4eat

Subaru 4eat Solenoids
4eat Clutch Pack Replacement
4eat Transmission

Subaru motor vehicles have used manual, conventional automatic, and continuously variable (CVT) transmissions. Subaru manufactures its own manual and CVT transmissions (for non-Kei cars). Since the 1970s, all Subaru conventional automatic transmissions have been Jatco designs adapted to Subaru specifications.^{[citation needed]} Since the 2014 model year, the conventional automatic transmissions in North American-spec Subaru vehicles have been replaced with Lineartronic CVTs (with some exceptions such as Outbacks with the 3.6 liter engine).

The F-4EAT was a 4-speed, electronically controlled automatic transmission developed by Mazda and JATCO starting in 1990. It was also later produced by Ford Motor Company from 1991 to 2003, to replace the aging, 3-speed/hydraulic controlled ATX. 4Eat the (pregnancy experience headaches.' Glenville, expert 'To hours, grains, sugar For regular migraines that don't respond to regular painkillers, your doctor may prescribe a triptan, which narrows the blood vessels in the head and also blocks the transmission of. General Information. 4EAT stands for Four-Speed Electronic Automatic Transmission. This simply means that your vehicle is equipped with an automatic transmission with four gears. The gears for the 4EAT are as follows: Automatic transmission gear ratios for 2.5RS: 1st - 3.027.

Automatic[edit]

Three-speed[edit]

All of Subaru's three speed automatic transmissions were made by Jatco.

3AT[edit]

Gear Ratios: 1st 2.600 2nd 1.505 3rd 1.000 Rev 4.100
Usage: 1975–1979 Subaru Leone

3AT 1st revision[edit]

Gear Ratios: 1st 2.600 2nd 1.505 3rd 1.000 Rev 2.166
Usage: 1980–1982 Subaru Leone

3AT[edit]

The 3AT was a hydraulically controlled 3AT with available Single-Range 4WD.

Gear Ratios: 1st 2.821 2nd 1.559 3rd 1.000 Rev 2.257
Usage: 1983–1984,1990-1994 Subaru Leone 1985–1989 Subaru XT and Subaru BRAT

Four-speed[edit]

Subaru built their own four-speed automatic transmission based on the old Jatco design. It was available in FWD and Full-time awd.

ACT-4 or VTD[edit]

Subaru uses two types of traction delivery systems, called Active Torque Split, or the performance oriented Variable Torque Distribution, called VTD. Active Torque Split drives the front wheels directly and the rear wheels through a hydraulic clutch. The control unit monitors several factors including vehicle speed, gear position, and wheel speed and then varies the application of the clutch based on a model stored in memory. The effect is a constantly and actively changing torque to the rear wheels anywhere from a few percent to fully locked. The control unit can and does alter torque several times per second. Vehicles with higher power engines use a more aggressive model resulting in generally higher rear engagement. Later attempts at reducing customer confusion resulted in torque split numbers being given, but these have no meaning as there is no mechanical or other device to provide a static starting point for the control unit. This system is the more commonly used setup used on most Subaru products after its introduction on the XT6. VTD adds a twin planetary center differential to the clutch and therefore has a static, starting torque split calculated on the planetary gear ratio, with the most common being 45:55. The active clutch operation is similar to the ACT system, although the clutch is used to suppress differential action instead of as the differential itself. VTD was introduced on the Alcyone SVX in 1991 and is usually found in performance models equipped with a turbocharger, along with the VDC outback. Active Torque Split and VTD are found in both generations of the 4 speed while the 5 speed uses only VTD.

4EAT[edit]

This transmission was released in 1988 for use in the Subaru XT6 and Leone Touring Wagon. The bellhousing and input shaft were changed for the Subaru EJ engine, the first generation was used until about 1998, when a major redesign of the holding devices was released. The second generation saw use until 2008.

