meaty 162 lb/ft at 4,000rpm for the DOHC, and 166 lb/ft at 4,000rpm for the SOHC engine.
For 1998 model years, the existing DOHC engine used in the Legacy line, was put into service. It features four cams-two per bank-operating 16 valves. 1999 through 2001 models have what is referred to as Phase II engines, which feature a few internal changes aimed at solving durability issues, and of course different cylinder heads featuring single overhead cams per bank. These cylinder head changes were aimed at reducing friction, increasing economy, and improving torque.
Both engines use a die-cast aluminum block with cast in iron liners. The crankshaft literally fits between both halves of the engine, being supported by five large plain shell bearings that transmit forces horizontally into the block. Since horizontally opposed four-cylinder engines have such good inherent balance, the crankshaft webs are quite narrow, and have a fillet-style roll on their edges, increasing stiffness. DOHC engines featured the thrust bearing on the #3 main, while Phase II engines have it on the #5 main, aimed at reducing the tendency for deflection at elevated revs.
Connecting rods follow a standard H-beam pattern, with a thin inner web, and slim main caps. In an attempt to reduce friction, DOHC engines used a skirtless piston that literally has no skirt below the lower ring land. These engines have a tendency to produce piston slap, which can lead to broken lower ring lands. Phase II engines use a more conventional piston, featuring a full-length slipper skirt.
As mentioned before, the biggest changes came about in the area of cylinder heads. DOHC engines feature two cams per bank, operating directly on solid lifters. Phase II engines use a single cam per bank, operating two rocker arms per cylinder head. Y-shaped rocker arms operate the exhaust valves, while conventional finger arms operate the intake valves. Both engines use sixteen stainless steel valves, measuring 1.420 inches for intake and 1.240 inches for exhaust head diameters.
A tried-and-true pentroof combustion chamber is used, with a single center-mounted spark plug per cylinder. Compression is set at 9.7:1 on both engines, allowing the use of standard grade fuel.
Subaru made quite a few changes to the air metering system through the years. 1998 models use a hot wire mass air flow meter, while 1999 models use a hot film sensor. MAF sensors measure the density of the incoming air across the wire or film, and convert this into an electrical signal. From 2000 on, Subaru reverted to the manifold absolute pressure (MAP) system as used on the 2.2-liter engine. This system measures the air intake temperature and calculates the weight of air based off of volumetric efficiency maps stored in the management computer.
Both engines use a one-piece cast aluminum air intake plenum, featuring long runners for greater mid-range power. A 60mm throttle body is used on both engines, mounted directly aft of the intake plenum.
The exhaust system uses tubular steel header pipes, featuring a two-into-one design that merge into a somewhat strangled collector flange just before the first catalytic converter. Two oxygen sensors are used that work together to determine if the air-fuel mixture is consistent throughout the system. Exhaust tubing measures 2 inches in diameter and features a small resonator up front, with a large baffle-style muffler mounted at the rear of the car.
Putting that extra grunt down to the road, is Subaru's famous full-time all-wheel-drive system. Starting with either a 5-speed manual transmission or 4-speed automatic, Subaru uses a center differential for primary torque split. An open front differential is used on all models, with an open rear diff used through 1999, and a limited-slip rear diff on 2000 and later models. That rear differential is the venerable Hitachi R160, used for years in cars such as the Datsun 510.
The 5-speed transmission features dual cone synchronizers on second, third, and fourth gears, with a stronger mainshaft than 2.2-liter transmissions. A shorter throw shifter features a solid shaft for more positive engagement. Inside the bell housing, a 220mm clutch disc is hydraulically operated, and features a fluid damper between the master cylinder and operating cylinder for smoother operation.
On manual-equipped cars, the all-wheel-drive system uses a viscous coupling-type center differential, that splits torque 50/50, front to rear. As a wheel begins to slip, plates inside the viscous coupler begin to rotate at different speeds. This quickly shears, heats, and thickens the contained fluid in the coupler, causing power to be distributed to the other wheels.
