Evolution of the Liberty turbo

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Subaru MY04 Liberty GTThe Liberty is a mid-size car introduced by the Japanese manufacturer Subaru in February 1989 as a larger companion to the company's Leone/Loyale. Worldwide distribution started in 1990. In all other markets, the Liberty is called the Legacy but in Australia it is named the Liberty out of respect for Legacy Australia, an organization which aids veterans and their families during and after wars.

The worldwide introduction of the Liberty was a notable departure from Subaru products in the past. Subaru had earned a reputation of building vehicles that were regarded as "quirky" and other Asian manufacturers were bringing more upscale and conventional appearing models to the market. Unlike local cars in markets the Liberty was imported into, Subaru did't have a large displacement V6 or V8, instead offering only a boxer 4 cyclinder engine.

The largest sedan and wagon offered for sale by Subaru, the Liberty was more aerodynamic than previously built products, with soft edges and a more coherent appearance. The sedan had a break in the beltline where it dropped down from the windshield to the front door glass, and then jutted up from the rear door glass to the rear window, and the beltline was interrupted as it transitioned down to the rear window on the wagon. The beltline treatment was used again on the SVX when it was introduced in 1992.

The Liberty was interpreted by some as Subaru's attempt at participating in the growing, upscale market. The Liberty broke with many Subaru traditions, such as no longer locating the spare tire in the engine compartment, behind the engine and above the transmission. The Liberty was an all-new model, and positioned above the Leone in Subaru's model range. The Liberty also introduced an entirely new engine series, called the Subaru EJ engine, which was quieter and more powerful than the previous Subaru EA engine. The EJ engine is still in use in current models, 20 years after the first Liberty was produced.

Prior to the release of the first turbo-charged Liberty (Legacy) turbo, Subaru Australia had never enjoyed the experience of distributing a genuine performance car. Of course, there had been the 4WD turbo RX and Vortex, but neither could crack 10 seconds for the 0-100km/h sprint - although they were very reliable.

This article focuses and deals only with Australian delivered turbo Liberties.

 


Subaru Liberty RS

Liberty RS (1991-1994)

The RS was the gun version of the first Liberty series released, and arrived in Australia in late 1991 and became a hugely popular car until it was discontinued in 1994. The RS (Rally Sport) model was aimed squarely at world rallying, with many of its components and concepts carried over to the dominating Impreza WRX.

Set up as the high performance car in the Subaru line-up, the RS is quite firmly sprung in comparison to the naturally aspirated models. However, it does retain the hereditary suspension layout consisting of MacPherson struts at each corner, and front and rear sway bars (although all of these were higher-rate). Combined with the constant all-wheel-drive, the car is close to being completely foolproof in its handling. The rear differential uses a limited slip centre, the front diff is open, and there is also a front-to-rear LSD which varies its split depending on available grip. The large four wheel disc braking performance was okay back when the RS was released but the arrangement can give problems when the car is modified. Anti-lock brakes were an option on the RS and usually found on cars also fitted with a sunroof.

Liberty RS EJ20T EngineAvailable as either a sedan or wagon, the styling of the car is nothing too wild - a "Q-car" as it was often described. To avoid corrosion, 78% of the body weight was galvanised, while PVC, corrosion resistant wax and seals are used in other design areas. All RSs sport exclusive alloy wheels, bonnet scoop, driving lights, and black skirts all 'round.

The RS Liberty is powered by the first generation EJ20T engine, a 2,0L, quad-cam, 16-valve, intercooled turbo flat four with full engine management. Its basic design is very similar to today's WRX, however the RS uses slightly different cylinder heads and valvetrain, an 8.0:1 compression ratio, water-to-air intercooling and an IHI RHB52 turbo. Direct-fire ignition (ie a coil on top of each plug) is used. A total of 147kW was credited to the RS's engine at 6000rpm. Torque was also very strong for a two-litre with 260Nm at 3600rpm. However, there is a lack of turbo-assisted torque at low revs - around 3000-3500rpm is needed before any real boost pressure developed. All Australian-delivered Liberty RSs came with a 5-speed manual gearbox, while some other counties also saw the optional 4-speed auto version.