Gear Ratios: 1st 2.785 2nd 1.545 3rd 1.000 4th 0.694 Rev 2.272
Some versions had gear ratios of 1st 3.030 2nd 1.620 3rd 1.000 4th 0.694 Rev 2.272
Usage: 1988–1991 Subaru XT, 1990–2004 Subaru Legacy, 1992–1997 Subaru Alcyone SVX, and all Subarus 1995–2009

The Ford Motor Company also uses a transmission on some Ford, Kia Motors, Mercury, and Mazda products called the F-4EAT, which shares some similarities with the Subaru, since they are both manufactured by Jatco.^{[citation needed]} The Nissan Pathfinder has also used this transmission in the past with an external transfer case attached.

Five-speed[edit]

Subaru released the 5EAT w/ SportShift in 2003 based on the Jatco JR505 transmission.^{[citation needed]}

5EAT[edit]

Gear Ratios:

1st 3.5402nd 2.2643rd 1.4714th 1.0005th 0.834Rev 2.370

Usage: 2005+ Subaru Legacy and 3.0R; Subaru Outback XT, 3.0R, and 3.6R; Subaru Tribeca

Forester s-edition

Six-speed[edit]

Subaru made a one off paddle-shift AWD transmission for their B11S Concept car built off the 5EAT platform.

6EATT[edit]

Gear Ratios: 1st 3.636 2nd 2.264 3rd 1.471 4th 1.000 5th 0.834 6th 0.700 Rev 3.272
Usage: B11S Concept Car Only

A960E[edit]

Manufactured by Aisin/Toyota.

Gear Ratios:

1st 3.5382nd 2.0603rd 1.4044th 1.0005th 0.7136th 0.582Rev 3.168

Usage: 2012+ Subaru BRZ

Continuously variable[edit]

1989–1994 Subaru Justy ECVT/Justy 4WD ECVT[edit]

Subaru developed a CVT for the Subaru Justy to gain reasonable acceleration and fuel economy from its small three cylinder engine. It employs a push-belt system and comes with an optional 4WD unit that engages the rear wheels when a button on the shifter is depressed. It also has a 'sport mode' that when activated nearly doubles engine RPM for better torque distribution when towing or going uphill. The Shift Indicator reads P-R-N-D-Ds, Ds stands for Drive Sport, which doubles engine RPM. The CVT transmission proved unreliable after accumulating high mileage, causing Subaru to stop exporting cars with CVTs to North America until the fifth generation Legacy/Outback. Subaru did continue to build Kei cars with CVTs, only for sale in Japan. In addition to improving the design of the transmission over the years, Subaru has supplied other companies with CVTs, as well. The Justy ECVT was also available with hydraulically actuated 4WD (unlike the 5MT Justy, which has pneumatic actuation) in November 1988, this model was called the Justy 4WD ECVT.

Gear Ratios: Infinite
Usage: 1989–1994 Subaru Justy

Subaru Lineartronic CVT TR690 and TR580[edit]

Lineartronic CVT transmission

The fifth generation Legacy/Outback and the JDMSubaru Exiga received a newly revised CVT under the Lineartronic name. It is a metal chain, pulley-based CVT, which is considered the most reliable, due to the simplicity of the pulley system and durability of the metal chain. In addition, the metal chain pulley system is generally quieter than other CVT designs.

In the US, the Lineartronic is available with the 2.5i engine in the Outback, Legacy and Forester(2014), and the 2.0 FB engine in the Impreza and slightly modified for the XV Crosstrek. In SE Asia this transmission is also available for the 2.0i engine for the 2010 and later Legacy Legacy Asia spec. Subaru claims that the transmission provides 'uninterrupted power that maximizes fuel efficiency while keeping the engine at the optimal rev range'. EPA mileage estimates for the CVT with the 2.5i, naturally aspirated based engine, claim 30 MPG highway (29 Outback, 31 Legacy).^[1]

Lineartronic uses a specially modified torque converter to connect the engine to the transmission. It can slip like a traditional torque converter, but remains locked under all conditions except when coasting or traveling at very low speed. The persistent lockup condition under acceleration provides the efficiency and control of a clutch while still behaving much like a traditional planetary automatic transmission. The transmission can also be manually controlled by the driver by providing the ability to select 6 or 7 (if paired with a Diesel engine^[2]) or 8 different 'virtual' gears, where the transmission will hold a particular ratio.