On automatic-equipped machines, Subaru uses the 4EAT system, which normally runs in a 90/10 front to rear split. Since the 4EAT system runs in an "active" mode, the transmission's ECU will vary the torque split depending on what the car is doing at any given time. Torque can be sent to the rear under hard acceleration, or sent up front during heavy braking.
Underneath the front of every 2.5RS lie steel lower control arms, mounting to MacPherson struts. Manufactured by KYB, these struts are in fact the same as found on WRX Version III models sold in Europe and Japan, and feature a 22mm shaft mounted to rubber isolated upper strut bearings. Two mounting bolts locate the strut to a cast iron hub, with an eccentric "crash" bolt in the upper hole, used for camber adjustment.
In back, two lower parallel links and a trailing arm mount to a MacPherson strut. Again, rubber isolated strut bearings are used, and there is no provision for camber adjustment; but an eccentric mounting bolt is provided for adjusting rear toe.
Long travel coil springs have a linear spring rate of 159 pounds up front and 145 pounds in the rear. Both ends feature a closed coil, and use a thin rubber-isolating pad to reduce unwanted noise and vibration.
Solid anti-roll bars are used both fore and aft, measuring 19mm up front and 13mm in the rear. Center bushings feature a standard D-shaped rubber bushing. Drop links are manufactured out of a phenolic material and use rubber bushings with metal inserts.
Subaru uses a standard 5 x 100mm bolt pattern on every Impreza and Legacy, making wheel swaps easy between models. Subaru needed to specify a high 53mm offset to fill the wheel wells with 16-inch diameter, 7-inch wide rims. Early 5-spoke designs, as found on '98 and '99 model years weigh in at 17 pounds, while later 6-spoke designs weigh in half a pound less, at 16.5 pounds.
All 2.5RSs came equipped with V-rated 205/55-16 Bridgestone RE92 tires. Even though they feature a low 160-treadwear rating, RE92s have never received good marks for producing high levels of grip.
A vane-style power steering pump, which changes hydraulic pressure output based on engine speed, controls a rack and pinion featuring a slow 16.5 overall gear ratio. Although never heavy, an RS does require a good deal of wheel shuffling when navigating tight and twisty courses.
Large 10.7-inch diameter ventilated front brake rotors are clamped by twin-piston calipers. Single piston calipers work out back on 10.5-inch diameter solid rotors. Rubber flex hoses supply fluid, while a two-stage power booster supplies the assistance, producing a somewhat mushy feeling pedal. The four-channel anti-lock system features a convenient pull-able fuse for off-road events, as their bumpy nature can often confuse the system into pulling off all braking force.
Two different versions of the 2.5-liter engine are used in the 2.5RS. Both use the same 99.5mm bore and 79.0mm stroke, resulting in a large (for a four-cylinder) 2,457 cubic centimeters. Power is rated at 165hp at 5,600rpm with torque weighing in at a meaty 162 lb/ft at 4,000rpm for the DOHC, and 166 lb/ft at 4,000rpm for the SOHC engine.
For 1998 model years, the existing DOHC engine used in the Legacy line, was put into service. It features four cams-two per bank-operating 16 valves. 1999 through 2001 models have what is referred to as Phase II engines, which feature a few internal changes aimed at solving durability issues, and of course different cylinder heads featuring single overhead cams per bank. These cylinder head changes were aimed at reducing friction, increasing economy, and improving torque.
Both engines use a die-cast aluminum block with cast in iron liners. The crankshaft literally fits between both halves of the engine, being supported by five large plain shell bearings that transmit forces horizontally into the block. Since horizontally opposed four-cylinder engines have such good inherent balance, the crankshaft webs are quite narrow, and have a fillet-style roll on their edges, increasing stiffness. DOHC engines featured the thrust bearing on the #3 main, while Phase II engines have it on the #5 main, aimed at reducing the tendency for deflection at elevated revs.
Connecting rods follow a standard H-beam pattern, with a thin inner web, and slim main caps. In an attempt to reduce friction, DOHC engines used a skirtless piston that literally has no skirt below the lower ring land. These engines have a tendency to produce piston slap, which can lead to broken lower ring lands. Phase II engines use a more conventional piston, featuring a full-length slipper skirt.