Liberty RS InteriorIn factory trim, the 1355kg RS sedan punches its way to 100km/h in 6.8 seconds and passes the quarter mile beams in 14.9 at 148.7km/h. Its top speed is still pretty quick today at  230km/h. Despite having 147kW, the car still returns around 11-12 litres/100km - and this improves to about 10 litres/100km with the fitment of a 3-inch exhaust and inlet mods.

Around corners, the RS displays minor understeer (an inherent trait of constant AWDs) which can develop into plough understeer if the driver is't careful to get the turn-in over early. Because the car has some turbo lag, the throttle should be squeezed prior to the apex and this will enable full-boost to blast the car out of the corner with total traction. Any understeer will be lost and the car becomes wonderfully neutral. It will only oversteer when being 'trail-braked' or when it is being driven on a loose surface.

Going quickly around corners in the wet is also one area that lets the Subaru's constant all-paw traction shine though - virtually any 2 wheel drive car will simply be left behind.

MRT Power Kits

MRT Power KitsLike so all other early Subaru turbo charged cars, the RS Liberty responds very well to the traditional turbo-car mods. A 3-inch exhaust from the turbo back comprising a high-flow cat, muffler and perhaps a central resonator will give the car about an extra 15% more power, and air intake modifications also reap good rewards. Boost also be increased to around 1 Bar (14.7psi) in a variety of ways, with the most common method being the use of a simple boost regulator, however we highly recommend the use of a good aftermartket ECU such as Link or Apexi Power PC.

There are no Power Kits for the RS Liberty, however MRT have done heaps of work on this model and are able to put together a package to suit your needs.

Download: Contact details regarding more info for the RS Liberty


Subaru Liberty B4

Liberty B4 (2001-2003)

After the success of the RS Liberty and despite the availability of a twin turbo charger GT version in Japan and Europe, no second generation turbo Liberty was imported into Australia. Instead, Australians had to wait until late until 2001 and the release of  the twin-turbo B4 based on the third generation Liberty.

Unlike all other Australia turbo Libertys, the B4 is powered by an EJ20B 69H engine - a turbocharged, intercooled, DOHC, 16-valve, 2-litre boxer four, which is of the same basic design as the engine found in the Liberty RS ten years previously. Internal developments resulted in reduced valvetrain mass and an increased compression ratio (up from 8.0 to 9.0:1), and Subaru endowed the B4 with two sequentially-staged turbos in order to maintain a good spread of torque. The Australian-delivered Impreza STis of the time used a single turbo and made more power than the Liberty - 206kW versus the B4's 190kW at 6400 rpm - but they did't offer 278Nm at a mere 2000 rpm or a 320Nm peak at 4800 rpm.

Liberty B4 twin-turbo engineThe primary turbocharger is arranged to quickly deliver boost up to 4000-4500 rpm, with the secondary turbocharger then kicking in to add flow in the higher ranges. to give a broad spread of power and torque, but with the Australian B4 it was never a perfect system. During the transitional phase - where the secondary turbocharger is starting to pump in addition to the primary unit - there's an ugly 'hole' in the torque delivery. It's enough for first-time passengers to ask if there's an engine problem.

Unfortunately for Subaru, the B4 is one of the worst tuned cars that was ever released. 98 octane fuel is a requirement, despite the fact that 98 octane fuel was especially difficult to come by at the time of release. The tune is also very lean and with excessive ignition advance across the rev range. This means the engine is often on the verge of detonation – as many owners can attest to. If ever there was a car that begged for enhancing, the B4 is it (see below).

Liberty B4 twin-turbo diagramDespite the engine flaws, there is a strong spread of torque and the B4 is a deceptively quick sprinter away from the lights with a full-on launch taking 6.5 seconds. These sorts of acceleration times can partly be attributed by the traction of Subaru's long-standing viscous AWD system. With drive taken by a relatively lightweight clutch and a nice short-shifting 5-speed 'box, the B4 apportions torque front-to-rear depending on the rotational speed difference between the front and rear wheels. Traction is also aided by a rear LSD.