Gear Ratios: 6.32:1
Usage: 2010–current Subaru Legacy / Outback / Exiga / Impreza / Levorg / Forester / XV and 2015 Subaru WRX Premium and Limited Editions.

TR580

2013-2020 Legacy/Outback 2.5L NA
2012-2020 Impreza 2.0L NA
2013-2020 Crosstrek 2.0L NA
2014-2020 Forester 2.5L NA

Maximum torque 250Nm

TR690

2010-2012 Legacy/Outback 2.5L NA
2015-2019 Legacy/Outback 3.6L NA
2014-2020 Forester 2.0L Turbo
2015-2020 WRX 2.0L Turbo
2019-2020 Ascent
2020 Legacy/Outback 2.4L Turbo

Maximum torque 400Nm

Manual[edit]

Four-speed[edit]

Subaru made several four speed transmissions from 1970–1989, they are listed below.

T71[edit]

Gear Ratios: 1st 3.307 2nd 1.944 3rd 1.344 4th 0.942 Rev 4.100
Usage: All 1970–1982 FWD

T71A 1st revision[edit]

Gear Ratios: 1st 3.636 2nd 1.950 3rd 1.193 4th 0.769 Rev 3.583
Usage: All 1983–1989 Subaru Leone FWD 1600cc

T71W 4WD[edit]

Gear Ratios: 1st 4.090 2nd 2.157 3rd 1.379 4th .971 Rev 4.100, Low Range 1.462
Usage: 1975–1980 Subaru Leone and 1978–1981 Subaru BRAT

T71W 4WD 1st revision[edit]

Gear Ratios: 1st 3.666 2nd 2.157 3rd 1.266 4th .885 Rev 4.100, Low Range 1.462
Usage: 1981 Subaru Leone 1600cc

T81W 4WD[edit]

Gear Ratios: 1st 3.636 2nd 1.950 3rd 1.266 4th .885 Rev 3.583, Low Range 1.462
Usage: 1981 Subaru Leone 1800cc

T81W 4WD 1st revision[edit]

Gear Ratios: 1st 3.636 2nd 1.950 3rd 1.193 4th .769 Rev 3.583, Low Range 1.462
Usage: 1982–1989 Subaru Leone 1800cc and 1982–1993 Subaru BRAT (EA-81 engine only)

Five-speed[edit]

T71G[edit]

Gear Ratios: 1st 3.666 2nd 2.157 3rd 1.266 4th .885 5th .725, Rev 4.100
Usage: 1975–1982 Subaru Leone

T71G[edit]

Gear Ratios: 1st 3.636 2nd 2.157 3rd 1.266 4th .885 5th .725, Rev 3.583
Usage: 1983–1989 Subaru Leone 1600cc

T81G[edit]

Gear Ratios: 1st 3.371 2nd 1.950 3rd 1.266 4th .885 5th .725, Rev 3.583
Usage: 1983–1989 Subaru Leone 1800cc (EA-81 Engine ONLY)!

5MT EA[edit]

1st 3.636 2nd 1.950 3rd 1.344 4th .971 5th .783, Rev 3.583

Usage: 1985–1994 Subaru Leone

5MT[edit]

This was the only five-speed 4WD transmission made for the Subaru Leone

Gear Ratios: 1st 3.545 2nd 1.947 3rd 1.366 4th .972 5th .780, Rev 3.416 Low Range 1.59
Usage: 1985–1994 Subaru Leone and 1985–1989 Subaru XT 1800cc

5MT full-time[edit]

This transmission was Subaru's first full-time 4WD transmission, only used in the Alcyone/XT6, and 3 door RX. In EU Leone turbo wagon.

Gear Ratios: 1st 3.545 2nd 2.111 3rd 1.448 4th 1.088 5th .871, Rev 3.416 Low Range 1.196
Usage: 1988–1991 Subaru XT-6

5MT Justy[edit]

The Justy used a transaxle, rather than a conventional Subaru transmission. This transmission was dropped in 1994 when you could only get a 4WD unit.