As mentioned before, the biggest changes came about in the area of cylinder heads. DOHC engines feature two cams per bank, operating directly on solid lifters. Phase II engines use a single cam per bank, operating two rocker arms per cylinder head. Y-shaped rocker arms operate the exhaust valves, while conventional finger arms operate the intake valves. Both engines use sixteen stainless steel valves, measuring 1.420 inches for intake and 1.240 inches for exhaust head diameters.
A tried-and-true pentroof combustion chamber is used, with a single center-mounted spark plug per cylinder. Compression is set at 9.7:1 on both engines, allowing the use of standard grade fuel.
Subaru made quite a few changes to the air metering system through the years. 1998 models use a hot wire mass air flow meter, while 1999 models use a hot film sensor. MAF sensors measure the density of the incoming air across the wire or film, and convert this into an electrical signal. From 2000 on, Subaru reverted to the manifold absolute pressure (MAP) system as used on the 2.2-liter engine. This system measures the air intake temperature and calculates the weight of air based off of volumetric efficiency maps stored in the management computer.
Both engines use a one-piece cast aluminum air intake plenum, featuring long runners for greater mid-range power. A 60mm throttle body is used on both engines, mounted directly aft of the intake plenum.
The exhaust system uses tubular steel header pipes, featuring a two-into-one design that merge into a somewhat strangled collector flange just before the first catalytic converter. Two oxygen sensors are used that work together to determine if the air-fuel mixture is consistent throughout the system. Exhaust tubing measures 2 inches in diameter and features a small resonator up front, with a large baffle-style muffler mounted at the rear of the car.
Putting that extra grunt down to the road, is Subaru's famous full-time all-wheel-drive system. Starting with either a 5-speed manual transmission or 4-speed automatic, Subaru uses a center differential for primary torque split. An open front differential is used on all models, with an open rear diff used through 1999, and a limited-slip rear diff on 2000 and later models. That rear differential is the venerable Hitachi R160, used for years in cars such as the Datsun 510.
The 5-speed transmission features dual cone synchronizers on second, third, and fourth gears, with a stronger mainshaft than 2.2-liter transmissions. A shorter throw shifter features a solid shaft for more positive engagement. Inside the bell housing, a 220mm clutch disc is hydraulically operated, and features a fluid damper between the master cylinder and operating cylinder for smoother operation.
On manual-equipped cars, the all-wheel-drive system uses a viscous coupling-type center differential, that splits torque 50/50, front to rear. As a wheel begins to slip, plates inside the viscous coupler begin to rotate at different speeds. This quickly shears, heats, and thickens the contained fluid in the coupler, causing power to be distributed to the other wheels.
On automatic-equipped machines, Subaru uses the 4EAT system, which normally runs in a 90/10 front to rear split. Since the 4EAT system runs in an "active" mode, the transmission's ECU will vary the torque split depending on what the car is doing at any given time. Torque can be sent to the rear under hard acceleration, or sent up front during heavy braking.
Underneath the front of every 2.5RS lie steel lower control arms, mounting to MacPherson struts. Manufactured by KYB, these struts are in fact the same as found on WRX Version III models sold in Europe and Japan, and feature a 22mm shaft mounted to rubber isolated upper strut bearings. Two mounting bolts locate the strut to a cast iron hub, with an eccentric "crash" bolt in the upper hole, used for camber adjustment.
In back, two lower parallel links and a trailing arm mount to a MacPherson strut. Again, rubber isolated strut bearings are used, and there is no provision for camber adjustment; but an eccentric mounting bolt is provided for adjusting rear toe.
Long travel coil springs have a linear spring rate of 159 pounds up front and 145 pounds in the rear. Both ends feature a closed coil, and use a thin rubber-isolating pad to reduce unwanted noise and vibration.
Solid anti-roll bars are used both fore and aft, measuring 19mm up front and 13mm in the rear. Center bushings feature a standard D-shaped rubber bushing. Drop links are manufactured out of a phenolic material and use rubber bushings with metal inserts.