Combining with AWD is the B4's lowered Bilstein struts, which offer an excellent combination of ride quality and handling. Despite being set up quite firmly, the car manages B-grade public roads without any nasty surprises - though small-amplitude, high-frequency bumps induces slight patter. This goes away at high speed, where the B4 shows itself as a truly wonderful machine. The well-weighted, precise steering allows you to place the chassis wherever you want and it wo't budge from that line. It just grips and grips and grips.

Liberty B4 InteriorIf you approach a corner a little hot in the B4, you can depend on its powerful ABS brakes to bring things back into line. The 294mm ventilated front discs are effectively pegged by twin-pot calipers, while the rears use 290mm ventilated discs and single-pot calipers. Aerodynamically, the Liberty feels stable - but not to the same degree as, say, an Evo, GT-R or even the STi Impreza.

Externally, the B4 is understated and similar in looks to the RX model. Carried over from the rest of Liberty line-up are side skirts, a rear spoiler and a fog light'd front bumper, with the only difference over the Liberty RX's panels is a small bonnet scoop, 17 x 7-inch forged alloy BBS wheels with 215/45 Bridgestone Potenza RE010s and the slight lowering of the Bilstein suspension.

Internally, the B4 pioneers a backlit instrument cluster and an awesome McIntosh single CD/tuner/cassette system and seven speakers with surprisingly good quality for an OE fitment giving a  full spectrum of sound and zero distortion. There is also a black leather Momo steering wheel, driver's seat 6-way electrice adjustment and standard leather trim.

MRT Power Kits

MRT Power KitsAs mentioned earlier, the Liberty B4 was delivered to Australia with a horrible tune that is very lean and with excessive ignition advance across the rev range and sports a huge power hole between 4000 and 4500rpm due to the transitional phase between the primary and secondary turbo-chargers. The good news is that the B4 comes with the ability to upgrade the factory ECU using EcuTeK software, negating the requirement to replace it with an aftermarket unit when chasing significant power increases. The ability to tune the factory ECU also allows direct access to factory calibration data, and the ability to use most of the default factory settings whilst just changing those required. If you own a B4, an EcuTeK upgrade is a must. Not only will it transform the power delivery of the car, but will also reduce detonation and significant increase engine safety.

Like the RS and other Subaru turbo models, the B4 also benefits greatly from a better flowing mandrel exhaust from the turbo back, larger intercooler and air intake modifications. Combined with an EcuTek upgrade, the B4 is absolutely trasnformed.

There are no Power Kits for the B4 Liberty, however MRT have done heaps of work on this model and are able to put together a package to suit your needs.

Download: Contact details regarding more info for the B4 Liberty


Subaru MY04 Liberty GT

Liberty GT 2L (2004-2005)

On May 23 2003, Fuji Heavy Industries debuted the redesigned fourth generation Liberty, known as the BL for sedan models and BP for wagons, and it was released worldwide in 2004. The large red plastic rear trim piece that first appeared in 1989, on both the sedan and wagon, with the word "Subaru" or "Liberty" had been removed. The Subaru star logo reappears on the back of sedans and wagons, now with a blue background. The fourth generation Liberty was presented the 2003-2004 Japan Car of the Year, Subaru's first win for the award.

The chassis was redesigned and made stiffer, and it marked the return of a turbocharged engine to the American market, featuring a 2.5 litre unit derived from that of the North American Impreza WRX STI. In Australia and Eurpoean markets, the twin-turbo was dropped from the lineup due to advancements in turbocharger technology and tightening emission standards and replaced with a single twin-scroll 2L engine.

The GT 5 speed manual engine power is line-ball with the superseded B4 with 190kw but torque increased slightly to 330Nm, but the auto version was slightly detuned to 180kw to preserve the gearbox. Whilst peak power remained similar to the B4, thankfully the driving characteristics of the GT is hugely improved thanks to the fitting of a single twin-scroll turbocharger instead of the previous twin-turbo system. Although slightly laggier at lower revs, the power hole between 4000-4500rpm was gone with the car pulling cleanly to 6400rpm before dropping off slightly to the 7500 limit.