Gear Ratios: 1st 3.071 2nd 1.695 3rd 1.137 4th .823 5th .675, Rev 3.461 Final 4.437
Usage: 1984–1993 Subaru Justy

5MT Justy 4WD[edit]

After its introduction in 1984, the Justy was also available with 4WD and thus a different gearbox. The gear ratios for this gearbox were altered slightly. In 1994 the normal/FWD gearbox was dropped; one could only get a 4WD gearbox by then.

Gear ratios: 1st 3.071 2nd 1.695 3rd 1.137 4th .771 5th .631, Rev 3.461 Final 5.200
Usage: 1984–1994 Subaru Justy

5MT[edit]

It is notable to mention that only Turbo vehicles received a hydraulic clutch until 1995. Also, in 1998 Subaru changed from a push-style clutch to a pull-style, on turbo models, requiring minor bellhousing and fork changes.

Gear Ratios: 1st 3.785 2nd 1.945 3rd 1.500 4th 0.994 5th 0.780/(0.735 WRX) – Final 4.11 (3.90 WRX)
Usage: All 1990–2003 with EJ-Engine

MY 96-99 Transmission specs (and possibly other years)

Gear Ratios: 1st 3.545 2nd 2.111 3rd 1.448 4th 1.088 5th 0.825 (FWD) / 0.780 (AWD) / 0.871 (Outback AWD) --- Final 3.454 (FWD) / 3.900 (AWD) / 4.111 (Forester, Outback AWD)

Source: 1996 Subaru Legacy Service Manual/1999 Subaru Forester Service Manual

Also matches 1999 Legacy 30th Anniversary^[3]^[4]

5MT revised[edit]

Gear Ratios: 1st 3.454 2nd 2.062 3rd 1.448 4th 1.088 5th 0.871 Rev 3.545

Subaru 4eat Solenoids

different ratios for 2006-07

Usage: All 2003–2011 Subaru Non-Turbo

5MT revised 2012+[edit]

Gear Ratios: 1st 3.454 2nd 1.888 3rd 1.296 4th 0.972 5th 0.738 Rev 3.333 Final 4.111
Usage: All 2012-Present Subaru Non-Turbo

Six-speed[edit]

SJ Forester 2.5i[edit]

1st 3.4542nd 1.8883rd 1.2964th 0.9725th 0.7806th 0.695R 3.686Final 4.444:1^[5]

SJ Forester 2.5i, Impreza WRX STi and Legacy spec. B[edit]

There are several six speed manual transmissions currently available for USDM Subarus, found in the STi, Legacy Spec B, and 2015 WRX. The STi's 6MT has undergone various changes throughout the years, but have always had a limited slip front differential with Driver Controlled Center Differential (DCCD). In 2006, The STi's 6MT underwent some changes that included making the center differential a limited slip unit and a slight lengthening of some gears. The Spec. B's 6MT has different gear ratios (specifically 6th gear being longer) than the STi's unit, does not have DCCD, and neither the front nor center differentials are limited slip units. The Spec B's 6MT ratios are highly prized by some due to its longer ratios than those found in the WRX STi, while still retaining much of the STi unit's robustness.

Gear Ratios : 1st 3.636 2nd 2.375 (or 2.235) 3rd 1.761 (or 1.590) 4th 1.346 (or 1.137) 5th 0.971 (or 0.891) 6th 0.756 (or 0.707) Rev 3.545 (This only applies to either the 04-05 STi or the 06+ STi, not both, and not the Spec B.).
Usage: 2004+ Subaru WRX STi and 2005+ Subaru Legacy spec. B
Early 2004 WRX STi models came with axle stubs inserted in the transmission with female front axles. Late 2004 WRX STi models came without the stubs and instead had male front axles.
The 2004 and 2005 model WRX STi 6MT was a final drive of 3.90. In 2006 and 2007 the 6MT came with a final drive of 3.545 which made the 2006 and 2007 much sought after for the non-STi WRX owners as a transmission swap. This is due to the R160 rear differential 3.545 final drive of most of the non-STi WRXs.
Pre 2008 model year WRX STi 6MT versions utilizes a self-contained oil system with a trochoidal oil pump mounted in the rear of the transmission case. This capability was removed for 2008 and later years as Subaru elected to for a simplified splash/scraper lubrication system. However, the oil pump-equipped 6MT version is still listed as the transmission of choice in the STi Group N parts system, even for the 2015+ model year WRX STi, with the option of mounting a homologated transmission oil cooler. Subaru Tecnica International's choice to continue using the oil pump-equipped 6MT for Group N racing, originally for the 2007 model years and older, led to the assessment that oil pump transmissions are still favored for motorsport/heavy duty applications. As such, 2008+ WRX STi 6MT with the splash/scraper oil system is a byproduct of a cost-saving measure from Subaru, which may have determined an intricate lubrication system was not necessary for a showroom/production vehicle until it would be converted for motorsport use. ^[6]