Subaru uses a standard 5 x 100mm bolt pattern on every Impreza and Legacy, making wheel swaps easy between models. Subaru needed to specify a high 53mm offset to fill the wheel wells with 16-inch diameter, 7-inch wide rims. Early 5-spoke designs, as found on '98 and '99 model years weigh in at 17 pounds, while later 6-spoke designs weigh in half a pound less, at 16.5 pounds.
All 2.5RSs came equipped with V-rated 205/55-16 Bridgestone RE92 tires. Even though they feature a low 160-treadwear rating, RE92s have never received good marks for producing high levels of grip.
A vane-style power steering pump, which changes hydraulic pressure output based on engine speed, controls a rack and pinion featuring a slow 16.5 overall gear ratio. Although never heavy, an RS does require a good deal of wheel shuffling when navigating tight and twisty courses.
Large 10.7-inch diameter ventilated front brake rotors are clamped by twin-piston calipers. Single piston calipers work out back on 10.5-inch diameter solid rotors. Rubber flex hoses supply fluid, while a two-stage power booster supplies the assistance, producing a somewhat mushy feeling pedal. The four-channel anti-lock system features a convenient pull-able fuse for off-road events, as their bumpy nature can often confuse the system into pulling off all braking force.
05 August 2012, 04:21 PM
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Interesting read
Two different versions of the 2.5-liter engine are used in the 2.5RS. Both use the same 99.5mm bore and 79.0mm stroke, resulting in a large (for a four-cylinder) 2,457 cubic centimeters. Power is rated at 165hp at 5,600rpm with torque weighing in at a meaty 162 lb/ft at 4,000rpm for the DOHC, and 166 lb/ft at 4,000rpm for the SOHC engine.
For 1998 model years, the existing DOHC engine used in the Legacy line, was put into service. It features four cams-two per bank-operating 16 valves. 1999 through 2001 models have what is referred to as Phase II engines, which feature a few internal changes aimed at solving durability issues, and of course different cylinder heads featuring single overhead cams per bank. These cylinder head changes were aimed at reducing friction, increasing economy, and improving torque.
Both engines use a die-cast aluminum block with cast in iron liners. The crankshaft literally fits between both halves of the engine, being supported by five large plain shell bearings that transmit forces horizontally into the block. Since horizontally opposed four-cylinder engines have such good inherent balance, the crankshaft webs are quite narrow, and have a fillet-style roll on their edges, increasing stiffness. DOHC engines featured the thrust bearing on the #3 main, while Phase II engines have it on the #5 main, aimed at reducing the tendency for deflection at elevated revs.
Connecting rods follow a standard H-beam pattern, with a thin inner web, and slim main caps. In an attempt to reduce friction, DOHC engines used a skirtless piston that literally has no skirt below the lower ring land. These engines have a tendency to produce piston slap, which can lead to broken lower ring lands. Phase II engines use a more conventional piston, featuring a full-length slipper skirt.
As mentioned before, the biggest changes came about in the area of cylinder heads. DOHC engines feature two cams per bank, operating directly on solid lifters. Phase II engines use a single cam per bank, operating two rocker arms per cylinder head. Y-shaped rocker arms operate the exhaust valves, while conventional finger arms operate the intake valves. Both engines use sixteen stainless steel valves, measuring 1.420 inches for intake and 1.240 inches for exhaust head diameters.
A tried-and-true pentroof combustion chamber is used, with a single center-mounted spark plug per cylinder. Compression is set at 9.7:1 on both engines, allowing the use of standard grade fuel.
Subaru made quite a few changes to the air metering system through the years. 1998 models use a hot wire mass air flow meter, while 1999 models use a hot film sensor. MAF sensors measure the density of the incoming air across the wire or film, and convert this into an electrical signal. From 2000 on, Subaru reverted to the manifold absolute pressure (MAP) system as used on the 2.2-liter engine. This system measures the air intake temperature and calculates the weight of air based off of volumetric efficiency maps stored in the management computer.