Liberty GT InteriorIn addition to the revised turbo setup and drive-by-wire throttle, the 2004 Liberty GT was also the first locally delivered Subaru with variable valve timing on both inlet and exhaust camshafts. Only fitted to the inlet camshafts on the similar era MY03-on WRX and MY04-on Forester XT, the extra complexity of variable exhaust camshaft timing was primarily fitted to meet stricter emissions targets so the model could be sold in many markets including Europe. 

Like the B4, the GT comes with a 14 speaker McIntosh stereo system with an in-dash six CD that is arguably the best stereo in a sub $100K car that is designed by McIntosh for the Liberty with awesome response and minimal distortion. The GT also includes front, side and curtain airbags, stability control, power adjustable driver's seat with two memories, , leather upholstery, Data Dot security, self levelling bi-xenon headlights, sunroof, and dual zone automatic air.

The standard GT came with 17 inch alloys, whilst the Spec B gained 18 inch alloys, Bilstein suspension and alloy pedals.

Limited Editions

  • MY05 Liberty GT Tuned by STi2005 Subaru Liberty GT Tuned by STI - only 300 units produced. It featured an upgraded Electronic Control Unit (ECU) increasing peak power from 190 kilowatts to 200kW and torque from 330 Newton metres to 343Nm in the manual and 180kW to 190kW and torque from 310Nm to 343Nm in the automatic. This represents more than five per cent increase in power across both transmissions. Two STI twin tip sports mufflers complete the engine upgrade components, enhancing exhaust flow and providing better turbo response and a sportier sound.

    Suspension upgrades included STI lowered springs that drop the car by 15mm, sports tuned Bilstein front and rear struts, and a titanium look front strut brace increases the vehicle’s rigidity, enhancing handling and steering response. An STI rear lateral link set reduces suspension friction, improving ride, roadholding and steering precision as well.

    Customised body styling complements the vehicle’s performance capabilities and includes a front lip and rear boot spoiler enhancing vehicle aerodynamics by increasing down force and improving the front lift coefficient (CLf) by approximately 80%. Unique 18-inch wheels feature a wider 7.5-inch rim and Pirelli P Zero Rosso (215/45R18) tyres maximise grip, especially in wet conditions.

    Inside, an all-black interior features leather seats with STI embroidered alcantara inserts, complete with trademark red stitching, offering increased comfort levels. Titanium finish trim on the dash, centre console, door trim and an aluminium pedal set give the vehicle a modern, sporty edge. STI-red luminescent dash cluster lights complete the interior upgrades.

    The Liberty GT Tuned by STI is available as a sedan and wagon in both automatic and manual transmissions. The manual variant features a quick shift gear lever resulting in a quicker, more responsive and sporty gear change.

MRT Power Kits

Whilst the Liberty GT is much improved all round car compared to the previous B4, it still responds well to careful modifications that improve fuel economy, reliability and performance. Unlike other turbo-charged cars, simply placing large turbos and exhausts on the Liberty GT does't fit in with the understated image of the car.

MRT has done heaps of work on the Liberty GT and have designed three Power Kits for the GT in addition to custom work. All Power Kits use EcuTeK, giving the ability to tune the factory ECU whilst also allowing direct access to factory calibration data, and the ability to use most of the default factory settings whilst just changing those required.

MRT offers three Power Kits using EcuTeK:

MRT Power Kits

  • XA kit: Consists of an EcuTek upgrade for a guaranteed 13kw power increase and up to 15% torque increase over standard.
  • XB kit: Consists of an EcuTek upgrade, air intake modifications and upgraded top mount intercooler for a guaranteed 25kw power increase and up to 20% torque increase over standard.
  • XC kit: Consists of an EcuTek upgrade, air intake modifications, upgraded turbo, new custom dual exhaust, upgraded fuel pump and upgraded top mount intercooler for a guaranteed 65kw power increase and up to 70% torque increase over standard.

Download: Full Power Kit Details for the 2L Liberty GT


Subaru MY07 Liberty GT

Liberty GT 2.5L (2007-2008)

After being dropped from the product range in 2006 due to the inability of the EJ20T engine to meet stricter emissions control, 2007 saw the return of the Liberty GT to Australia now with the 2.5L turbo charged engine that had debuted in the US STi in 2003, then introduced in Australia with the Forester XT in 2003 and in the WRX in 2006. New new engine produced 184kw and torque increased to 339Nm and now ran on 95 octane premium fuel as opposed to the previous model's 180kW 2.0-litre turbo GT requiring 98 octane.