Model	1st	2nd	3rd	4th	5th	6th	Reverse	Final Drive	DCCD	Front Diff	Center Diff	Rear Diff
Impreza WRX STi MY01-04 TY856WH3MA	3,636	2,375	1,761	1,346	0,971	0,756	3,545	3,900	35/65	A.P. Suretrac	Viscous Coupling (DCCD system MY03 onwards)	Viscous LSD
Impreza WRX STi MY01-04 TY856WH4MA	3,636	2,375	1,761	1,346	0,971	0,756	3,545	3,900	35/65	A.P. Suretrac	automatic electromechanical DCCD system	Viscous LSD
Impreza WRX STi MY05-07 TY856WW6MA	3,636	2,375	1,761	1,346	0,971	0,756	3,545	3,900	35/65	Helical LSD	automatic electromechanical DCCD system	Viscous LSD
WRX STi MY08-14 TY856UB1KA	3,636	2,235	1,590	1,137	0,891	0,707	3,545	3,900	41/59	Helical LSD	electronic (08-16 electromechanical) DCCD system	Torsen LSD
WRX STi MY15-18 TY856UW6AA	3,636	2,235	1,521	1,137	0,971	0,756	3,545	3,900	41/59	Helical LSD	electronic (08-16 electromechanical) DCCD system	Torsen LSD
WRX STi MY19-present TY856UW6AB	3,636	2,235	1,590	1,137	0,971	0,756	3,545	3,900	41/59	Helical LSD	electronic (08-16 electromechanical) DCCD system	Torsen LSD
SJ Forester 2.5i 2014-2018	3.454	1.888	1.296	0.972	0.780	0.695	3.686	4.444:1	50/50	viscous coupling	none	viscous coupling

BM/BR Legacy/Outback[edit]

The 2010-2014 Legacy and Outback models offer a six-speed manual as one of the two transmission options in the base 2.5i and 2.5i Premium and is the only option for the Legacy GT model. This transmission is an evolution of the 5MT split-case design, and does not share any parts with the STI's 6MT transmission. The transmission uses a cable shifter, unlike previous designs that use a direct mechanical linkage.

Legacy 2.5 GT Gear Ratios: 1st: 3.454, 2nd: 1.947, 3rd: 1.296, 4th: 0.972, 5th: 0.780, 6th: 0.666, Rev.: 3.636, Final Drive: 4.111
Legacy 2.5 NA Gear Ratios: 1st: 3.454, 2nd: 1.947, 3rd: 1.296, 4th: 0.972, 5th: 0.825, 6th: 0.695, Rev.: 3.636, Final Drive: 4.111
Outback 2.5 NA Gear Ratios: 1st: 3.454, 2nd: 1.947, 3rd: 1.296, 4th: 0.972, 5th: 0.825, 6th: 0.695, Rev.: 3.636, Final Drive: 4.444^[7]

2015 WRX[edit]

The 2015 WRX has a new 6-speed cable-shifted manual transmission behind the new FA20DIT boxer engine. This transmission uses a viscous limited slip center differential with a 50/50 torque split similar to the 5MT found in previous WRX's. Reverse is located to the right of 6th gear, and is accessed by lifting a lockout ring below the shift knob, similar to the STi 6MT.