Both engines use a one-piece cast aluminum air intake plenum, featuring long runners for greater mid-range power. A 60mm throttle body is used on both engines, mounted directly aft of the intake plenum.
The exhaust system uses tubular steel header pipes, featuring a two-into-one design that merge into a somewhat strangled collector flange just before the first catalytic converter. Two oxygen sensors are used that work together to determine if the air-fuel mixture is consistent throughout the system. Exhaust tubing measures 2 inches in diameter and features a small resonator up front, with a large baffle-style muffler mounted at the rear of the car.
Putting that extra grunt down to the road, is Subaru's famous full-time all-wheel-drive system. Starting with either a 5-speed manual transmission or 4-speed automatic, Subaru uses a center differential for primary torque split. An open front differential is used on all models, with an open rear diff used through 1999, and a limited-slip rear diff on 2000 and later models. That rear differential is the venerable Hitachi R160, used for years in cars such as the Datsun 510.
The 5-speed transmission features dual cone synchronizers on second, third, and fourth gears, with a stronger mainshaft than 2.2-liter transmissions. A shorter throw shifter features a solid shaft for more positive engagement. Inside the bell housing, a 220mm clutch disc is hydraulically operated, and features a fluid damper between the master cylinder and operating cylinder for smoother operation.
On manual-equipped cars, the all-wheel-drive system uses a viscous coupling-type center differential, that splits torque 50/50, front to rear. As a wheel begins to slip, plates inside the viscous coupler begin to rotate at different speeds. This quickly shears, heats, and thickens the contained fluid in the coupler, causing power to be distributed to the other wheels.
On automatic-equipped machines, Subaru uses the 4EAT system, which normally runs in a 90/10 front to rear split. Since the 4EAT system runs in an "active" mode, the transmission's ECU will vary the torque split depending on what the car is doing at any given time. Torque can be sent to the rear under hard acceleration, or sent up front during heavy braking.
Underneath the front of every 2.5RS lie steel lower control arms, mounting to MacPherson struts. Manufactured by KYB, these struts are in fact the same as found on WRX Version III models sold in Europe and Japan, and feature a 22mm shaft mounted to rubber isolated upper strut bearings. Two mounting bolts locate the strut to a cast iron hub, with an eccentric "crash" bolt in the upper hole, used for camber adjustment.
In back, two lower parallel links and a trailing arm mount to a MacPherson strut. Again, rubber isolated strut bearings are used, and there is no provision for camber adjustment; but an eccentric mounting bolt is provided for adjusting rear toe.
Long travel coil springs have a linear spring rate of 159 pounds up front and 145 pounds in the rear. Both ends feature a closed coil, and use a thin rubber-isolating pad to reduce unwanted noise and vibration.
Solid anti-roll bars are used both fore and aft, measuring 19mm up front and 13mm in the rear. Center bushings feature a standard D-shaped rubber bushing. Drop links are manufactured out of a phenolic material and use rubber bushings with metal inserts.
Subaru uses a standard 5 x 100mm bolt pattern on every Impreza and Legacy, making wheel swaps easy between models. Subaru needed to specify a high 53mm offset to fill the wheel wells with 16-inch diameter, 7-inch wide rims. Early 5-spoke designs, as found on '98 and '99 model years weigh in at 17 pounds, while later 6-spoke designs weigh in half a pound less, at 16.5 pounds.
All 2.5RSs came equipped with V-rated 205/55-16 Bridgestone RE92 tires. Even though they feature a low 160-treadwear rating, RE92s have never received good marks for producing high levels of grip.
A vane-style power steering pump, which changes hydraulic pressure output based on engine speed, controls a rack and pinion featuring a slow 16.5 overall gear ratio. Although never heavy, an RS does require a good deal of wheel shuffling when navigating tight and twisty courses.
Large 10.7-inch diameter ventilated front brake rotors are clamped by twin-piston calipers. Single piston calipers work out back on 10.5-inch diameter solid rotors. Rubber flex hoses supply fluid, while a two-stage power booster supplies the assistance, producing a somewhat mushy feeling pedal. The four-channel anti-lock system features a convenient pull-able fuse for off-road events, as their bumpy nature can often confuse the system into pulling off all braking force.