In Australia, the GT was offered in two main variants. The standard GT model came as a 5 speed shortshift auto only, and the Spec B GT came as a six speed manual with an auto option. The Spec B also came with 18 inch alloys, Bilstein shock absorbers and stronger front and rear differentials

Debuting in the 2004 GT was Subaru's new Intelligent Drive, or SI Drive, a new push button performance system for the electronic accelerator/engine and, in the GT, the automatic transmission, which allows the driver to change operating characteristics at the push of a button on the centre console.

MY07 Liberty GT Tuned by STiIn economy, or Intelligent mode, engine power and torque are reduced by approximately 20 per cent. In the auto, it also adjusts the shift timing. This can improve fuel economy by 10-20 per cent.

Sport mode is the default setting, which delivers full engine power. Sports Sharp mode, also available by flicking a button on the wheel, accesses a more responsive accelerator/engine map and a late upshift map for the automatic transmission, for maximum responsiveness and performance.

Like the previous 2L engine, the 2.5L GT included front, side and curtain airbags, stability control (not in the Spec B), power adjustable driver's seat with two memories, 14-speaker McIntosh sound with an in-dash six-stack CD player, leather upholstery, DataDot security, self-levelling bi-xenon headlights, sunroof and dual-zone automatic air-conditioning.

The 2007 model Liberty GT came with the larger 2.5 litre turbo engine and power increased to 184kW and torque up to 339Nm. A 6 speed manual gearbox also became avaialble in this model the the form of the Liberty GT spec.B. A tuned by STI model also became available with further upgrades including power stepping up to 194kW and torque up to a huge 350Nm. 

Limited Editions

  • STi twin exhausts2007 Subaru Liberty GT Tuned by STI - only 300 units. It featured an upgraded Electronic Control Unit (ECU) increasing peak power 194kw and 350Nm. Externally, the car also includes two STI twin tip sports mufflers, STI lowered springs that drop the car by 15mm, sports tuned Bilstein front and rear struts, and a titanium look front strut brace increases the vehicle’s rigidity, an STI rear lateral link set reduces suspension friction, 18 inch STi Enkei lightweight alloy wheels with Pirelli P-Zero Rosso tyres and  STi front spoiler. Inside, an all-black interior features leather seats with STI embroidered alcantara inserts complete with trademark red stitching, titanium finish trim on the dash, centre console, door trim, an aluminium pedal set, STI-red luminescent dash cluster lights and a gear box short shifter. Available as both a manual and auto.
     
  • 2008 Subaru Liberty GT Tuned by STI - only 300 units. Exactly the same as the 2007 version but with some additional colour options.

MRT Power Kits

Whilst the Evo IX is a wonderfully performing and handling car straight from the showroom floor, other markets such as the UK can access factory enhanced models such as the FQ-360 which Australia misses out on.

The good news is that MRT has done heaps of work on the Evolution IX, largely due to the MRT Evo IX development car that was used to design awesome Power Kits to give the Australian market similar packages to the FQ models available in the UK. All Power Kits use EcuTeK, giving the ability to tune the factory ECU whilst also allowing direct access to factory calibration data, and the ability to use most of the default factory settings whilst just changing those required.

MRT offers two Power Kits using EcuTeK.

MRT Power Kits

 
 
  • XA kit: Consists of an EcuTek upgrade for a guaranteed 15kw power increase and up to 15% torque increase over standard.
  • XB kit: Consists of an EcuTek upgrade and a custom dual exhaust for a guaranteed 25kw power increase and up to 25% torque increase over standard.
  • XC kit: Consists of an EcuTek upgrade, air intake modifications, upgraded turbo, new custom dual exhaust, upgraded fuel pump and upgraded top mount intercooler for a guaranteed 45kw power increase and up to 35% torque increase over standard.

Download: Full Power Kit Details for the 2.5L Liberty GT



Credits

Special thanks to AutoSpeed and Wikipedia for much of the content. Other sources include Cars Guide, Web Wombat and Drive.