Like the Legacy/Outback, the WRX 6MT is of a split-case design similar to the older 5MT and does not share any internal commonality with the WRX STi 6MT.

Gear Ratios are:1st: 3.4542nd: 1.9473rd: 1.2964th: 0.9725th: 0.7806th: 0.666Reverse: 3.636Final Drive: 4.111 (model TY751VB6CA) or 4.44

2018 Crosstrek[edit]

Gear Ratios are: 1st 3.8182nd 1.9473rd 1.2964th 1.0295th 0.8256th 0.738Final Drive 4.44:1

Notes[edit]

^http://www.subaru.com/engineering/transmission.html
^http://sgws.subaru.no/2015_outback_spesifikasjon.html?ref=1453239236.122
^'Subaru Transmission Chart'(PDF).
^'Relative measurement of 1999 Legacy Gear Ratios'.
^http://www.cars101.com/subaru/forester/forester2016.html
^https://www.sti.jp/en/competitor/n_parts/partslist.html
^'Transmission Chart'(PDF). Rallispec. Retrieved 15 June 2020.CS1 maint: discouraged parameter (link)

4eat Clutch Pack Replacement

Sources[edit]

'Subaru Transmission Specs'. Archived from the original on 1 August 2008.CS1 maint: discouraged parameter (link)
1977 Subaru Factory Service Manual
1983 Subaru Factory Service Manual
1984 Subaru Factory Service Manual
1979–2002 Subaru Owner's Manuals
'Rallispec LTD. – Subaru Gearbox Chart'. Sports Performance Drivers Association. Archived from the original on 24 February 2012. Retrieved 29 November 2009.CS1 maint: discouraged parameter (link)

(http://www.vdi-wissensforum.de. Enhanced performance of next generation LINEARTRONIC.

See also[edit]

Retrieved from 'https://en.wikipedia.org/w/index.php?title=List_of_Subaru_transmissions&oldid=1013544031'

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4EAT 101 “Best KeptSecret”

General Information

4EATstands for Four-Speed Electronic Automatic Transmission. This simplymeans that your vehicle is equipped with an automatic transmission withfour gears. The gears for the 4EAT are as follows:

Automatic transmission gear ratios for 2.5RS:

1st - 3.027

2nd - 1.619

3rd - 1.000

4th - 0.694

Reverse - 2.272

Final drive ratio - 4.44

Each gear can be taken tothe following MPH

1st-38

2nd-71

3rd-112

The4EAT is also equipped with the VTD (Variable Torque Distribution) AWDsystem. This AWD system adjusts power to wheels depending on drivingconditions, making it more technically advanced than the AWD systemused in manual-equipped vehicles. The normal driving split is 45% tothe front wheels and 55% to the rear wheels.

How does the 4EAT differfrom the 5MT? Is it better or worse for performance?

Thefirst difference between the 4EAT and 5MT is the AWD system. 5MT modelsuse a permanent 50/50 split between the front and rear wheels, whereasmodels equipped with the automatic make use of the technically superiorVTD system (mentioned above). The second difference is the gearing. The4EAT uses 4 gears to make use of its power, where 5MT models make useof 5 gears.

Froma stop: The 4EAT (stock) is much different performance-wise than the5MT. Models equipped with the 5MT are able to achieve theirpavement-rippling sub-six second 0-60 and low 14 second ¼ mile timesthanks to its ability to launch at 4000+ RPM. Models equipped with the4EAT must use the brake-torque technique (I also take no responsibilityfor potential damage caused to your car using this technique), however,stock 4EATs using this method can only launch at a maximum 3200 RPM,leading to a 0-60 time in the low 7 second range and a ¼ mile in themid-to-high 15 second range.

Froma roll: Judging from the very few 4EAT vs 5MT races that I havestudied, a 5MT will have about a 2 car lead on a similarly equipped4EAT in a race from 40 MPH to 100 MPH. Please note that in the fewdocumented races known, the 4EAT begins to trail after it shifts to 3rdgear, leading me to believe that the 4EAT’s major weakness are it’sgear ratios.