Two different versions of the 2.5-liter engine are used in the 2.5RS. Both use the same 99.5mm bore and 79.0mm stroke, resulting in a large (for a four-cylinder) 2,457 cubic centimeters. Power is rated at 165hp at 5,600rpm with torque weighing in at a meaty 162 lb/ft at 4,000rpm for the DOHC, and 166 lb/ft at 4,000rpm for the SOHC engine.
For 1998 model years, the existing DOHC engine used in the Legacy line, was put into service. It features four cams-two per bank-operating 16 valves. 1999 through 2001 models have what is referred to as Phase II engines, which feature a few internal changes aimed at solving durability issues, and of course different cylinder heads featuring single overhead cams per bank. These cylinder head changes were aimed at reducing friction, increasing economy, and improving torque.
Both engines use a die-cast aluminum block with cast in iron liners. The crankshaft literally fits between both halves of the engine, being supported by five large plain shell bearings that transmit forces horizontally into the block. Since horizontally opposed four-cylinder engines have such good inherent balance, the crankshaft webs are quite narrow, and have a fillet-style roll on their edges, increasing stiffness. DOHC engines featured the thrust bearing on the #3 main, while Phase II engines have it on the #5 main, aimed at reducing the tendency for deflection at elevated revs.
Connecting rods follow a standard H-beam pattern, with a thin inner web, and slim main caps. In an attempt to reduce friction, DOHC engines used a skirtless piston that literally has no skirt below the lower ring land. These engines have a tendency to produce piston slap, which can lead to broken lower ring lands. Phase II engines use a more conventional piston, featuring a full-length slipper skirt.
As mentioned before, the biggest changes came about in the area of cylinder heads. DOHC engines feature two cams per bank, operating directly on solid lifters. Phase II engines use a single cam per bank, operating two rocker arms per cylinder head. Y-shaped rocker arms operate the exhaust valves, while conventional finger arms operate the intake valves. Both engines use sixteen stainless steel valves, measuring 1.420 inches for intake and 1.240 inches for exhaust head diameters.
A tried-and-true pentroof combustion chamber is used, with a single center-mounted spark plug per cylinder. Compression is set at 9.7:1 on both engines, allowing the use of standard grade fuel.
Subaru made quite a few changes to the air metering system through the years. 1998 models use a hot wire mass air flow meter, while 1999 models use a hot film sensor. MAF sensors measure the density of the incoming air across the wire or film, and convert this into an electrical signal. From 2000 on, Subaru reverted to the manifold absolute pressure (MAP) system as used on the 2.2-liter engine. This system measures the air intake temperature and calculates the weight of air based off of volumetric efficiency maps stored in the management computer.
Both engines use a one-piece cast aluminum air intake plenum, featuring long runners for greater mid-range power. A 60mm throttle body is used on both engines, mounted directly aft of the intake plenum.
The exhaust system uses tubular steel header pipes, featuring a two-into-one design that merge into a somewhat strangled collector flange just before the first catalytic converter. Two oxygen sensors are used that work together to determine if the air-fuel mixture is consistent throughout the system. Exhaust tubing measures 2 inches in diameter and features a small resonator up front, with a large baffle-style muffler mounted at the rear of the car.
Putting that extra grunt down to the road, is Subaru's famous full-time all-wheel-drive system. Starting with either a 5-speed manual transmission or 4-speed automatic, Subaru uses a center differential for primary torque split. An open front differential is used on all models, with an open rear diff used through 1999, and a limited-slip rear diff on 2000 and later models. That rear differential is the venerable Hitachi R160, used for years in cars such as the Datsun 510.
The 5-speed transmission features dual cone synchronizers on second, third, and fourth gears, with a stronger mainshaft than 2.2-liter transmissions. A shorter throw shifter features a solid shaft for more positive engagement. Inside the bell housing, a 220mm clutch disc is hydraulically operated, and features a fluid damper between the master cylinder and operating cylinder for smoother operation.