Stock5MT models dyno at around 170 WHP where 4EAT models dyno at around 150WHP. From my research, I have noticed about a 20-25 WHP differencebetween similarly equipped 4EAT and 5MT WRX’s due to the extradriveline loss through the torque converter.

What you need to make the4EAT comparable to a 5MT in acceleration and ¼ mile times.

Youneed a high stall torque converter. The main purpose of this mod is toraise the stall speed from 3200 RPM to around the 4200 RPM range;allowing the 4EAT to run 0-60 and quarter mile times consistent with5MT equipped vehicles. This mod is a MUST HAVE if youare planning on consistently drag racing your vehicle. The use of thismod for owners whom do not consistently drag race is debatable. Someargue that it increases daily drivability; others argue that it doesnot. You’ll have to decide.

I am not interested in 0-60or ¼ mile times, how else can I make my 4EAT a better daily driver?

Althoughthis is highly subjective, the general consensus is that the bestmethod to increase your 4EAT’s drivability is by installing anaftermarket header, uppipe and turbo back exhaust system . This willvirtually eliminate turbo-lag and give much better low and mid-rangepower. You can also add engine management to take full advantage ofyour modifications to further increase responsiveness and decrease lag.

Best First Mod for the 4EAT

Althoughthe idea of the best first mod is highly subjective, I, along with manyothers, feel that an aftermarket exhaust system is the best firstmodification for the money. This modification greatly decreasesturbo-lag, causing the car to perform better in all circumstances.

Best New Turbo for the 4EAT

Wehave found that a GT30R is the best turbo replacement for the 4EAT.Both the VF 34 and 39 have decent spool-up, with good mid-range and topend. If you plan on doing short block upgrades and running higher than18 psi, then we have found the GT30R to the our favorite.

Ofcourse, you will also need the necessary supporting mods to run a newturbo. A great deal of research must be done if you decide that a newturbo upgrade is right for you.

Using a Blow-Off Valve on a4EAT

Yes,it can be done, but the difference between using a BOV on a 4EAT isthat you will not hear much of the “pssshhh” sound when thetransmission shifts. This is because the 4EAT holds its boost duringshifts.

I heard that thetransmission in the Auto can hold more power than the transmission thatis used in the manual. Is this true?

Yes,this is true up to a point. The general consensus is that the 4EAT is astronger transmission than the 5MT and will last a very long time aslong as it is properly maintained and the abuse is kept to the minimum.The 4EAT is an extremely hard transmission to “break,” but it is unableto cope with too much extra power because its shifts are still tunedfor stock levels. Once you begin to cross to cross the 250 WHP barrier,you need to consider “beefing up” your transmission with a performancetorque converter and valve body upgrade. This need increases if youplan on launching your vehicle or driving it hard on a consistentbasis. Very few people have actually broken the 'teeth' of the 4EAT,and with a full internal transmission upgrade, the 4EAT will handleover 800WHP.

Can I manually shift the transmission ala Manumatic?

Althoughavailable as a true manumatic in Japan, the American version of theautomatic WRX does not contain that feature. You may manually selectthe gears, although there is little purpose as A) manually shiftingfrom a stop will not net you better acceleration and B) it does putextra stress on your transmission. I manually shift the automatic froma stop frequently and through the gears without any issues.

However,the manual functionality of the 4EAT can be useful for proper powerdelivery when cornering, it can also be used to place the car in abetter gear when racing from a roll.

4EAT Idiosyncrasies

Theautomatic in the WRX is a lot different than any other automatic that Ihave driven. The 5MT guys can choose the gear that they want their carto be in, keeping the car in it’s optimal power band. We can do that aswell, it just takes knowing how to fully use the automatic to takeadvantage of the car’s power band. Lets review the different gearselections on the automatic gear shifter. (please note that thefollowing information is intended towards stock vehicles. The rules arecompletely different for modded or even lightly modded cars).

1:This is a special situation gear (explained further in the manual) Itshould be used rarely, if never. Some owners like to start out in 1 to‘manually shift” the gears. Please note that the transmission will notautomatically upshift while in 1, so when you shift into the next gear,make sure to do so at least 1000 RPMs early because of the shiftingdelay.

2:This is also a special situation gear (explained further in yourmanual). Starting off in 2 will start your car in 2nd gear, not first,making it perfect for dyno tuning, but doesn’t make much sense fordaily driving. Please note that the transmission will not automaticallyupshift, so make sure to shift at least 1000 RPM early because of theshifting delay.

3rdgear is sometimes referred to in other cars as “D.” By selecting 3, thecar will drive normally but will not upshift into 4. Selecting 3 isideal when you are driving in any situation where you will not bemaintaining a constant speed (while driving in the city, for example,or climbing a steep grade). By selecting 3, your car will also be muchmore willing to downshift into 2 when extra power is required, making 3the Power Gear of the WRX. Interestingly enough, there have been somereports of a .2 second better time at the track thanks to the moreaggressive torque split while in 3.

Dis sometimes referred to in other cars as “OD.” By selecting D, the carwill drive normally and shift into 4th gear as soon as it can. This isonly ideal while maintaining a constant speed (Highway, freewaydriving). While in D, the car does not like to downshift into 2nd gear,making it a poor gear selection for times when quick passing responseis necessary.

Why the 4EAT is betterthen the 5MT.

Allof us are forgetting the main advantage of the Auto-WRX: the AWD systemitself. When we talk of 'Rally Proven', the 'proof' is actually missingin the Manual-WRX. Here is the reason why:

TheVTD-AWD system of the Auto-WRX is the most advanced AWD system ofSubaru, with a true torsen (torque sensing) planetary gear centerdifferential, which works in association with electronically controlledcontinuously variable multi-plate clutch-packs. The torque split is at45/55, with a slight rear bias in power, in normal driving, unless moreis needed front or back. This system equals in sophistication andeffectiveness, the best AWD systems currently available in the marketincluding the Audi Quattro (not the 'Quattro' present in the Audi TT,which is inferior to the VTD-AWD). The VTD-AWD system is conceptuallyidentical to the AWD systems present in the World Rally ConqueringSubarus, the significant difference being that the WRC cars have driveradjustable torque splits and are much more of a heavy-duty kind. Thehardware otherwise is identical in design. The Rally Subarus also havea true auto-manual transmission, which is actually a clutch-lessmanual, but the underlying AWD system is better adaptable to theAuto-WRX, not the manual-WRX, due to which the manual-WRX soldiers onwith an AWD system that is essentially tractor-technology. 'Gets thejob done' but nothing to write home about.

The other Auto-Subarus do not have thetorque-sensing center differential and drive more like a FWD car innormal driving.

Themanual WRX on the other hand, has the same Viscous coupling AWD systempresent in all other manual Subarus, which is a reactive system, asopposed to the proactive nature of the VTD-AWD system of the Auto-WRX.The viscous fluid which is used to transfer torque front/back needsslippage before it can react and transfer torque. Also, sincedifferential lock is achieved due to the viscous fluid being twisted(unlike the torque sensing incredibly sturdy planetary geardifferential in the Auto-WRX), the torque-transfer is both slow and inefficient. The AWD system of the manual WRX cannot be compared with theAudi Quattro or any other sophisticated AWD system. It does not havethe breadth of operation (cannot transfer the amount of torquefront/back like the VTD-AWD), the reactiveness (reacts slowly due toits very Viscous coupling nature) or the rapid torque transfercharacteristics (due to the 'reactive' nature of the system) of theVTD-AWD equipped Auto-WRX. With the Viscous coupling AWD system presentin the manual-WRX, Subaru certainly would not be winning manyrallies....just a heads-up.

Everythingelse remaining the same, I would have preferred a manual in the WRX.But in this particular case, everything else is not the same. Far fromit! Let’s face it - we love these cars for their AWD systems and notfor their 'manual gear shift capability'.

4EAT_Phase_II_Automatic_Transmission

4EAT Transmissions

So on that criteria,

theManual-WRX has a huge and glaring deficit andthe 4EAT is the “BestKept Secret”.

4eat Transmission