On manual-equipped cars, the all-wheel-drive system uses a viscous coupling-type center differential, that splits torque 50/50, front to rear. As a wheel begins to slip, plates inside the viscous coupler begin to rotate at different speeds. This quickly shears, heats, and thickens the contained fluid in the coupler, causing power to be distributed to the other wheels.
On automatic-equipped machines, Subaru uses the 4EAT system, which normally runs in a 90/10 front to rear split. Since the 4EAT system runs in an "active" mode, the transmission's ECU will vary the torque split depending on what the car is doing at any given time. Torque can be sent to the rear under hard acceleration, or sent up front during heavy braking.
Underneath the front of every 2.5RS lie steel lower control arms, mounting to MacPherson struts. Manufactured by KYB, these struts are in fact the same as found on WRX Version III models sold in Europe and Japan, and feature a 22mm shaft mounted to rubber isolated upper strut bearings. Two mounting bolts locate the strut to a cast iron hub, with an eccentric "crash" bolt in the upper hole, used for camber adjustment.
In back, two lower parallel links and a trailing arm mount to a MacPherson strut. Again, rubber isolated strut bearings are used, and there is no provision for camber adjustment; but an eccentric mounting bolt is provided for adjusting rear toe.
Long travel coil springs have a linear spring rate of 159 pounds up front and 145 pounds in the rear. Both ends feature a closed coil, and use a thin rubber-isolating pad to reduce unwanted noise and vibration.
Solid anti-roll bars are used both fore and aft, measuring 19mm up front and 13mm in the rear. Center bushings feature a standard D-shaped rubber bushing. Drop links are manufactured out of a phenolic material and use rubber bushings with metal inserts.
Subaru uses a standard 5 x 100mm bolt pattern on every Impreza and Legacy, making wheel swaps easy between models. Subaru needed to specify a high 53mm offset to fill the wheel wells with 16-inch diameter, 7-inch wide rims. Early 5-spoke designs, as found on '98 and '99 model years weigh in at 17 pounds, while later 6-spoke designs weigh in half a pound less, at 16.5 pounds.
All 2.5RSs came equipped with V-rated 205/55-16 Bridgestone RE92 tires. Even though they feature a low 160-treadwear rating, RE92s have never received good marks for producing high levels of grip.
A vane-style power steering pump, which changes hydraulic pressure output based on engine speed, controls a rack and pinion featuring a slow 16.5 overall gear ratio. Although never heavy, an RS does require a good deal of wheel shuffling when navigating tight and twisty courses.
Large 10.7-inch diameter ventilated front brake rotors are clamped by twin-piston calipers. Single piston calipers work out back on 10.5-inch diameter solid rotors. Rubber flex hoses supply fluid, while a two-stage power booster supplies the assistance, producing a somewhat mushy feeling pedal. The four-channel anti-lock system features a convenient pull-able fuse for off-road events, as their bumpy nature can often confuse the system into pulling off all braking force.
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05 August 2012, 04:52 PM
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Yeah i read it / flashed it first time on the usdm, then re flashed it on the bottom one the 2001 to 2005 wrx/sti just to make sure. It took the flash both ways anyway.
05 August 2012, 05:11 PM
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The term in japanese "Home" = 家庭の which translates into English as "Domestic" and for Subaru "JDM" = Japanese "Domestic" Market = Japanese "Home" Market
Japan can sell it's "home market" or ""Domestic market" but the USA, EU & AUS are definately not Subaru's or Japan's "home market" or ""Domestic market"
The reason for all this confusion is the Internet. All USA, UK AU forums have added "DM" on to the end of the designation code and now it's become the "Norm" except for the UK.
So Velly solly...IIRC according to Subau japan it's only "JDM", "UK", "EU" & "AU"
Japan can sell it's "home market" or ""Domestic market" but the USA, EU & AUS are definately not Subaru's or Japan's "home market" or ""Domestic market"
The reason for all this confusion is the Internet. All USA, UK AU forums have added "DM" on to the end of the designation code and now it's become the "Norm" except for the UK.
So Velly solly...IIRC according to Subau japan it's only "JDM", "UK", "EU" & "AU"
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